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1. static void MouseDown USBH_Mouse sender USBH_MouseEventArgs args Debug Print Button down number args ChangedButton Accessing Joysticks is very similar Here is the example modified to work with joysticks using System using System Threading using Microsoft SPOT using GHIElectronics NETMF USBHost namespace Test public class Program static USBH_Joystick j public static void Main Subscribe to USBH event USBHostController DeviceConnectedEvent DeviceConnectedEvent Sleep forever Thread Sleep Timeout Infinite static void DeviceConnectedEvent USBH_Device device if device TYPE USBH_DeviceType Joystick Debug Print Joystick Connected j new USBH Joystick device j JoystickXYMove JoystickXYMove j JoystickButtonDown JoystickButtonDown Copyright 2010 GHI Electronics LLC Page 108 170 Beginners guide to C and NET Micro Framework USB Host static void JoystickButtonDown USBH Joystick sender USBH_JoystickEventArgs args Debug Print Button Pressed args ChangedButton static void JoystickXYMove USBH Joystick sender USBH JoystickEventArgs args Debug Print x y sender Cursor X sender Cursor Y 22 2 Serial Devices Serial UART communication is a very common interface There are many companies that create chips that convert USB to serial GHI supports chipsets from
2. Copyright 2010 GHI Electronics LLC Page 71 170 Beginners guide to C and NET Micro Framework C Level 3J We first need to declare a variable to use Then in the for loop we need to give it three 107 arguments initial rule action In the very first loop we asked it to set variable i to zero Then the loop will keep running as long as the variable i is less then 10 Finally the for loop will increment variable i in every loop Let us make a full program and test it using System Threading using Microsoft SPOT using System namespace MFConsoleApplicationi public class Program public static void Main int i for i 0 i lt 10 i Debug Print i i ToString If we run the program above we will see that it is printing i from O to 9 but not 10 But we wanted it to run from 1 to 10 and not 0 to 9 To start from 1 and not 0 we need to set i to 1 in the initial loop Also to run to 10 we need to tell the for loop to turn all the way to 10 and not less than 10 so we will change the less than lt with less than or equal lt using System Threading using Microsoft SPOT using System namespace MFConsoleApplicationi public class Program f public static void Main 1 int i for i 1 i lt 10 i t Debug Print i i ToString Copyright 2010 GHI Electronics LLC Page 72 170 Beginners guide to
3. The code above requires Microsoft SPOT TinyCore assembly to run Then we need to use the presentation namespace so we can get the SystemMetrics Copyright O 2010 GHI Electronics LLC Page 95 170 Beginners guide to CZ and NET Micro Framework Displays Run the code and you will see a green line on the emulator MFConsoleApplicationl Program d public static void Mai a Sample Emulator Insert Eject Bitmap LCD new B clears the memor LCD Clear draw on memory LCD DrawLine Color transfer the bit LCD Flush tO 1 H pi Try to use what we learned on for loop to create multiple lines using System Threading using Microsoft SPOT using System using Microsoft SPOT Presentation using Microsoft SPOT Presentation Media namespace MFConsoleApplication1 public class Program public static void Main Bitmap LCD new Bitmap SystemMetrics ScreenWidth SystemMetrics ScreenHeight clears the memory and not the display LCD Clear int i for i 10 i lt 200 i 4 draw on memory LCD DrawLine Colors Green 1 10 i i 200 transfer the bitmap memory to the actual display LCD Flush Copyright 2010 GHI Electronics LLC Page 96 170 Beginners guide to C and NET Micro Framework Displays To draw text we would need to have a font resource first Add a new resource to the project You can use one of the res
4. Note how we ended the string with r n The r is code to tel the terminal to return back to the beginning of the line and n is to add new line When data is received on UART it is automatically queued a side so you wouldn t lose any data Note that there is limit on how much data the system can buffer so if you are debugging or not reading the data then close the serial port otherwise the system will become very slow and debugging execution will be very unreliable and slow Ideally events will be used so we are automatically receiving data We will cover events later This example will wait till byte is received then it prints back some string telling you what you have typed in transmitted using System Threading using System IO Ports using System Text namespace MFConsoleApplicationi public class Program public static void Main SerialPort UART new SerialPort COM1 115200 int read count 0 byte rx byte new byte 1 UART Open while true read one byte Copyright 2010 GHI Electronics LLC Page 78 170 Beginners guide to C and NET Micro Framework Serial Interfaces read_count UART Read rx_byte 1 if read count gt do we have data create a string string counter string You typed rx byte 0 ToString r n convert the string to bytes byte buffer Encoding UTF8 GetBytes counter string
5. Add Thread Sleep 1000 The Sleep method takes time in milliseconds So for 1 second we will need 1000 milliseconds using System using Microsoft SPOT using System Threading namespace MFConsoleApplication1 public class Program public static void Main while true i Debug Print Amazing Thread Sleep 1000 Try to run the program and look at the output window If you ve tried it on the emulator and it wasn t exactly 1 second don t worry about it Try it on real hardware FEZ and it will be very Copyright O 2010 GHI Electronics LLC Page 32 170 Beginners guide to C and NET Micro Framework C Level ly close to 1 second Let s create a second thread our first was automatically created remember We will need to create a new thread object handler reference and name it something useful like MyThreadHandler And create a new local method and name it MyThread Then run the new thread We are not using the Main thread anymore so will put it in endless sleep Here is the code listing If you don t understand it then don t worry about it All is needed at this point is that you know how to Sleep a thread using System using Microsoft SPOT using System Threading namespace MFConsoleApplication1 public class Program public static void MyThread while true Debug Print Amazing sleep this thread for 1 seond Thread Sleep 10 public stati
6. Debug Print ID device ID Interface device INTERFACE INDEX Type device TYPE When we detect a device we can communicate with it directly This requires a lot of knowledge on USB devices Fortunately most devices fall under standard classes and GHI already provide drivers for them 22 1 HID Devices Human Interface Devices like mice keyboards and joysticks are directly supported Using HID is event based Events are methods you create and then you subscribe them to a certain event When that event fires your method will get executed automatically using System using System Threading using Microsoft SPOT using GHIElectronics NETMF USBHost namespace Test public class Program static USBH Mouse mouse public static void Main 1 Subscribe to USBH event USBHostController DeviceConnectedEvent DeviceConnectedEvent Sleep forever Thread Sleep Timeout Infinite static void DeviceConnectedEvent USBH_Device device if device TYPE USBH_DeviceType Mouse Copyright 2010 GHI Electronics LLC Page 107 170 Beginners guide to C and NET Micro Framework USB Host Debug Print Mouse Connected mouse new USBH Mouse device mouse MouseMove MouseMove mouse MouseDown MouseDown static void MouseMove USBH Mouse sender USBH MouseEventArgs args Debug Print x y sender Cursor X sender Cursor Y
7. SendCommand Command LEFT SendCommand Command STOP Copyright 2010 GHI Electronics LLC Page 52 170 Beginners guide to C and NET Micro Framework Assembly E irmware Matchingg 11 Assembly Firmware Matching NETMF devices usually include extended features Those extended features require an extra assembly library to be added to the C projects so a user can make use of the new features For example NETMF doesn t support Analog pins but FEZ and other hardware from GHI does support analog pins To use the analog pins you need to add an assembly library provided by GHI then you have new classes objects that can be used to access those new features Important Note The firmware will fail to run if the version of the assembly library that used in the project does not match the version of the firmware This is very common issue that users run into when updating the firmware where the application just stop working and debugging seem to fail Here is what happens Scenario 1 A developer had received a new device This device happens to have firmware version 1 0 on it Then the developer went to the website and downloaded the latest SDK The SDK had firmware version 1 1 in it When trying to upload a project VS2010 will fail to attach to the device with no indication why The developer will now think the new device is not functioning actually the device is just fine but in this example the firmware is version 1
8. Thread Sleep 100 27 2 Analog There are hundreds or thousands of analog chipsets available that run on SPI I2C one wire etc Some read OV to 5V and other read 10V to 10V Basically there are too many options for reading more analog inputs to your device Some chips have specific tasks If we need to measure temperature we can connect a temperature sensor to an analog pin and then read the analog value and convert that to temperature That is an option but a better option will be to use a digital temperature sensor that run on I2C one wire or SPI This will give us a more accurate temperature reading and will also save an analog input for other uses Analog Buttons One trick to connect many buttons using a single pin is by using an analog pin The buttons will be connected to resistors This allows each button to set out a different voltage if pressed That voltage can then be measured to determine which button has been pressed Copyright O 2010 GHI Electronics LLC Page 136 170 Beginners guide to C and NET Micro Framework USB Clieng 28 USB Client want to start this section by pointing out that this is a little advanced topic If you just started out with NETMF then you may want to save it for later 28 1 Serial COM Debugging By default all GHI s NETMF devices use USB for deploying and debugging Optionally a developer may want to use the USB client not the host for something other than debuggi
9. Application Deployment Build Transport Build Events E Debug Device Resources USBizi USBizi v Services E Generate native stubs for internal methods Settings Root name for native stub files Reference Paths NET Micro Framework Create stub files in this directory Pressing F5 will now send our simple application to FEZ and it will run right inside the real hardware Switching from emulator to real hardware is that simple Try the steps we did with the emulator like setting breakpoints and using F11 to step in the code Note that Debug Print will still forward the debug messages from the hardware to the output window on Visual C Express Copyright O 2010 GHI Electronics LLC Page 20 170 Beginners guide to C and NET Micro Framework Component Drivers 7T Component Drivers FEZ components LEDs buttons temp sensor relays servo driver etc and FEZ shields Ethernet LCD motor driver etc come with example drivers Those drivers assume you know nothing about hardware For example to blink a LED you simply command the driver to do so It doesn t talk about processor pins and how to change the pin state etc On the other hand this book teaches the basics Use the component drivers to get started and then use this book to understand what the driver is actually doing Copyright O 2010 GHI Electronics LLC Page 21 170 Beginners guide to C and NET Micro Framework C Level 1g 8 C Level 1 This
10. There are many uses for input ports but the most common is to connect it to a button or a switch FEZ already includes an on board button connected to the loader pin The loader pin is used on power up to enter the boot loader but we can still use this pin at run time The button is enumerated as LDR or Loader The button will connect between ground and the input pin We will also enable the pull up resistor This means that the pin will be high pull up when button is not pressed and low connected to ground when the button is pressed We will read the status of the button and pass its state to the LED Note that the pin is high when the button is not pressed pulled high and it is low when the button is pressed This means the LED will turn off when the button is pressed The code using System using Microsoft SPOT using System Threading using Microsoft SPOT Hardware using GHIElectronics NETMF FEZ namespace MFConsoleApplication1 i public class Program public static void Main i OutputPort LED InputPort Button LED new OutputPort Cpu Pin FEZ Pin Digital LED true Copyright 2010 GHI Electronics LLC Page 38 170 Beginners guide to C and NET Micro Framework Digital Input amp Outputy Button new InputPort Cpu Pin FEZ Pin Digital LDR false Port ResistorMode PullUp while true LED Write Button Read Thread Sleep 10 Creating the InputPort ob
11. using Microsoft SPOT using System Threading using Microsoft SPOT Hardware using GHIElectronics NETMF Hardware using GHIElectronics NETMF FEZ namespace MFConsoleApplication1 public class Program public static void Main 1 AnalogOut VoltLevel new AnalogOut AnalogOut Pin FEZ Pin AnalogOut An3 VoltLevel SetLinearScale 0 3300 VoltLevel Set 1000 AnalogIn PinVoltage new AnalogIn AnalogIn Pin FEZ Pin AnalogIn AnO0 PinVoltage SetLinearScale 3300 while true int voltage PinVoltage Read Debug Print Voltage voltage 100 ToString voltage 1000 ToString Thread Sleep 200 Copyright O 2010 GHI Electronics LLC Page 62 170 Beginners guide to C and NET Micro Framework Analog input amp output Connect a wire between AnO and AOUT An3 and then run this program Note if no wire is connected then the analog pin is floating and can be of any value Try touching AINO and see how the numbers change then connect to AOUT to see if you get back 1V If you have a volt meter connect it to AOUT to verify we have 1V Note that it is not going to be exactly 1V but very close Copyright O 2010 GHI Electronics LLC Page 63 170 Beginners guide to C and NET Micro Framework Garbage Collectog 15 Garbage Collector When programming in older languages like C or C programmers had to keep track of objects and release them when necessary If an objec
12. copy 5 elements only One important and useful property of an array is the Length property We can use it to determine the length of an array byte MyArray1 new byte 10 1 2 3 4 5 6 7 8 9 10 byte MyArray2 new byte 10 Array Copy MyArray1 MyArray2 MyArray1 Length copy the whole array 16 4 String We have already used strings in many places We will review what we have learned and add more details Programs usually need to construct messages Those messages can be a human readable text Because this is useful and commonly used feature in programs C supports strings natively C knows if the text in a program is a string if it is enclosed by double quotes This is a string example string MyString Some string string ExampleString string ExampleString Whatever inside the double quotes is colored in red and considered to be a string Note how in the second line purposely used the same text in the string to match what used to assign the string C doesn t compile anything in quote red text but only take it as it is as a string You may still have confusion on what is the difference between a integer variable that have 5 in it and a string that have 5 in it Here is an example code Copyright 2010 GHI Electronics LLC Page 70 170 Beginners guide to C and NET Micro Framework C Level 35 string MyString int MyInteger EM ES 545 What
13. 1 Debug Print Resources GetString Resources StringResources SomeFile In this example will add a midi file Later in the book we will learn how to add a decoder and play this file First find your favorite midi file did a quick web search and downloaded lambada mid file Copyright O 2010 GHI Electronics LLC Page 92 170 Beginners guide to C and NET Micro Framework Loading Resources Start Page Resources resx Program cs T M Files Add Resource Remove Resource E WW SomeFile The file is about 33Kb Which is small in the computer world but for embedded systems it is not small The example below will work on devices with a lot of RAM like ChipworkX and Embedded Master On USBizi and FEZ it may or may not work We can still access large files with USBizi and FEZ but instead or reading the whole file at once we only read some if it send it to decoder then we come back and read more Details and instructions come later using System Threading using Microsoft SPOT using System namespace MFConsoleApplication1 public class Program public static void Main byte file_data Resources GetBytes Resources BinaryResources labamba Debug Print File Size is file _data Length ToString Copyright 2010 GHI Electronics LLC Page 93 170 Beginners guide to C and NET Micro Framework Displays m 20 Displays 20 1 Character Displays
14. 21 Real Tim NOON uasa acia 103 ANM NINE 104 22 T S EIOS iscsetctvetradsvie tetetanted Ese Gets veo Fe cvs 106 System Execution Recovery 152 22 1 HID DEVICES cda cec 107 Limiting Time Critical Tasks 123 22 2 Serial DEVICES iacit tiec m nis 109 22 3 V aS B STOTI EG icu ii eit dare Out dina 111 FAS ulis IL ETE abeodcnauteenioseasues 113 CEN BSIRESCD M 113 312 B Meton tiraniei ia 156 23 2 USB Mass Storage siuii 116 FII NOMIC eiiiai 158 24 3 Standard NET Sockets 121 244 Wi Fi 802 11 cie eee 122 33 1 Memory LItilizatiori aine 163 24 5 GPRS and 3G Mobile Networks 123 23 2 Object AMG CARO asocio oiii ees 163 25 Crypto piap MY Lace kick teat da Lata ctii seed 124 34 Missing TODICR iia eet iactacia 168 ESL ATE d a bob 124 ETHNIC 168 XTEA OB PS it cob creda 125 SRL DPW Rida acude oio i ad 168 232 socia eR ne icc um d n EE 125 34 3 Extended Weak Reference 168 26 X ME risame 128 34 3 SOTA PAO oo sai iier isaadateuce gane 168 25 1 5 MT i THEO iai acd otc 128 34 5 Runtime Loadable Procedures 168 26 2 Creatina XML ses cias coord 129 34 0 D taDasEg iussi iis c eias eiie 169 24 7 l uth Serei auae toc te 169 She VMS o oc daten coat e o is ER E 169 34 9 USB Host Raw eeeeeeeeeeees 169 Button MAIX aeo ce oii eee Rete 134 33 nal WOFRUSL aiii ca ooi sii oai dades 170 35 I Further Readlitig o
15. 24 TQ T1 16 minus 1 for sync 15 7 T2 2 8 15 14 8 24 TQs which is what we need TILLITI LANAA TATA const int BRP 12 const int T1 15 const int T2 8 For 500Kbps you can use BRP 6 and for 1Mbps you can use BRP 3 and for 125Kbps use BRP 24 and so on Keep T1 and T2 the same to keep the sampling pint Copyright 2010 GHI Electronics LLC Page 85 170 Beginners guide to C and NET Micro Framework Serial Interfaces the same between 70 and 80 Initialize CAN channel set bit rate CAN canChannel new CAN CAN CANChannel Channel 1 T2 1 lt lt 20 T1 1 lt lt 16 BRP 1 lt lt make new CAN message CAN CANMessage message new CAN CANMessage make a message of 8 bytes for int i i lt 8 i message data i byte i message DLC 8 8 bytes message ArbID OxAB ID message isEID false not extended ID message isRTR false not remote send the message canChannel PostMessage message wait for a message and get it while canChannel GetRxQueueCount 0 get the message using the same message object canChannel GetMessage message Now message contains the data ID flags of the received message Copyright O 2010 GHI Electronics LLC Page 86 170 Beginners guide to C and NET Micro Framework Output Compare 18 Output Compare This exclusive GHI feature allows developers to generate al
16. 5 1 ChipworkX Module If processing power and customization is needed then this is the ES right choice ChipworkX runs a 200Mhz ARM processor with 64MB 32 bit SDRAM and 8MB for user applications It also contains TIE 256MB internal flash for file system storage It includes all NETMF J major features and adds GHI exclusive features like WiFi and USB 5 host support n INIS261I V1 4 LJ ChipworkX also adds SQLite database support and allows users to load their own native code C assembly on the device using RLP Runtime Loadable Procedures RLP allows for advance 3 processor intensive and real time applications Copyright O 2010 GHI Electronics LLC Page 8 170 Beginners guide to C and NET Micro Framework Selecting a Deviceg 5 2 EMX Module This small module includes all NETMF major features and adds many GHI exclusive features On the software side File system TCP IP SSL Graphics debugging and more NETMF features are included GHI also adds WiFi PPP USB host USB device builder CAN Analog in out PWM and more As for the hardware It is 72Mhz ARM processor with 8MB SDRAM and 4 5MB FLASH jM The processor on EMX contains Ethernet MAC built right in with DMA transfers which gives it a large boost when compared with classical SPI based Ethernet chipset used by others 5 3 USBizi Chipset USBizi is the smallest and only single chip running NETMF in the world The software runn
17. Most character displays use the same interface Those displays are mostly 2 lines by 16 characters commonly known as 2x16 character displays The display can be controlled using 8 bit or 4 bit interface The 4 bit option is more favorable since it requires less IOs The interface uses RS Data Instruction RW Read Write E Enable and 4 bit data bus The display manual is the best resource of information but this is a simple example class to get the display running quick GHI offers an alternative to this display The SerialLCD display offered on www TinyCLR com will work on any single pin on FEZ The included driver makes using these displays even easier Using the display driver using GHIElectronics NETMF FEZ namespace MFConsoleApplication1 public class Program public static void Main FEZ Components SerialLCD LCD new FEZ_Components SerialLCD FEZ_Pin Digital Di5 LCD ClearScreen LCD CursorHome LCD Print FEZ Rocks 20 2 Graphical Displays Native support NETMF with its bitmap class can handle graphics very well The bitmap class supports Copyright O 2010 GHI Electronics LLC Page 94 170 Beginners guide to C and NET Micro Framework Displays images from BMP JPG and GIF file types The images can be obtained from the file system or the network but an easier option is to include the image in a resource The bitmap object can be used to draw images or shapes and to draw text using a
18. Those new Unicode characters can be more than 255 and so a byte is not sufficient and an integer four bytes is too much We need a type that uses 2 bytes of memory 2 bytes are good to store numbers from 0 to over 64 000 This 2 bytes type is called short which we are not using in this book Systems can represent characters using 1 byte or using 2 bytes Programmers decided to create a new type called char where char can be 1 byte or 2 bytes depending on the system Since NETMF is made for smaller systems its char is actually a byte This is not the case on Copyright O 2010 GHI Electronics LLC Page 68 170 Beginners guide to C and NET Micro Framework Cx Level 3J a PC where a char is a 2 byte variable Do not worry about all this mess do not use char if you do not have to and if you use it remember that it is 1 byte on NETMF 16 3 Array If we are reading an analog input 100 times and we want to pass the values to a method it is not practical to pass 100 variables in 100 arguments Instead we create an array of our variable type You can create an array of any object We will mainly be using byte arrays When you start interfacing to devices or accessing files you will always be using byte arrays Arrays are declared similar to objects byte MyArray The code above creates a reference of an object of type byte array This is only a reference but it doesn t have any object yet it is null If
19. case XmlNodeType Element Debug Print element break case XmlNodeType Text Debug Print text xmlr Value break case XmlNodeType XmlDeclaration Debug Print decl xmlr Name xmlr Value break case XmlNodeType Comment Debug Print comment break case XmlNodeType EndElement Debug Print end element break case XmlNodeType Whitespace Debug Print white space break case XmlNodeType None Debug Print none break default Debug Print xmlr NodeType ToString break xmlr Name xmlr Value Copyright 2010 GHI Electronics LLC Page 133 170 Beginners guide to C and NET Micro Framework Expanding VOS 27 Expanding l Os An application may require more digital pins or more analog pins than what is available on the processor There are ways to expand what is available 27 1 Digital The easiest way to expand digital pins is by using a shift register The shift register will then connect to the SPI bus Using SPI we can send or get the state of its pins Shift registers can be connected in series so in theory we can have unlimited digital pins Shift registers usually have eight digital pins If we connect three of them to a device over SPI we will have 24 new digital pin but we only use the SPI pins on the processor Another good example is the 1040 board that runs on I2C bus Also this board can be chained for a maximum of 320 lOs Button Matrix Device
20. http www nkcelectronics com rs232 to ttl converter board 33v232335 html In the PC world USB is more popular than serial ports Newer computers especially laptops do not have serial ports but every computer and laptop does have a USB interface For that reason many companies have created a USB to UART chipset USB lt gt RS232 cable is a very common device available at any computer store An interesting product from FTDI is a USB cable with UART interface note that it is TTL UART not RS232 on the other side of USB which means it can be connected directly to your processor s TTL UART The product number for this cable is TTL 232R 3V3 To summarize all above you can interface two processors by connecting UART pins directly To interface a processor to a PC you need to convert the UART signals to RS232 or USB using one of the ready circuits like MAX232 for RS232 and FT232 for USB NETMF supports serial ports UART in the same way the full NET framework on the PC is supported To use the Serial port add Microsoft SPOT Hardware SerialPort assembly and add using System IO Ports at the beginning of your code Note that serial ports on PC s and on NETMF are named COM ports and they start from COM1 There is no COMO on computer systems This can cause a little confusion when we want to map the COM port to the UART port on the processor because the processor usually start with UARTO not UART1 So COM1 is UARTO and COM2 is UART1 etc
21. i lt 1000 i WriteRegister 5 100 ticks DateTime Now Ticks ticks ms ticks TimeSpan TicksPerMillisecond Debug Print Time ms ToString When running the code on on FEZ USBizi we notice that the Garbage Collector had to run 10 times The garbage collector prints it activity on the output window Time taken for the code to run is 1911 ms which is about 2 seconds Now let us modify the code as showing below We now have the SPI object created globally and will always be there We are still allocating the buffer in every loop using System Threading using System using Microsoft SPOT Hardware using Microsoft SPOT namespace MFConsoleApplication1 public class Program static SPI _spi new SPI new SPI Configuration Cpu Pin GPIO_NONE false false true 1000 SPI SPI module SPI1 static void WriteRegister byte register num byte value byte buffer new byte 2 buffer 0 register num buffer 1 value _spi Write buffer _spi Dispose public static void Main long ms Copyright 2010 GHI Electronics LLC Page 165 170 Beginners guide to C and NET Micro Framework Thinking Smallg long ticks DateTime Now Ticks for int i 0 i 1000 i WriteRegister 5 100 ticks DateTime Now Ticks ticks ms ticks TimeSpan TicksPerMillisecond Debug Print Time ms ToString In the second examp
22. send the bytes on the serial port UART Write buffer 0 buffer Length wait Thread Sleep 10 This last example is a loop back Connect a wire from TX to RX on your board and it will send data and make sure it is receiving it correctly using System Threading using System IO Ports using System Text using Microsoft SPOT namespace MFConsoleApplication1 public class Program public static void Main 1 SerialPort UART new SerialPort COM1 115200 int read count 0 byte tx data byte rx data new byte 10 tx data Encoding UTF8 GetBytes FEZ UART Open while true flush all data UART Flush send some data UART Write tx data 0 tx data Length wait to make sure data is transmitted Thread Sleep 100 read the data read count UART Read rx data 0 rx data Length Copyright O 2010 GHI Electronics LLC Page 79 170 Beginners guide to C and NET Micro Framework Serial Interfacesg if read count 3 we sent 3 so we should have 3 back Debug Print Wrong size read count ToString else the count is correct so check the values I am doing this the easy way so the code is more clear if tx data 0 rx_data if tx data 1 rx data 1 if tx data 2 rx data 2 Debug Print Perfect data Thread Sleep 100 17 2 SPI SPI uses three or four wires for transferring data In UART
23. 0 and the assembly is version 1 1 so the system will refuse to run To fix the issue update the firmware on the device to match the firmware in the SDK Scenario 2 A developer has a perfectly working system that for example uses firmware version 2 1 Then a new SDK comes out with firmware version 2 2 so the developer installs the new SDK on the PC then uploads the new firmware to the device FEZ When rebooting the device it stops working because the new loaded firmware is version 2 2 but the user application still uses assembly version 2 1 To fix this issue open the project that has the user application and remove any device specific assemblies After they are removed go back and add them back With this move the new files will be fetched from the new SDK Boot up Messages We can easily see why the system is not running using MFDeploy NETMF outputs many useful messages on power up Should the system become unresponsive fails to run or for any other debug purposes we can use MFDeploy to display these boot up messages Also all Debug Print messages that we usually see on the output window are visible on MFDeploy To display the boot up messages click on Target gt Connect from the menu then reset the device Right after you reset the device in one second click on ping MFDeploy will freeze for a second then display a long list of messages Copyright O 2010 GHI Electronics LLC Page 53 170 Beginners guide to
24. 0 Messages Description Q1 Thetype or namespace name Microsoft F could not be found are you missing a using directive or an assembly reference Copyright 2010 GHI Electronics LLC Page 29 170 Beginners guide to C and NET Micro Framework C Level J Let s add it back and make sure our program still runs Right click on the work References and select Add Reference 5 MFConsoleApplication H al Properties j Add Reference eat Add Service Reference H Ga RESOUFCESTESX In the new window select NET tab and then select Microsoft SPOT Native and click OK NET Projects Recent Browse Component Name gt Version Runtime Microsoft SPOT Hardware 3 0 7186 0 v2 0 5072 Microsoft SPOT Hardware SerialPort 3 0 7186 0 v2 0 5072 Microsoft SPOT Hardware Usb 3 0 7186 0 v2 0 5072 gt Microsoft SPOT Ink 3 0 7186 0 v2 0 5072 Microsoft SPOT IO 3 0 7186 0 v2 0 5072 _ Microsoft SPOT Native 3 0 7186 0 v2 0 5072 Microsoft SPOT Net 3 0 7186 0 v2 0 5072 Microsoft SPOT Net Security 3 0 7186 0 v2 0 5072 Microsoft SPOT TinyCore 3 0 7186 0 v2 0 5072 Microsoft SPOT Touch 3 0 7186 0 v2 0 5072 mscorlib 3 0 7186 0 v2 0 5072 Try the program to make sure its still running If you have any errors please go back and read more to fix it before moving on What Assemblies to Add Throughout this book provide
25. C and NET Micro Framework Assembly E irmware Matchingg amp E NET Micro Framework Deployment Tool Application Deployment Manage Device Keys Configuration Device Capabilities Ctrl Shift C Disconnect Ctrl F5 Note that on FEZ Domino the reset button is available on the board For FEZ Mini you need to connect a switch to the reset pin or if you have FEZ Mini in the starter kit or robot kit then you can use the reset button on the board Pinging TinyCLR Connecting to USBizi USBizi Connected Loading start at 49a78 end 524d4 Attaching file Assembly mscorlib 4 0 1681 0 3572 RAM 29700 ROM 17609 METADATA AssemblyRef 0 bytes 0 elements 0 bytes 0 eTinyCLR 0 bytes 0 elements 0 bytes 0 elements 1032 bytes 129 elements 232 bytes 115 elements 1448 bytes 723 elements Attributes TypeSpec Resources Resources Files Resources Data 0 bytes 0 elements 16 bytes 4 elements 232 bytes 29 elements 16 bytes 2 elements 437 bytes 990 bytes annn nm Copyright O 2010 GHI Electronics LLC Page 54 170 Beginners guide to C and NET Micro Framework Pulse Width Modulationg 12 Pulse Width Modulation PWM is a way of controlling how much power is provided to a device Dimming a LED or slowing down a motor is best done using a PWM signal If we apply power to a LED it comes completely on and if we shut off the power then it is completely off Now what if we turn the LED on for 1ms
26. FTDI Silabs and Prolific Also there is a standard USB class defined for serial communication called CDC Communication Device Class This class is supported as well Note here that the USB chipsets are made to be somewhat customized So a company can use a FTDI chip to make their product run on USB and they will change the strings in USB descriptors so when you plug in their device to a PC you will see the company name not FTDI name They can also change the USB VID PID vendor ID and product ID A good example is a USB GPS device Almost all those USB GPS devices use prolific chip which is supported by GHI Many of the interface products on the market use FTDI chipset using System using System Text using System Threading using Microsoft SPOT using GHIElectronics NETMF USBHost namespace Test class Program static USBH_SerialUSB serialUSB static Thread serialUSBThread Prints data every second Copyright O 2010 GHI Electronics LLC Page 109 170 Beginners guide to C and NET Micro Framework USB Hosty public static void Main Subscribe to USBH event USBHostController DeviceConnectedEvent DeviceConnectedEvent Sleep forever Thread Sleep Timeout Infinite static void DeviceConnectedEvent USBH Device device Debug Print Device connected switch device TYPE case USBH_DeviceType Serial_FTDI FTDI connected serialUSB new USBH_SerialUSB device 9600 System IO
27. Microsoft SPOT IO using GHIElectronics NETMF IO using GHIElectronics NETMF USBHost namespace Test class Program public static void Main Subscribe to RemovableMedia events RemovableMedia Insert RemovableMedia_Insert RemovableMedia Eject RemovableMedia Eject Subscribe to USB events USBHostController DeviceConnectedEvent DeviceConnectedEvent Sleep forever Thread Sleep Timeout Infinite static void DeviceConnectedEvent USBH Device device if device TYPE USBH DeviceType MassStorage Debug Print USB Mass Storage detected Hr esws Ef eus Copyright 2010 GHI Electronics LLC Page 111 170 Beginners guide to C and NET Micro Framework USB Host The next section explains how to access the files on the USB memory Copyright O 2010 GHI Electronics LLC Page 112 170 Beginners guide to C and NET Micro Framework File System 23 File System File system is supported in NETMF 3 0 GHI adds more functionality to the standard support For example a SD card can be mounted to the file system or mounted to the USB device MSC service When mounted to the filer system developers can access the files But when mounted to the USB device MSC a PC connected to the USB port will see a USB card reader with SD card This is good for creating data logger for example The device will log data on the SD card and when the device is plugged to a PC the device will be
28. NET Micro Framework Serial Interfacesg the slave using SSEL Slave Select pin This pin can be called CS Chip Select as well In theory the master can have unlimited slaves but it can only select one of them at any given time The master will only need 3 wires SCK MISO MOSI to connect to all slaves on the bus but then it needs a separate SSEL pin for each one of the slaves Some SPI devices slaves can have more than one select pin like VS1053 MP3 decoder chip that uses one pin for data and one pin for commands but both share the 3 data transfer pins SCK MOSI MISO SPI needs more wires than other similar buses but it can transfer data very fast A 50Mhz clock is possible on SPI that is 50 million bits in one second NETMF devices are always SPI masters Before creating a SPI object we would need a SPI configuration object The configuration object is used to set the states of the SPI pins and some timing parameters In most cases you need the clock to be idle low false with clocking on rising edge true and with zero for select setup and hold time The only thing you would need to set is the clock frequency Some devices may accept high frequencies but others do not Setting the clock to 1000Khz 1Mhz should be okay for most getting started projects This example is sending receiving swapping if you will 10 bytes of data on SPI channel 1 Note that NETMF start numbering SPI channels module from 1 but on processors the ch
29. PCs have terminal programs that open the serial ports to send receive data Any data received will be displayed on the terminal software and any data typed in the terminal will be sent out on the serial port Teraterm is one of common and free software that we recommended Flowing is a program that sends a counter value every 10 times a second The data is sent at 115200 so make sure the terminal is setup the same way This program sends the data on COM1 of your NETMF device This COM number has nothing to do with COM number on your PC For example you may have a USB serial port on your PC that maps to COM8 and so you need to open COMSGB on your PC not COM1 but the NETMF program will still use COM1 because it uses UARTO COM1 using System Threading using System IO Ports using System Text namespace MFConsoleApplication1 public class Program public static void Main SerialPort UART new SerialPort COM1 115200 int counter 0 UART Open Copyright 2010 GHI Electronics LLC Page 77 170 Beginners guide to C and NET Micro Framework Serial Interfacesg while true create a string string counter string Count NANAS convert the string to bytes byte buffer Encoding UTF8 GetBytes counter_string send the bytes on the serial port UART Write buffer 0 buffer Length increment the counter counter wait Thread Sleep 10 counter ToString
30. Ports Parity None 8 System IO Ports StopBits One serialUSB Open serialUSBThread new Thread SerialUSBThread serialUSBThread Start break case USBH DeviceType Unknown SiLabs but not recognized force SiLabs USBH Device silabs new USBH Device device ID device INTERFACE INDEX USBH DeviceType Serial SiLabs device VENDOR ID device PRODUCT ID device PORT NUMBER serialUSB new USBH SerialUSB silabs 9600 System IO Ports Parity None 8 System IO Ports StopBits One serialUSB Open serialUSBThread new Thread SerialUSBThread serialUSBThread Start break static void SerialUSBThread Print Hello World every second byte data Encoding UTF8 GetBytes Hello World r n while true Thread Sleep 1000 serialUSB Write data 0 data Length Copyright 2010 GHI Electronics LLC Page 110 170 Beginners guide to C and NET Micro Framework USB Host 22 3 Mass Storage Storage devices like USB hard drives and USB thumb memory drives use the same USB class MSC Mass Storage Class GHI library directly support those devices USB only defines how to read write raw sectors on the media The operating system then handles the file system NETMF supports FAT32 and FAT16 file system To access the files on a USB media we first need to detect it then we need to mount the media using System using System IO using System Threading using Microsoft SPOT using
31. SUE Senteer gd Solution MFConsoleApplication 1 project ToN 5 9l MFConsoleApplication H Sa Properties B L References C3 Microsoft SPOT Hardware 43 Microsoft SPOT Native 42 mscorlib using System Threading bere Microsoft SPOT using Microsoft SPOT Hardware namespace MFConsoleApplicationi 1 public class Progran E We are now ready to use the digital pins 9 1 Digital Outputs We know that a digital output pin can be set to zero or one Note that one doesn t mean itis 1 volt but it means that the pin is supplying voltage If the processor is powered off of 3 3V then the state 1 on a pin means that there is 3 3V on the output pin It is not going to be exactly 3 3V but very close When the pin is set to zero then it is voltage is very close to zero volts Program cs H Gaal Resources resx Those digital pins are very weak They can t be used to drive devices that require a lot of power For example a motor may run on 3 3V but you can NOT connect it directly to the processor s digital pin That is because the processor output is 3 3V but with very little power The best you can do is drive a small LED or signal 1 or O to another input pin Copyright 2010 GHI Electronics LLC Page 34 170 Beginners guide to C and NET Micro Framework Digital Input amp Outputy All FEZ boards have a LED connected to a digital pin We want to blink this led Digital output pins are con
32. and then off for 1ms In reality it is blinking on and off very fast but our eyes would never see it blinking that fast causing our eyes to see the LED to be dimmer than before We calculate this using on offt on x100 50 So the LED is only getting half the energy So if we turn the LED on for 1ms and off for 9ms we will end up with 1 1 9 x100 10 energy so the LED is very dimmed PWM is very simple to generate but if we are going to toggle a pin few hundred or thousand times a second then we are wasting a lot of processor power There are devices that generate PWM signals more efficiently Also many processors include a built in circuitry needed to generate PWM in hardware This means we can setup the PWM hardware to generate a PWM signal and then it is done automatically without the need for processor interaction FEZ included few pins that can serve as PWM pins The FEZ library includes everything needed to activate PWM on any one of those pins Here is an example that creates a PWM object that sets the PWM to 10 Khz 10 000 clocks sec and the duty cycle to 50 5096 energy PWM pwm new PWM PWM Pin FEZ Pin PWM LED pwm Set 10000 50 FEZ includes an enumeration of what pins have PWM hardware Using the PWM enumeration we can easily find the PWM pins on your device Visual studio will give you a list of them while you are typing your code just like this image t PWM pwm new PWM byte FEZ Pin PWM pwm Se
33. connected or disconnected any time There are events generated when devices are connected or disconnected The developer should subscribe to these events and handle devices accordingly Since this is a beginner book will assume that the device will always be connected to the system With USB HUB support devices can be connected directly to the USB host port or a user may connect multiple USB devices through a USB hub First let us detect what devices are connected The first thing to do is start the system manager then we can get a list of available devices Remember that we need to add the GHI library assembly to our resources using System using System Threading using Microsoft SPOT using GHIElectronics NETMF USBHost namespace Test class Program public static void Main Subscribe to USBH events USBHostController DeviceConnectedEvent DeviceConnectedEvent USBHostController DeviceDisconnectedEvent DeviceDisconnectedEvent Sleep forever Thread Sleep Timeout Infinite static void DeviceConnectedEvent USBH_Device device Copyright 2010 GHI Electronics LLC Page 106 170 Beginners guide to C and NET Micro Framework USB Host Debug Print Device connected Debug Print ID device ID Interface device INTERFACE INDEX Type device TYPE static void DeviceDisconnectedEvent USBH Device device Debug Print Device disconnected
34. do you think the actual value of the variables now For integer it is 10 as 5 5 10 But for string this is not true Strings do not know anything about what is in it text or numbers make no difference When adding two strings together a new string is constructed to combine both And so 5 5 55 and not 10 like integers Almost all objects have a ToString method that converts the object information to a printable text This demonstration shows how ToString works int MyInteger 5 5 string MyString The value of MyInteger is MyInteger ToString Debug Print MyString Running the above code will print The value of Mylnteger is 10 Strings can be converted to byte arrays if desired This is important if we want to use a method that only accepts bytes and we want to pass our string to it If we do that every character in the string will be converted to its equivalent byte value and stored in the array using System Text byte buffer Encoding UTF8 GetBytes Example String 16 5 For Loop Using the while loop is enough to serve all our loop needs but for loop can be easier to use in some cases The simplest example is to write a program that counts from 1 to 10 Similarly we can blink an LED 10 times as well The for loop takes three arguments on a variable It needs the initial value how to end the loop and what to do in every loop int i for i 0 i lt 10 i do something
35. interrupt on high and low edges Copyright 2010 GHI Electronics LLC Page 39 170 Beginners guide to C and NET Micro Framework Digital Input amp Outputy InterruptPort IntButton new InterruptPort Cpu Pin FEZ Pin Interrupt LDR true Port ResistorMode PullUp Port InterruptMode InterruptEdgeBoth add an interrupt handler to the pin IntButton OnInterrupt new NativeEventHandler IntButton OnInterrupt do anything you like here Thread Sleep Timeout Infinite static void IntButton_OnInterrupt uint port uint state DateTime time set LED to the switch state LED Write state Note Not all pins on the processor support interrupts but most of them do For easier identification of the interrupt pins use the enumeration for Interrupt instead of Digital as shown in earlier code 9 4 Tristate Port If we want a pin to be an input and output what can do A pin can never be in and out simultaneously but we can make it output to set something and then make it input to read a response back One way is to Dispose the pin We make an output port use it and then dispose it Then we can make the pin input and read it NETMF supports better options for this through Tristate port Tristate means three states that is input output low and output high One minor issue about tristate pins is that if a pin is set to output and then you set it to output again then we will
36. is properly connected The NETMF SDK comes with software from Microsoft called MFDeploy There are many good uses for MFDeploy but for now we only need it to ping the device Basically ping meas MFDeploy will say Hi to the device and then checks if the device will respond with Hi This is good to make sure the device connected properly and transport with it has no issues Open MFDeploy and connect FEZ using the included USB cable to your PC If this is the first time you plug in FEZ Windows will ask for drivers Supply the driver from the SDK folder and wait till windows is finished In the drop down menu select USB You should see USBizi showing in the device list You will see USBizi because FEZ is based on USBizi chipset Select USBizi and click the Ping button You should now see back TinyCLR 8E NET Micro Framework Deployment Tool _ Target Options Help Device Usb WSEEMISER Ping Bese Image File v Browse Deploy Copyright O 2010 GHI Electronics LLC Page 19 170 Beginners guide to C and NET Micro Framework Getting Started Deploying to Hardware Now that we checked that the hardware is connected using MFDeploy we need to go back to Visual C express From the project properties select USB for transport and USBizi for the device Make sure your setup looks similar to the image below Start P Resources resx Program cs MFConsoleApplication
37. it is doing is running every program for a short time then it stops it and goes on to run the next program Generally threading is not recommended for beginners but there are things that can be done much easier using threads For example you want to blink an LED It would be nice to blink an LED in a separate thread and never have to worry about it in the main program Also adding delays in the code require the threading namespace You will understand this better in coming examples Copyright O 2010 GHI Electronics LLC Page 31 170 Beginners guide to C and NET Micro Framework C Level ly By the way LED stands for Light Emitting Diodes You see LEDs everywhere around you Take a look at any TV DVD or electronic device and you will see a little Red or other color light bulb These are LEDs FEZ comes with with a LED library to simplify this even further This book explains how to directly control pins devices Add using System Threading to your program using System used Microsoft SPOT using System Threading That is all we need to use threads It is important to know that our program itself is a thread On system execution start up C will look for Main and run it in a thread We want to add a delay in our thread our program so it will print the word Amazing once every second To delay a thread we put it to Sleep Note that this Sleep is not for the whole system It will only Sleep the thread
38. many examples but do not tell you what assemblies am using This is really easy to figure out from the documentation but you may find it difficult sometimes Why not just add them all As a beginner your applications are still very small so Copyright O 2010 GHI Electronics LLC Page 30 170 Beginners guide to C and NET Micro Framework C Level ly you will have a lot of memory even if you add all of the assemblies even if you are not using them The assemblies below are most commonly used Add them for all of your projects for now Once you know where everything belongs you can start removing the ones you don t need GHlElectronics NETMF Hardware GHlElectronics NETMF IO GHIElectronics NETMF System Microsoft SPOT Hardware Microsoft SPOT Native Microsoft SPOT Hardware SeriaPort Microsoft SPOT IO mscorlib System System lO Don t forget about using one of the following according to what device you are using These contain the pin definitions FEZMini GHlIElectronics NETMF FEZ FEZDomino GHlIElectronics NETMF FEZ Threading This can be a very advanced topic Note that only very basic information is covered here Processors programs only run one instruction at once Remember how we stepped in the code Only one instruction got executed and then the flow went on to the next instruction Then how is it possible that your PC can run multiple programs at the same time Actually your PC is never running them a once What
39. receive an exception One way to come around this is by checking the direction of the pin before changing it The direction of the pin is in its property Active where false means input and true is output personally do not recommend the use of Tristate ports unless absolutely necessary using System using Microsoft SPOT using System Threading using Microsoft SPOT Hardware using GHIElectronics NETMF FEZ namespace MFConsoleApplication1 Copyright 2010 GHI Electronics LLC Page 40 170 Beginners guide to C and NET Micro Framework Digital Input amp Outputy public class Program static void MakePinOutput TristatePort port if port Active false port Active true static void MakePinInput TristatePort port if port Active true port Active false public static void Main TristatePort TriPin new TristatePort Cpu Pin FEZ_Pin Interrupt LDR false false Port ResistorMode PullUp MakePinOutput TriPin make pin output TriPin Write true MakePinInput TriPin make pin input Debug Print TriPin Read ToString Note Due to internal design TristatePort will only work with interrupt capable digital pins Important Note Be careful not to have the pin connected to a switch then set the pin to output and high This will damage the processor would say for beginner applications you do not need a tristate port so do not use it till you are comfort
40. return var3 because it is integer variable and so we had to convert it to a string To do that we create a new variable object named MyString Then convert var3 ToString and place the new string in MyString The question now is how come we called a ToString method on a variable of type interger In reality everything in C is an object even the built in variable types This book is not going into these details as it is only meant to get you started This is all done in multiple steps to show you how it is done but we can compact everything and results will be exactly the same string Add int vari int var2 return vari var2 ToString recommend you do not write code that is extremely compact like the example above till you are very familiar with the programming language Even then there should be limits on how much you compact the code You still want to be able to maintain the code after sometime and someone else may need to read and understand your code Copyright O 2010 GHI Electronics LLC Page 48 170 Beginners guide to C and NET Micro Framework C Level 2 10 5 Classes All objects we talked about so far as actually classes in C In modern object oriented programming languages everything is an object and methods always belong to one object This allows for having methods of the same name but they can be for completely different objects A human can walk and a cat can also
41. servos The PWM class provides two methods Set and SetPulse methods Earlier we utilized PWM Set which very well suited for setting energy levels For controlling servos using SetPulse is more suitable So how do servos work This is best explained in this image found on www pc control co uk 1 50 ms Neutral A 1 0 1 25 ms 0 degrees 1 75 ms 180 degrees H su 00 O Susz Tl Suns T Susz T su OO O Sus2 T Suns T Susz T su 00 O Susz T Suns T Susz T Copyright O 2010 GHI Electronics LLC Page 57 170 Beginners guide to C and NET Micro Framework Pulse Width Modulationg You can control the position of a servo by providing it with a pulse see image above If the pulse width is about 1 25ms then the servo is at 0 degrees Increasing the pulse to 1 25ms will move the servo to 90 degrees neutral A wider pulse of 1 75ms will move the servo to 180 degrees Okay those is easy to generate using PWM but are still missing one piece of info The image tells us how wide in time is the high pulse but what about the low time Servos expect a pulse every 20ms to 30ms but this is not very critical to servos So we now have everything we need Before proceed want to explain what the period is A period of a frequency signal is the high time plus the low time Now we are ready for some code The method PWM SetPulse needs the high time and the period of the signal Since our servo low time is not crit
42. sockets A socket is a virtual connection between 2 devices on a network GHI extended the TCP IP support to cover PPP and WiFi Through PPP two devices can connect through serial connection Serial connection can be a phone line modem or a 3G GPRS modem With PPP NETMF devices can connect to the internet using 3G cell phone networks It is also possible to connect two NETMF devices through wired or wireless XBee Bluetooth others serial connection Also with WiFi support NETMF devices can connect to standard secure or unsecured wireless networks NETMF also support SSL for secure connection The support for networks is standard and complete HTTP SSL Sockets etc on EMX Embedded Master and for ChipworkX 24 1 USBizi FEZ Network Support When it comes to ram hungry networking USBizi will require some external support For example USBizi wired networking is done through Wiznet W5100 Hardwired TCP IP chip When USBizi want to make a network connection all it has to do is send a request to Wiznet 5100 of the connection an then the chip will do the rest Same as for data transfer where USBizi will hand the data to W5100 and then this chip will take care of the rest The Wiznet W5100 works over SPI bus Current driver is provided by GHI to handle W5100 right from C This is a beta driver and it is for testing purposes only There is development that is being done to provide W5100 driver right into the USBizi firmware This is
43. works just like a serial port but in reality it is actually a USB port One important thing want to mention here is that usually CDC drivers handle one transaction in every frame The max EP size on USB is 64 bytes and there 1000 frames seconds on full speed USB This means the maximum transfer rate for CDC drivers is 64KB sec think Microsoft realized the needs for CDC and higher transfer rate and did enhance this limitation Last time tested the transfer speed on my win7 machine was able to see about 500KB sec The following will create a USB CDC and send Hello world to PC every second using System using System Threading using Microsoft SPOT using Microsoft SPOT Hardware using GHIElectronics NETMF USBClient using GHIElectronics NETMF Hardware public class Program public static void Main Check debug interface if Configuration DebugInterface GetCurrent Configuration DebugInterface Port USB1 throw new InvalidOperationException Current debug interface is USB It must be changed to something else before proceeding Refer to your platform user manual to change the debug interface Start CDC USBC CDC cdc USBClientController StandardDevices StartCDC Send Hello world to PC every second Append a new line too byte bytes System Text Encoding UTF8 GetBytes Hello world r n while true Check if connected to PC if USBClientController GetState USBClient
44. wouldn t fit in your pocket Another problem is how would you measure temperature and acceleration on a PC If you make this project using classic microcontrollers like AVR or PIC micro all this can be done but then you need a compiler for the micro you choose probably not free a week to learn the processor a week to write serial driver a month or more to figure out the FAT file system and more time for memory cards etc Basically it can be done in few weeks of work Another option is utilizing simpler methods BASIC STAMP PICAXE Arduino etc All these products simplify a design but each one has its limitation Only a couple of them have debugging capabilities Finally these devices are not normally suited for mass production 3 1 Advantages If you are using NET Micro Framework then there are many advantages It runs on Microsoft s Visual C Express free and and high end IDE NET Micro Framework is open source and free Your code will run on all these devices with almost on changes Full debugging capabilities Breakpoints stepping in code variables etc Has been tested in many commercial products so quality is assured Includes many bus drivers SPI UART I2C etc No need to use processors datasheets because of the standard framework d Pel E ee ie a If you are already a PC C programmer then you are already an embedded system developer with NETMF Throughout this document may refer to NET Micro Fram
45. 0 100 setup the interrupt pin InterruptPort LDR new InterruptPort Cpu Pin false Port ResistorMode PullUp Port InterruptMode InterruptEdgeLow while true Thread Sleep 3000 blink LED for 3 seconds sleep Power Hibernate Power WakeUpInterrupt InterruptInputs we get here when we wakeup Why did the example above not work When you create an interrupt or input pin interrupts are enabled only if glitch filter is used or if an event handler is installed So to make the work above work you only need to enable the glitch filter Here is the code that works using System using System Threading using Microsoft SPOT using Microsoft SPOT Hardware using GHIElectronics NETMF Hardware using GHIElectronics NETMF Hardware LowLevel using GHIElectronics NETMF FEZ public class Program public static void Main blink LED FEZ Components LED led new FEZ Components LED FEZ Pin Digital LED led StartBlinking 100 100 setup the interrupt pin with glitch filter enableled InterruptPort LDR new InterruptPort Cpu Pin 0 true Port ResistorMode PullUp Port InterruptMode InterruptEdgeLow while true Thread Sleep 3000 blink LED for 3 seconds sleep Power Hibernate Power WakeUpInterrupt InterruptInputs we get here when we wakeup Copyright 2010 GHI Electronics LLC Page 148 170 Beginners guide to C and NET Micro Framework Low Powery Another
46. 200 or others Through UART two processors can connect directly by connecting TXD on one side to RXD on the other side and vice versa Since this is just a digital IO on the processor the voltage levels on UART TXD RXD pins will be OV low and 3 3V or 5V high In industrial systems or when long wires are used 3 3V or even 5V doesn t provide enough room for error There are standards that define how we can take UART standard signal and convert it to higher voltages or differential signal to allow data transfer with better reliability The most common one is RS232 Almost all computers are equipped with RS232 port With RS232 data is simply UART but the voltage levels are converted from TTL OV to 3 3V to RS232 levels 12V to 12V One important fact about RS232 is that the voltage level is inverted from how we would logically think of it When the signal is logically low the voltage is at 12V and when the signal is logically high the voltage is at 12V There are many ready chips that convert TTL levels to RS232 levels like MAX232 and MAX3232 When we need to interface a processor using UART to a computer s serial port we need to convert the UART TTL level to RS232 using some circuitry For beginners or a quick hack there are companies who provide ready circuits that convert RS232 to UART This is just an example Copyright O 2010 GHI Electronics LLC Page 76 170 Beginners guide to C and NET Micro Framework Serial Interfaces
47. 7 0x93 Oxf2 Oxfd Ox7b Oxfa 0xa5 0x72 0x57 0x45 Oxc8 0x45 Oxe7 0x96 0x55 Oxf9 0x56 Ox4f Ox1a 0xea Ox8f 0x55 the public key always starts with 0x01 0x00 0Ox01 and the reast are all zeros byte public key new byte 128 public key 0 public key 2 1 Key RSA rsa encrypt Key RSA rsa decrypt new Key RSA module public key new Key RSA module private key The data we want to encrypt string original string FEZ is so easy Copyright O 2010 GHI Electronics LLC Page 126 170 Beginners guide to C and NET Micro Framework Cryptographyg convert to byte array byte original_data UTF8Encoding UTF8 GetBytes original_string Encrypt the data byte encrypted_bytes rsa encrypt Encrypt original data 0 original data Length null Decrypt the data byte decrypted bytes rsa decrypt Decrypt encrypted bytes 0 encrypted bytes Length null print the decrypted data string decrypted_string new string Encoding UTF8 GetChars decrypted bytes Debug Print Data Size original string Length Data original string Debug Print Encrypted Data size encrypted bytes Length Decrypted Data decrypted string RSA encrypted data size is not the same as the raw data size Keep this in mind when planning on transferring or saving RSA encrypted data RSA is far more processor intensive than XTEA which can be a problem for small syste
48. AN peripheral Copyright O 2010 GHI Electronics LLC Page 84 170 Beginners guide to C and NET Micro Framework Serial Interfaces this is NOT the baud rate This is called the BRP 2 Figure out how many clocks you need to make up one bit Usually this is 24 or 16 This is called TQ 3 Assign values to T1 and T2 where T1 T2 1 TQ Let us assume we need 250Kbps 1 From 72Mhz system clock want the CAN clock to be 6Mhz so need to divide by 12 BRP 12 2 6Mhz 250kbps 24 TQ we usually want 16 or 24 3 T1 15 T2 8 will give us 15 8 1 24 and this is what we need got the T1 and T2 values from http Awww kvaser com can protocol index htm picked the first value and subtracted 1 from T1 because the calculator included the sync bit GHI Electronics is updating the CAN driver for NETMF 4 0 and so the interface may change Check the documentation for further help Here is the code with detailed comments using System Threading using Microsoft SPOT using System using GHIElectronics Hardware namespace MFConsoleApplication1 public class Program public static void Main These numbers were calculated using the calculator on this link http www kvaser com can protocol index htm We used the very first value from the calculator output VMIMEMMMBlMlMIMMMPNIIPIHMMHMMBMPPWMMMMAPIMLIIIIIIIITITP BG PIT TTT Bitrate 250Kbps CLK 72 Mhz with BRP 12 6Mhz CAN clock 6Mhz 25 Kbps
49. Beginners Guide to C and NET Micro Framework August 11 2010 Rev 1 04 Copyright 2010 GHI Electronics LLC wwwW GHlIElectronics com wwwW TinyCLR com By Gus Issa electronics FREAKIN EASY Beginners guide to C and NET Micro Framework J Table of Contents 1 Change Lol 4 9 3 Interrupt Pott 39 SA FEZ PRIV oninurere 10 FEZ Domino and FEZ Mini 10 FEZ EOD6la aciei aai i acis Ear ids 12 12 Pulse Width Modulation iiic 25 Other WS vices ata id ad aloe 13 Sim latng PXIMOUL a ti re adi AT 6 Getting SUEDE au acce tia ner ta a cada 14 62 The Ereilitot cenena 14 Cro te 3 PARS a i caccia abi aana 14 Selecting Transporte eia citi cena caccia 16 SETUP RD MERE 17 Bib Hic DUMMEIS caosa er eine icio eee eee 18 6 3 Running on Hardware 19 BI What is MSN audio cauda n n 22 8 4 Win is Ea a eiii tides cu diese aine 22 Main is the Starting Point s 22 Commie MSec 23 HU RR 24 Varia DIGS si cicirccicaesetivaaivecssiessiwensveuesasanvetetees 25 INSSEMBNIES sedewsisiasavaseiecasshtesasansshetasatessites 27 Lr al PR UNE eT eT TREE 80 EN o Ee crn OEE OTe ore aCD TT oo 82 Lfd Ong Wife srania 83 Narcan ree tea teeta te catenins 84 Copyright 2010 GHI Electronics LLC Page 2 170 Beginners guide to C and NET Micro Framework J Native support on non standard display 99 DL Timne SOFVIDEB oaia aa 103
50. C and NET Micro Framework Cx Level 3J Can we make the for loop count only even numbers increment by two using System Threading using Microsoft SPOT using System namespace MFConsoleApplication1 public class Program public static void Main int i for i 2 i lt 10 i 1 2 Debug Print i i ToString The best way to understand for loops is by stepping in code and seeing how C will execute it 16 6 Switch Statement You will probably not use switch statement for beginner application but you will find it very useful when making large programs especially when handling state machines The switch statement will compare a variable to a list of constants only constants and make an appropriate jump accordingly In this example we will read the current DayOfWeek value and then from its value we will print the day as a string We can do all this using if statement but you can see how much easier switch statement is in this case using System Threading using Microsoft SPOT using System namespace MFConsoleApplication1 public class Program Copyright 2010 GHI Electronics LLC Page 73 170 Beginners guide to C and NET Micro Framework C Level 35 public static void Main DateTime currentTime DateTime Now int day int currentTime DayOfWeek switch day case Debug Print Sunday break
51. C Page 161 170 Beginners guide to C and NET Micro Framework Objects in Custom Heapg use the buffer lb Bytes 5 123 byte b lb Bytes 5 Dispose was called automatically J ig Copyright 2010 GHI Electronics LLC Page 162 170 Beginners guide to C and NET Micro Framework Thinking Small 33 Thinking Small Many NETMF developers come from the PC world They are used to write code that runs fine on a PC but then it will not run efficiently on an embedded device The PC can be 4GHz with 4GB of RAM NETMF devices have less than 1 of the resources available on a PC will cover different areas where you should always think small 33 1 Memory Utilization With limited RAM developers should only use what they really need PC programmers tend to make a large buffer to handle the smallest task Embedded Developers study what they need and only allocate the needed memory If am reading data from UART can very well use 100 byte buffer to read the data and 1000 byte buffer will work as well While am analyzing the code noticed that always read about 40 bytes from UART in my program loop do send a large buffer but only get back 40 bytes So why would want to use a buffer larger than 40 bytes Maybe will make it a bit large just in case but defiantly not 1000 bytes On some drivers the NETMF system does a lot of buffering internally For example file system UART USB drivers all have i
52. C using an RS232 lt gt USB cable no serial port on my PC also did place the MODE jumper and connected the USB cable from domino to this PC as well After placing the MODE jumper connecting the USB cable from FEZ Domino to a PC will not load any drivers on windows you will not hear the USB connect sound Finally we want to make sure we can ping the device using MFDeploy tool We did that before using USB and now we want to use serial Note that even though have FEZ Domino RS232 shield connected to my PC s USB port through the RS232 lt gt USB cable this is COM and not USB it is a virtual COM to be exact So open MFDeploy and select COM Waco ice PE ARE and then you will have a list of the Device available serial ports Select the one m connected to your device and click ping You should see TinyCLR Image File back If you don t then go back and Browse Deploy check your setup Copyright O 2010 GHI Electronics LLC Page 138 170 Beginners guide to C and NET Micro Framework USB Clieng 28 3 Mouse the Perfect Prank Here is the master plan You want to prank someone get it video taped and then send me the funny video This is how you do it Setup your FEZ to emulate a USB mouse then make the mouse move in a circle every few minutes bet you it will feel like there is a ghost on your machine The good news is that windows can have multiple mouse devices so FEZ will be hidden in the
53. Controller State Running else Debug Print Waiting to connect to PC Copyright 2010 GHI Electronics LLC Page 142 170 Beginners guide to C and NET Micro Framework USB Clieng cdc Write bytes 0 bytes Length Thread Sleep 1000 28 6 Mass Storage One of the great GHI unique features of USB client is supporting Mass Storage Class MSC This feature allows access to the connected media right from USB Let me explain this through some example A data logger application needs to save data to an SD card or USB memory When the user is done collecting data they can plug the USB data logger to the PC and now the PC can detect the device as a mass storage device The user can then transfer the files using standard operating system Think of the device as a memory card reader We can even enhance our logger where the USB client interface can be CDC to configure the device and later dynamically switch to MSC to transfer files Once very common question on GHI support is Why can t access the media while the media is also accessed externally from windows will try to explain this better A media is accessed though a class called PersistentStorage The PersistentStorage object can then be accessed by the internal file system or externally through the USB MSC Okay but why not both It can t be both because files systems cash a lot of info about the media to speed up file access time A
54. Debug a dele Microsoft SPOT Emulator Sample SampleEmulator exe Microsoft SPOT Emulator Sample SampleEmulator exe Microsoft SPOT Emulator Sample SampleEmulator exe The thread 0x2 has exited with code 0 0x0 Amazing 4 Ga Call Stack Ellmmediate Window z Output ir Error List If you now press F11 again the program will end and the emulator will exit Breakpoints Breakpoints are another useful feature when debugging code While the application is running the debugger checks if execution has reached a breakpoint If so the execution will pause Click the bar right to the left of the line that prints Amazing This will show a red dot which is the breakpoint El public static void Main 1 9i Debug Print Amazing F Now press F5 to run the software and when the application reaches the breakpoint the debugger will pause it as showing in the image below public static void Main Now you can step in the code using F11 or continue execution using F5 Copyright 2010 GHI Electronics LLC Page 18 170 Beginners guide to C and NET Micro Framework Getting Startedy 6 3 Running on Hardware Running NETMF applications on hardware is very simple Instructions can be very slightly different on every hardware This book uses FEZ for demonstration purposes but any other hardware will work similarly MFDeploy can Ping Before we use the hardware let us make sure it
55. Digital Input amp Outputy public static void Main OutputPort LED LED new OutputPort Cpu Pin FEZ Pin Digital LED true Thread Sleep Timeout Infinite See how much it is much easier We really do not need to know where the LED is connected Run the program and observe the LED It should be lit now Things are getting more exciting Blink an LED To blink an LED we need to set the pin high and delay for some time then we need to set it low and delay gain Its important to remember to delay twice Why It s because our eyes are too slow for computer systems If the LED comes on and then it turns back off very fast your eyes will not see that is was on for a very short time What do we need to blink a LED We learned how to make a while loop we know how to delay and we need to know how to set the pin high or low This is done by calling Write method in the OutputPort object Note that you can t use OutputPort Write This is very wrong because what output ports you are referring to Instead use LED Write which make complete scene Here is the code to blink the on board LED on FEZ Domino Mini using System using Microsoft SPOT using System Threading using Microsoft SPOT Hardware using GHIElectronics NETMF FEZ namespace MFConsoleApplication1 public class Program public static void Main OutputPort LED LED new OutputPort Cpu Pin FEZ Pin Digital LED true while
56. ED on OutputPort LED new OutputPort Cpu Pin FEZ Pin Digital LED true public static void Main TurnLEDOn we think that everythign is okay but it is not run the GC Debug GC true is LED still on Copyright 2010 GHI Electronics LLC Page 65 170 Beginners guide to C and NET Micro Framework Garbage Collectog To solve this we need a reference that is always available Here is the correct code using System using Microsoft SPOT using Microsoft SPOT Hardware namespace Test public class Program static OutputPort LED static void TurnLEDOn Turn the LED on LED new OutputPort Cpu Pin FEZ Pin Digital LED true public static void Main TurnLEDOn run the GC Debug GC true is the LED on Another good example is using timers NETMF provide a way to create timers that handle some work after a determined time If the reference for the timer is lost and the garbage collector had run the timer is now lost and it will not run as expected Timers are explained in later chapter Important note If you have a program that is working fine but then right after you see the GC running in the Output Window the program stops working or raises an exception then this is because the GC had removed an object that you need Again that is because you didn t keep references to the object you want to keep alive 15 2 Dispose The garbage collecto
57. F FEZ public class Program public static void Main blink LED FEZ_Components LED led new FEZ_Components LED FEZ_Pin Digital LED led StartBlinking 100 100 set to any random but valid time RealTimeClock SetTime new DateTime 2010 1 1 1 1 1 while true Thread Sleep 3000 blink LED for 3 seconds RealTimeClock SetAlarm RealTimeClock GetTime AddSeconds 10 Debug Print Going to sleep for 10 seonds sleep for 10 seconds Power Hibernate Power WakeUpInterrupt RTCAlarm Debug Print Good Morning Another option is to wake up on interrupt port You have to be careful with this because any interrupt on any pin will cause this wake up For example the WiFi module on FEZ Cobra internally uses one of the interrupt pins and so this will wake up the system You need to disable WiFi before hibernating This is not the only trick that you need to be aware of Look at the following or try it It will not work using System using System Threading using Microsoft SPOT using Microsoft SPOT Hardware using GHIElectronics NETMF Hardware using GHIElectronics NETMF Hardware LowLevel Copyright O 2010 GHI Electronics LLC Page 147 170 Beginners guide to C and NET Micro Framework Low Powery using GHIElectronics NETMF FEZ public class Program public static void Main blink LED FEZ_Components LED led new FEZ_Components LED FEZ_Pin Digital LED led StartBlinking 10
58. Files available on rootDirectory for int i 0 i files Length i Debug Print files i Debug Print Folders available on rootDirectory for int i 0 i lt folders Length i Debug Print folders i else Debug Print Storage is not formatted Format on PC with FAT32 FAT16 first Unmount sdPS UnmountFileSystem There is more than one way to open files will only cover FileStream objects This example will open a file and write a string to it Since FileStream will only take byte arrays we need to convert our string to byte array using System Threading using System Text using Microsoft SPOT using System IO using Microsoft SPOT IO using GHIElectronics NETMF IO namespace MFConsoleApplication1 public class Program static void Main check if SD is inserted Copyright O 2010 GHI Electronics LLC Page 114 170 Beginners guide to C and NET Micro Framework File System SD Card is inserted Create a new storage device PersistentStorage sdPS new PersistentStorage SD Mount the file system sdPS MountFileSystem Assume one storage device is available access it through NETMF string rootDirectory VolumeInfo GetVolumes 0 RootDirectory FileStream FileHandle new FileStream rootDirectory hello txt FileMode Create byte data Encoding UTF8 GetBytes This string will go in the
59. Framework Missing Topics 34 Missing Topics These are topics not covered by this book will give a very quick review to cover what the topic is about may expand this book to cover these topics in future 34 1 WPF Windows Presentation Foundation is a new and flexible way to create graphical user interface applications GHI s EMX and ChipworkX support WPF USBizi and FEZ do not support this feature 34 2 DPWS Device Profile for Web Services allows networked devices to be automatically detected and used on the network DPWS requires full NET sockets support 34 3 Extended Weak Reference Extended Weak Reference EWR allows developers to save little data in nonvolatile memory EWR is used more before File System was introduces to NETMF 34 4 Serialization Serialization is a way to convert an object to a series of bytes that represent that object An object Mike made from a Human type can be serialized into a byte array and then this data is transferred to another device The other device knows what a human type is but doesn t know anything about Mike It will take this data to construct a new object based on it and it now has a copy of the object Mike Using serialization in NETMF is a very bad idea unless you really needs it There are few methods that will help you in extract or place values in array You should be using these methods instead of serialization which is too slow 34 5 Runtime Loadable Procedures Runtime
60. Infinite 28 7 Custom Devices The GHI USB client Support even allows you to control the USB client in anyway you like This feature require good knowledge of USB If you do not know what is EndPoint and Pipe then do not attempt to create custom devices Also it is very important to have the device configured correctly the first time it is plugged into windows This is important because windows stores a lot of information in its registry So if you change the configuration of your device after you had it plugged into windows the first time then windows may not see the changes since it will be using the old configuration from its registry Basically stay away from USB Client Custom Devices unless you really have good reason to use them and you have very good knowledge in USB and in windows drivers Copyright O 2010 GHI Electronics LLC Page 144 170 Beginners guide to C and NET Micro Framework USB Clieng am not going to explain Custom Devices any further but just wanted to clear out why decided not to do so The standard built in classes explained earlier should be enough to cover most of your needs Copyright O 2010 GHI Electronics LLC Page 145 170 Beginners guide to C and NET Micro Framework Low Powe 29 Low Power Battery powered devices must limit power usage as much as possible Devices may lower the power consumption in many ways 1 Reduce processor clock 2 Shutdown the processor when system is idl
61. LED new OutputPort Cpu Pin FEZ Pin Digital LED true Port ResistorMode PullUp while true button state Button Read LED Write button state Thread Sleep 10 Button new InputPort Cpu Pin FEZ Pin Digital LDR false Can you make an LED blink as long as the button is pressed using System using Microsoft SPOT using System Threading using Microsoft SPOT Hardware using GHIElectronics NETMF FEZ namespace MFConsoleApplication1 public class Program public static void Main OutputPort LED InputPort Button LED new OutputPort Cpu Pin FEZ_Pin Digital LED true Button new InputPort Cpu Pin FEZ_Pin Digital LDR false Port ResistorMode PullUp while true while Button Read false Button is false when pressed LED Write true Thread Sleep 300 LED Write false Thread Sleep 300 Important note The is used to check for eqality in C This is different from which is Copyright 2010 GHI Electronics LLC Page 43 170 Beginners guide to C and NET Micro Framework C Level 2 used to assign values 10 2 if statement An important part of programming is checking some state and takes action accordingly For example if the temperature is over 80 turn on the fan To try the if statement with our simple setup we want to turn on the LED if the button is pressed Note this is the opposite from what we had before Since in our setup
62. Loadable Procedures RLP is a GHI exclusive feature that allows users to write native assembly C code for a device then load it and use it through managed C at runtime Native code is thousands times faster but it is not easy to manage Specific tasks like Copyright O 2010 GHI Electronics LLC Page 168 170 Beginners guide to C and NET Micro Framework Missing Topics calculating CRC that is a very processor intensive function are a perfect for for RLP The complete application is made using manage code C but then only CRC calculating method is written in native code assembly C 34 6 Databases A database stores data in a way where queering for data is easy Looking up a product or sorting numbers is very fast because of the indexing databases do internally 34 7 Touch Screen NETMF supports touch screens Touch screens are a good combination with TFT displays A developer can create a graphical application using WPF and then the user can control it using the touch screen 34 8 Events If we have a project that receives data from serial ports we need to read the serial port continuously We may not have any data but we do not know will we check for the data It will be more efficient if we can be notified if the serial driver had received data This notification comes from an event that fires when the serial driver receives data The same applies to interrupt ports covered before This book doesn t cover the creation of
63. REX SSD WriteCmdByte 0XA6 no inverse OPTREX SSD WriteCmdByte 0XB0 page addr OPTREX SSD WriteCmdByte 0X10 col OPTREX SSD WriteCmdByte 0X00 col int x 20 int y 50 int dx 2 int dy 3 Bitmap bb new Bitmap 128 64 byte bitmapbytes Font fnt Resources GetFont Resources FontResources small byte vram new byte 128 64 8 byte singleline new byte 128 while true bb Clear bb SetPixel 0 0 Color White bb SetPixel 0 2 Color White bb SetPixel 2 0 Color White bb SetPixel 2 2 Color White bb DrawText Rocks fnt Color White 20 45 bb DrawEllipse Color White x y 5 3 X dx y dy if x lt x gt 128 dx dx if y e l y gt 64 dy dy bitmapbytes bb GetBitmap Util BitmapConvertBPP bitmapbytes vram Util BPP Type BPP1 x128 for int 1 0 1 lt 8 1 OPTREX Locate 0 1 DC Write true Array Copy vram 1 128 singleline 0 128 Copyright O 2010 GHI Electronics LLC Page 101 170 Beginners guide to C and NET Micro Framework Displays SPI_port Write singleline Thread Sleep 1 Copyright 2010 GHI Electronics LLC Page 102 170 Beginners guide to C and NET Micro Framework Time Servicesy 21 Time Services In computer systems time can mean two things The system time which is the processor ticks is used to handle threads timing and all timing management in the sys
64. SharpBook Jens Kuhner excellent book on NET Micro Framework http www apress com book view 9781430223870 USB complete is an excellent book on USB http www lvr com usbc htm Wikipedia is my favorite place for information about everything http en wikipedia org wiki NET Micro Framework e NET Micro Framework main page on Microsoft s website http www microsoft com netmf 35 2 Disclaimer This is a free book only if you download it directly from GHI Electronics Use it for your own knowledge and at your own risk Neither the writer nor GHI Electronics is responsible for any damage or loss caused by this free eBook or by any information supplied by it There is no guarantee any information in this book is valid USBizi Embedded Master EMX ChipworkX RLP and FEZ are trademarks of GHI Electronics LLC Visual Studio and NET Micro Framework are trademarks or registered trademarks of Microsoft Corporation Copyright O 2010 GHI Electronics LLC Page 170 170
65. Thread Sleep Timeout Infinite static Thread WDTCounterReset static void WDTCounterResetLoop while true reset time counter every 3 seconds Thread Sleep 3000 Watchdog ResetCounter You may be thinking if the software locked up then how would the code that handles watchdog ever run On low level the watchdog is supported in hardware not software This means that the counter and the and reset mechanism is done inside the processor without the need for any software Limiting Time Critical Tasks Back to our vending machine example but this time we want to handle a different possible problem Since NETMF is not real time tasks can take longer than expected If a person stepped up to the vending machine and entered what they want to buy the machine will now turn a motor on which in turn will push the item out to the user Let us say this was timed so the motor has to be on for one second Now what if it happened that at the same time the motor is running another thread started using the SD card Let us also assume that the card had some problem which caused 3 second delay in reading the SD card The 3 seconds delay while the motor is running will result in 3 items being pushed out to the buyer but we only wanted to push one If we used watchdog and set it to one second then the user will have one item and when time is exceeding one second the vending machine will reset which will stop the motor from pushing m
66. able with digital circuits Copyright O 2010 GHI Electronics LLC Page 41 170 Beginners guide to C and NET Micro Framework C Level 2 10 C Level 2 10 1 Boolean Variables We learned how integer variables hold numbers In contrast Boolean variables can only be true or false A light can only be on or off representing this using an integer doesn t make a lot of sense but using Boolean it is true for on state and false for off state We have already used those variables to set digital pins high and low LED Write true To store the value of a button in a variable we use bool button state button state Button Read We also used while loops and we asked it to loop forever when we used true for the satement while true code here Take the last code we did and modify it to use a boolean so it is easier to read Instead of passing the Button state directly to the LED state we read the button state into button state boolean then we pass the button state to set the LED accordingly using System using Microsoft SPOT using System Threading using Microsoft SPOT Hardware using GHIElectronics NETMF FEZ namespace MFConsoleApplication1 public class Program public static void Main OutputPort LED InputPort Button bool button_state Copyright 2010 GHI Electronics LLC Page 42 170 Beginners guide to C and NET Micro Framework C Level B
67. annels start from 0 So using SPI1 in code is actually using SPIO on the processor using System Threading using System Text using Microsoft SPOT using Microsoft SPOT Hardware namespace MFConsoleApplication1 public class Program public static void Main SPI Configuration MyConfig new SPI Configuration Cpu Pin FEZmini Pin Di2x false 0 0 false true 1000 SPI SPI module SPI1 SPI MySPI new SPI MyConfig byte tx data new byte 10 byte rx data new byte 10 MySPI WriteRead tx data rx data Thread Sleep 100 Copyright 2010 GHI Electronics LLC Page 81 170 Beginners guide to C and NET Micro Framework Serial Interfacesg 17 3 12C I2C was developed by Phillips to allow multiple chipsets to communicate on a 2 wire bus in home consumer devices mainly TV sets Similar to SPI I2C have a master and one or more slaves on the same data bus Instead of selecting the slaves using a digital pin like SPI I2C uses software addressing Before data is transferred the master sends out a 7 bit address of the slave device it want communicate with It also sends a bit indicating that if the master wants to send or receive data The slaves that see its address on the bus will acknowledge its presence At this point the master and send receive data The master will start data transfers with start condition before it sends any address or data and then end it with stop condition I2C NETMF dri
68. asily upgrades to hardware such as Embedded Master Open source hardware design files Use existing shields and holder boards Based on the USBizi chipset ideal for commercial use FEZ Mini pin out compatible with BS2 FEZ Domino pin out compatible with Arduino When using FEZ the possibilities are endless There is a numerous amount of sensors that are ready to plug directly into the kits From LEDs and buttons to reflection and temperature sensors These book examples are made for FEZ devices In general the examples are still for NET Micro Framework so modifying it to run on any NETMF system should be an easy task Copyright O 2010 GHI Electronics LLC Page 11 170 Beginners guide to C and NET Micro Framework Selecting Device FEZ Cobra FEZ Cobra is an open source circuit board based on EMX module With multiple optional displays optional enclosure native graphics support native Ethernet support with SSL and megabytes of memory FEZ Cobra is ideal for those high end projects Not to forget that this is still FEZ so it is Freakin Easy to use iz Copyright O 2010 GHI Electronics LLC Page 12 170 Beginners guide to C and NET Micro Framework Selecting a Deviceg Other Devices GHI strives to deliver the latest technologies dynamically to its customer needs There is always something new at GHI so please visit www GHlIElectronics com and www TinyCLR com for the latest offer
69. ave the data with your own format which requires extra coding and debugging or better just use XML All GHI Electronics NETMF devices have built in XML reader and writer packer and un packer Here is an example XML file that will help in our data logger design xml version 1 0 encoding utf 8 lt NETMF_DataLogger gt lt FileName gt Data lt FileName gt lt FileExt gt txt lt FileExt gt lt SampleFreq gt 10 lt SampleFreq gt lt NETMF_DataLogger gt The previous XML example includes a root element and three child elements chose for the file to look that way but you can for example make all info to be root elements XML is very flexible sometimes too flexible actually Back to our example the root element NETMF_DataLogger contains three pieces of info that are important for our logger It contains the file name the file extension and a frequency of our saved data With this Copyright 2010 GHI Electronics LLC Page 128 170 Beginners guide to C and NET Micro Framework XML example the logger will create a file called Data txt and then will log data into that file 10 times every second Other important use for us Embedded developers is sharing data with the big system mean your PC Since PCs with all operating systems do support XML in a way or another you can send receive data from the PC using XML Spaces and layout do not mean anything to XML we humans need them to make things
70. back using System using System Threading using Microsoft SPOT using Microsoft SPOT Hardware using GHIElectronics NETMF USBClient using GHIElectronics NETMF Hardware using GHIElectronics NETMF FEZ public class Program public static void Main FEZ Components LED led new FEZ Components LED FEZ Pin Digital Di3 led StartBlinking 100 200 Check debug interface if Configuration DebugInterface GetCurrent Configuration DebugInterface Port USB1 throw new InvalidOperationException Current debug interface is USB It must be changed to something else before proceeding Refer to your platform user manual to change the debug interface Start Mouse USBC Mouse mouse USBClientController StandardDevices StartMouse Move pointer in a swirl const int ANGLE STEP SIZE 15 const int MIN CIRCLE DIAMETER 50 const int MAX CIRCLE DIAMETER 200 const int CIRCLE DIAMETER STEP SIZE 1 int diameter MIN CIRCLE DIAMETER int diameterIncrease CIRCLE DIAMETER STEP SIZE int angle 6 int factor Random rnd new Random int i 6 while true Copyright 2010 GHI Electronics LLC Page 139 170 Beginners guide to C and NET Micro Framework USB Clieng we want to do it every sometime randomely i rnd Next 5000 5000 between 5 and 10 seconds Debug Print Delaying for i ms Thread Sleep i i rnd Next 200 100 do it for a short time Deb
71. ble at http www programmersheaven com 2 CSharpBook 16 1 Byte We learned how int are useful to store numbers They can store very large numbers but every int consumes four bytes of memory You can think of a byte as a single memory cell A byte can hold any value from 0 to 255 It doesn t sound like much but this is enough for a lot of things In C bytes are declared using byte just like how we use int byte b 10 byte bb 1000 this will not work The maximum number that a byte can hold is 256 0 255 What s going to happen if we increment it to over 255 Incrementing 255 by one would overlap the value back to zero You will probably want to use int for most of your variables but we will learn later where bytes are very important when we start using arrays 16 2 Char To represent a language like English we need 26 values for lower case and 26 for upper case then 10 for numbers and maybe another 10 for symbols Adding all these up will give us a number that is well less than 255 So a byte will work for us If we create a table of letters numbers and symbols we can represent everything with a numerical value Actually this table already exists and it is called ASCII table So far a byte is sufficient to store all characters we have in English Modern computer systems have expanded to include other languages some used very complex non Latin characters The new characters are called Unicode characters
72. book is not meant to teach C but we will cover most of basics to help you get started So learning C is not boring will divide it into different levels so we will go on to do more fun things with NETMF then come back to C when necessary 8 1 What is NET Microsoft developed NET Framework to standardize programming Note how am talking about the full NET Framework and not the Micro Framework There are a set of libraries that developers can use from many programming languages The NET Framework run on PCs and not on smaller devices because it is a very large framework Also the full framework has many things that wouldn t be very useful on smaller devices This is how NET Compact Framework was born The compact framework removed unneeded libraries to shrink down the size of the framework This smaller version runs on Windows CE and smart phones The compact framework is smaller than the full framework but it is still too large for mini devices because of its size and because it require an operating system to run NET Micro Framework is the smallest version of those frameworks It removed more libraries and it became an OS independent Because of the similarity among these three frameworks almost same code can now run on PCs and small devices with little or no modifications For example using the serial port on a PC WinCE device or FEZ USBizi works the same way when using NET 8 2 What is C C and C are the most
73. both sides need to have a predetermined baud rate This is different on SPI where one of the nodes will send a clock to the other along with data This clock is used to determine how fast the receiver needs to read the data If you know electronics this is a shift register The clock is always transmitted from the master device The other device is a slave and it doesn t send a clock but receives a clock from the master So the master will transmit a clock on a SCK serial clock pin and will simultaneously transmit the data on MOSI Master Out Slave In pin The slave will read the clock on SCK pin and simultaneously read the data from MOSI pin So far this is a one way communication While data is transmitted in one direction using MOSI another set of data is sent back on MISO Master In Slave Out pin This is all done simultaneously clock send and receive It is not possible to only send or only receive with SPI You will always send a byte and receive a byte back in response Other data sizes are possible but bytes are most common NETMF supports 8 bit byte and 16 bit short data transfers Because of this master slave scheme we can add multiple slaves on the same bus where the master selects which slave it will swap the data with Note am using the word swap because you can never send or receive but you can send and receive swap data The master selects Copyright O 2010 GHI Electronics LLC Page 80 170 Beginners guide to C and
74. bug class object and who made the Print method that is in it Those calls are made by NETMF team at Microsoft They compile the code and give you an assembly to use it This way users are not messing with the internal code but they can use it At the top of the code used before we see using Microsoft SPOT This tells C that you want to use the namespace Microsoft SPOT Okay then what is a Copyright 2010 GHI Electronics LLC Page 27 170 Beginners guide to C and NET Micro Framework C Level J namespace Programs are split into regions spaces This is very important when programs are very large Every chunk of code or library is assigned a name for its space Programs with the same namespace see each other but if the name space is different then we can optionally tell C to use the other name space The name for our program s space is namespace MFConsoleApplication1 To use other name space like Microspft SPOT you need to add using Microsoft SPOT What is SPOT anyways Here is a short story A few years ago Microsoft privately started a project called SPOT They realized that this project was a good idea and wanted to offer it to developers They decided to change the product name to NET Micro Framework but they kept the code the same way for backward compatibility In short SPOT is NETMF Back to coding now try to remove or comment out using Microsoft SPOT and your code will n
75. c void Main create a thread handler Thread MyThreadHandler create a new thread object and assing to my handler MyThreadHandler new Thread MyThread start my new thread MyThreadHandler Start TILLITI AAAA Do anything else you like to do here Thread Sleep Timeout Infinite Copyright 2010 GHI Electronics LLC Page 33 170 Beginners guide to C and NET Micro Framework Digital Input amp Outputy 9 Digital Input amp Output On processors there are many digital pins that can be used as inputs or outputs When saying digital pins we mean the pin can be one or zero Important note Static discharge from anything including human body will damage the processor You know how sometimes you touch someone or something and you feel a little electronic discharge This little discharge is high enough to kill electronic circuits Professionals use equipments and take precautions handling the static charged in their body You may not have such equipment so just try to stay from touching the circuit if you don t have to You may also use an Anti static wrist band NETMF supports digital input and output pins through Microsoft SPOT Hardware assembly and name space Go ahead and add the assembly and namespace like we learned before Start Page Program cs x Solution Explorer Solution MFConsoleAp 2 X a 4s 2 4 MFConsoleApplicatic v 9 MyThread a el
76. case 1 Debug Print Monday break case 2 Debug Print Tuesday break case 3 Debug Print Wednsday break case 4 Debug Print Thursday break case 5 Debug Print Friday break case 6 Debug Print Saturday break default Debug Print We should never see this break One important note about switch statement is that it compares a variable to a list of constants After every case we must have a constant and not a variable We can also change the code to switch on the enumeration of days as the following using System Threading using Microsoft SPOT using System namespace MFConsoleApplication1 public class Program public static void Main Copyright O 2010 GHI Electronics LLC Page 74 170 Beginners guide to C and NET Micro Framework C Level 35 DateTime currentTime DateTime Now switch currentTime DayOfWeek 1 case DayOfWeek Sunday Debug Print Sunday break case DayOfWeek Monday Debug Print Monday break case DayOfWeek Tuesday Debug Print Tuesday break case DayOfWeek Wednesday Debug Print Wednsday break case DayOfWeek Thursday Debug Print Thursday break case DayOfWeek Friday Debug Print Friday break case DayOfWeek Saturday Debug Print Saturday break default Debug Print We should never see this break Try to step in the code to see how switch is handled in details Copy
77. ccessing the media simultaneously will definitely cause corruption to the media and therefor simultaneous access is not allowed Note that you can easily switch back and forth between internal file system and USB MSC This example code assumes an SD card is always plugged in It enables MSC showing the device I am using FEZ Domino as a card reader using System using System IO using System Threading using Microsoft SPOT using Microsoft SPOT Hardware using GHIElectronics NETMF USBClient using GHIElectronics NETMF IO using GHIElectronics NETMF Hardware namespace USBClient Example Copyright 2010 GHI Electronics LLC Page 143 170 Beginners guide to C and NET Micro Framework USB Clieng public class Program public static void Main Check debug interface if Configuration DebugInterface GetCurrent Configuration DebugInterface Port USB1 throw new InvalidOperationException Current debug interface is USB It must be changed to something else before proceeding Refer to your platform user manual to change the debug interface Start MS USBC MassStorage ms USBClientController StandardDevices StartMassStorage Assume SD card is connected PersistentStorage sd try catch sd new PersistentStorage SD throw new Exception SD card not detected ms AttachLun 0 sd enable host access ms EnableLun 0 Thread Sleep Timeout
78. come a card reader for the same SD memory card GHI s persistent storage class is used to handle mounting devices on the system This section will only cover using persistent storage device with internal file system 23 1 SD Cards First we need to detect the SD card insertion SD card connectors usually have a little switch internally that closes when a card is inserted In this example will assume the card is always inserted and there is no need to look for detection The example will list all files available in the root directory using System using System IO using System Threading using Microsoft SPOT using Microsoft SPOT IO using GHIElectronics NETMF IO namespace Test class Program public static void Main II uus SD Card is inserted Create a new storage device PersistentStorage sdPS new PersistentStorage SD Mount the file system sdPS MountFileSystem Copyright 2010 GHI Electronics LLC Page 113 170 Beginners guide to C and NET Micro Framework File Systemg Assume one storage device is available access it through Micro Framework and display available files and folders Debug Print Getting files and folders if VolumeInfo GetVolumes 0 IsFormatted string rootDirectory VolumeInfo GetVolumes 0 RootDirectory string files Directory GetFiles rootDirectory string folders Directory GetDirectories rootDirectory Debug Print
79. cts in Custom Heapg 32 Objects in Custom Heap Note that this topic is about very large memory allocation and so it doesn t apply to USBizi Managed systems like NETMF requires very complex memory management To limit the overhead on small systems NETMF heap only supports allocating objects up to 700KBs Larger objects are not possible Beginning in NETMF version 4 0 larger buffers can be allocated using a separate heap called custom heap Now you can create very large buffers and very large bitmaps Internally these objects are not in the standard managed heap but they are in custom heap This introduced a new important question How much memory is reserved for custom heap and how much for managed heap GHI provides APIs allowing you to set the size of each heap custom and managed using System using Microsoft SPOT Hardware using GHIElectronics NETMF Hardware class Program public static void Main set the heap size to 4MB if Configuration Heap SetCustomHeapSize 4 1024 1024 this will only take effect after resetting the system PowerState RebootDevice false TE xax you can now use large objects up to 4MB 32 1 Management of Custom Heap Unlike the regular heap which is fully managed the custom heap is managed but with few important points that need to be considered In order for objects in custom heap to be cleared automatically you must fulfill three requirements The object refe
80. d not designed to be embedded friendly GHI Electronics is the only company that offers WiFi option for its NETMF devices WiFi is designed to work with TCP IP stacks network sockets on NETMF and so it can only be used with systems that already support TCP IP like EMX and ChipworkX GHI s WiFi support uses ZeroG s ZG2100 and ZG2101 that use internal or external antennas respectively For prototyping the WiFi expansion board is a good start A As explained in earlier section USBizi FEZ can be used with modules with built in TCP IP stack and socket support like the SparkFun shield with WiFly modules from Roving Networks Copyright 2010 GHI Electronics LLC Page 122 170 Beginners guide to C and NET Micro Framework Networkingg 24 5 GPRS and 3G Mobile Networks EMX and ChipworkX have built in TCP IP stack and PPP support You can connect any standard modem and use it with few simple steps As far as USBizi a connection can be made to a mobile network using modems with built in TCP IP like SM5100B SparkFun Cellular shield with SM5100B is shown below Copyright O 2010 GHI Electronics LLC Page 123 170 Beginners guide to C and NET Micro Framework Cryptographyg 25 Cryptography Cryptography has been an important part of technology for long years Modern cryptography algorithms can be very resource hungry Since NETMF is made with little devices in mind the NETMF team had to be careful selecting what alg
81. der is in the System Xml namespace but the XML writer is in System Ext Xml To make life easier just include System Xml and MFDpwsExtensions assemblies whenever you need to get started with XML Also your code should include the two needed namespaces just like did in previous example Note When you try to add an assembly you will notice that there are two assemblies for XML the System Xml and System Xml Legacy Never use the legacy driver it is slow and needs a lot of memory It is there for older systems that doesn t have a built in support for XML All GHI Electronics NETMF devices have a built in XML support very fast and so you Copyright O 2010 GHI Electronics LLC Page 130 170 Beginners guide to C and NET Micro Framework XML should always use System Xml When running the example above we will see the output XML data at the end The data is correct but it is not formatted to be human friendly Note that we are reading and writing XML files on a very small system so the less info spaces formatting the better it is So it is actually better not to have any extra spaces or formatting but for the sake of making things look pretty we will add new lines as follows using System IO using System Xml using System Ext Xml using Microsoft SPOT public class Program public static void Main 1 MemoryStream ms new MemoryStream XmlWriter xmlwrite XmlWriter Create ms xmlwrite WriteProce
82. e All hardware PWM signals share the same clock Changing the frequency on one will change it on other channels but duty cycle is independent Copyright O 2010 GHI Electronics LLC Page 56 170 Beginners guide to C and NET Micro Framework Pulse Width Modulationg Simulating PWM PWM pins are controlled internally inside the processor using a special PWM hardware This means the hardware internally will toggle the pin The processor only needs to set some registers and then no processor interaction is needed at all to generate the PWM signal GHI s NETMF devices provide an OutputCompare class Through this class a user can generate about any signal including PWM Note that this is done in software so it is better to use the PWM class is possible Why When you use the PWM class then the signal for PWM is generated using hardware and the processor doesn t need to do anything On the other hand when you use OutputCompare to generate PWM then the processor need to keep track of time and toggle the PWM pin at specific time constants The servo motor example provided on www TinyCLR com uses OutputCompare The advantage of this is that you can use any pin to control a servo It is better to use PWM to control the servo but then you will only be able to use the PWM specific pins Controlling Servo Motors and Fine tune the PWM We have learned how to control the amount of energy using PWM There are other good uses for PWM such as controlling
83. e keep peripherals and interrupts running 3 Shutdown specific peripherals 4 Hibernate the system A NETMF device may optionally support any of these methods Consult with your device s user manual to learn more about what is directly supported In general all GHI NETMF devices shutdown the processor when in idle state For example this will reduce the power on FEZ Rhino by about 45mA You really do not have to do anything special as soon as the system is idle the processor is automatically shut off while interrupts and peripherals are still active Also all peripherals ADC DAC PWM SPI UART are disabled by default to lower power consumption They are automatically enabled once they are used If all that is not enough you can completely hibernate the system Just remember that when the system is hibernating it is not executing and peripherals are not functional For example data coming in on UART will NOT wake up the system You will simply lose the incoming data Waking up from hibernate is a system dependent feature but usually specific pin s can be toggled to wake the system up Note GHI realized that the standard NETMF power mode is not suitable for hibernate so a GHI specific method is implemented to handle the system hibernation Important Note When the device is in hibernation USB stops working You can t step in code or access the device If your program always puts the device in sleep then you will not be able to l
84. e PC A hacker can see the encrypted data and can see the public key but without the private key decrypting the data is near impossible Finally system A can decrypt the data with its private key By the way this is how secure websites work NETMF devices can t generate keys The keys are generated on a PC using a tool called MetaDataProcessor Open the command prompt and enter this command cd C Program Files x86 Microsoft NET Micro Framework v4 0 Tools Note that you may need to change this folder depending on where you have installed NET Micro Framework Generate the keys using the following MetadataProcessor exe create key pair c private bin c public bin The keys are in binary but the tool can convert the keys to readable text using these commands MetadataProcessor exe dump key c public bin gt gt c public txt Copyright 2010 GHI Electronics LLC Page 125 170 Beginners guide to C and NET Micro Framework Cryptographyg MetadataProcessor exe dump_key c private bin gt gt c private txt Now copy the key to our example program Note that the public key always starts with 1 0 1 and the rest are zeros We can use this info to optimize our code as showing using System using System Text using Microsoft SPOT using Microsoft SPOT Cryptography public class Program public static void Main this is shared between public and private keys byte module new byte 0x17 0xe5 0
85. e can be an optional variable type If no returned value is used then we replace the variable type with void The return keyword is used to return values at the end of a method Here is a very simple method that returns the sum of two integers int Add int var1 int var2 int var3 var3 vari var2 return var3 We started the method with the return value type int followed by the method name Then we have the argument list Arguments are always grouped by parenthesis and separated by commas Copyright O 2010 GHI Electronics LLC Page 47 170 Beginners guide to C and NET Micro Framework C Level 2 Inside the Add method a local integer variable has been declared that is var3 Local variables are created inside a method and die once we exit the method After that we add our two variables and finally return the result What if we want to return a string representing the sum of two numbers Remember that a string containing number 123 is not the same as an integer containing 123 An integer is a number but a string is an array or characters that represent text or numbers To humans these are the same things but in computer world this is totally different Here is the code to return a string string Add int vari int var2 int var3 var3 vari var2 string MyString MyString var3 ToString return MyString You can see how the returned type was changes to string We couldn t
86. e processors that run on 3 3V Copyright O 2010 GHI Electronics LLC Page 37 170 Beginners guide to C and NET Micro Framework Digital Input amp Output so the highest voltage the pin should see is 3 3V This is true for ChipworkX but for Embedded Master and USBizi those processors are 5V tolerant This means that even though the processor runs on 3 3V it is capable of tolerating up to 5V on its inputs Most digital chips that you would be interfacing to are 5V Being 5V tolerant allows us to use any of those digital circuits with our processor Note FEZ is based on USBizi and so it is 5V tolerant Important note 5V tolerant doesn t mean the processor can be powered off 5V Always power it with 3 3V Only the input pins can tolerate 5V on them InputPort object is used to handle digital input pins Any pin on the processor GHI uses can be input or output but of course not both Unconnected input pins are called floating You would think that unconnected input pins are low but this is not true When a pin is an input and is not connected it is open for any surrounding noise which can make the pin high or low To take care of this issue modern processors include and internal weak pull down or pull up resistors that are usually controlled by software Enabling the pull up resistor will pull the pin high Note that the pull up resistor doesn t make a pin high but it pulls it high If nothing is connected then the pin is high by default
87. ead Sleep 100 Copyright O 2010 GHI Electronics LLC Page 103 170 Beginners guide to C and NET Micro Framework Time Servicesy To use the RTC hardware we first need to check if the RTC hardware has the valid time or not Maybe this is a new battery or the new system and the RTC has not been set yet If RTC has a valid time then we can read the RTC hardware and use that to set the NETMF system time software If time is not valid then you will need to set the RTC to the correct time using System using Microsoft SPOT Hardware using GHIElectronics NETMF Hardware public class Program public static void Main To keep track of time set it at the beginning of your application from the RTC If it was NOT set before and currently running using the battery not exhausted set it to a fixed time if RealTimeClock IsTimeValid false RealTimeClock SetTime new DateTime 2010 03 01 12 0 Utility SetLocalTime RealTimeClock GetTime 21 2 Timers Micro Framework includes 2 timer classes Timer and ExtendedTimes Timer class is the same one included in full framework where ExtendedTimer is specific to NETMF with extra functionality For basic beginner projects suggest you keep on using threading before getting into timers will only provide an example in this book Our example will create a timer that will run after five seconds and then it will keep firing eve
88. easier to read The previous example can be stored without the spaces and layout like this xml version 1 0 encoding utf 8 NETMF DataLogger FileName Data FileName FileExt txt FileExt SampleFreq 10 SampleFreq NETMF DataLogger See why spaces are important to us human being You can also add comments inside XML files comments do not mean anything to XML but can help in manual reading of the files lt xml version 1 0 encoding utf 8 gt lt This is just a comment gt NETMF DataLogger lt FileName gt Data lt FileName gt lt FileExt gt txt lt FileExt gt lt SampleFreq gt 10 lt SampleFreq gt lt NETMF_DataLogger gt Finally XML support attributes An attribute is an extra info given to an element But why do you need an attribute if you can add another element to describe this extra information You really do not need to use attributes and would say if you do not have a good reason then just do not use them will no be explaining attributes in this book 26 2 Creating XML GHI Electronics NETMF devices support reading and writing XML format Reading and writing XML files work over streams which means any stream you already have or implement can work with XML For example we will use the built in MemoryStream and FileStream but you can create your own stream as well which is not covers in this book This code shows how to make an XML document in memor
89. ected Thread Sleep 1000 17 5 CAN Controller Area Network is a very common interface in industrial control and automotive CAN is very robust and works very well in noisy environments at high speeds All error checking and recovery methods are done automatically on the hardware TD Transmit Data and RD Receive Date are the only two pins needed These pins carry out the digital signal that need to be converted to analog before it is on the actual wires using the physical layer Physical layers are sometimes called transceivers There are many kinds of physical layers but the most commonly used is high speed dual wire that uses twisted pair for noise immunity This transceiver can run at up to 1Mbps and can transfer data on very long wires if low bit rate is used Data can be transferred between nodes on the bus where any node can transfer at any time and all other nodes are required to successfully receive the data There is no master slave in CAN Also all nodes must have a predefined bit timing criteria This is much more complicated that calculating a simple baud rate for UART For this reason many CAN bit rate calculators are available The CAN peripheral of Embedded Master is same as the popular SJA1000 A quick Internet search for SJA1000 should result in more than one free calculator In short this is a simple way to calculate the bit timing 1 Divide the system clock 72Mhz to get an appropriate clock for the C
90. eee 170 35 2 DISCIAIOE c5 cascos itis coca 170 Copyright O 2010 GHI Electronics LLC Page 3 170 Beginners guide to C and NET Micro Framework Change Logg 1 Change Log Version 1 04 Corrected typos Changed VS2008 to VS2010 Added a note about 1040 board in expanding IO section Updated watchdog section disable is not allowed Version 1 03 Corrected typos Revised all the font type in sample code boxes Revised a paragraph 16 1 Byte Rewrote Missing Topics Added Watchdog section Added Low Power Section Added important note to Garbage Collector Added a new Output messages subsection to Garbage Collector Added other devices in GHI offers Changed graphics section to point out the new SPI displays on www TinyCLR com The index now has two rows Version 1 02 Corrected typos Updated to use VS2010 instead of VS2008 Updated 4 0 to 4 1 and put new link to 4 1 download Added a note about using glitch filters with interrupt capable pins Rewrote the Real Time Clock section Added new USB Client section Copyright O 2010 GHI Electronics LLC Page 4 170 Beginners guide to C and NET Micro Framework About the Bookg 2 About the Book 2 1 Intended Audience This book is for beginners wanting to learn NET Micro Framework No prior knowledge is necessary The book covers NET Micro Framework Visual C and even covers C If you re a programmer a hobbyist or an engineer you will find a good deal of i
91. ent port is used by your end application The good news is that you only need the serial interface in the development stage but when you deploy the product the serial port is no longer needed For example you may use the RS232 shield on FEZ Domino in development stage but then you do not need it when you are done debugging Now you have COM1 connected to your device and want to use that for debugging instead of USB The next step is to configure the device to use serial for debugging This is a device specific so you need to check your device s user manual For example if you are using FEZ Copyright O 2010 GHI Electronics LLC Page 137 170 Beginners guide to C and NET Micro Framework USB Clieng Domino there is jumper labeled MODE that you can place to select serial debugging If you are using FEZ Cobra then the pin LMODE need to be connected to 3 3V to select serial debugging Remember that once you connect the pin high or low then you can no longer use it in your application For example the MODE pin on FEZ Domino is the same pin used for LED and it is also a PWM pin Once you short the pin to ground through the jumper you should never attempt to use this pin never try to use the LED or you may damage your device 28 2 The Setup Okay enough talking and let us set up am using FEZ Domino with RS232 shield but you can use any device of your choice have the RS232 shield plugged into FEZ Domino and also connected to my P
92. er it Luckily NETMF includes a glitch filter built internally so we never need to worry about this When we enable an input pin we have the option of enabling the glitch filter The second argument when creating an InputPort is a boolean indicating if the glitch filter to be enabled or not For using switches you probably would want this to always be true Button new InputPort Cpu Pin FEZ Pin Digital LDR true Port ResistorMode PullUp The glitch filter time can be changed as follows TimeSpan ts new TimeSpan 0 0 0 0 200 200ms Microsoft SPOT Hardware Cpu GlitchFilterTime ts Important note Glitch filter only works on interrupt capable pins If you try to use InputPort with glitch filter is set to true and you see an exception then most likely you are using a pin that is not interrupt capable Copyright O 2010 GHI Electronics LLC Page 60 170 Beginners guide to C and NET Micro Framework Analog input amp output 14 Analog input amp output Analog pins are usually multiplexed with digital pins Some of the processor pins can be digital and analog as well but not both at the same time 14 1 Analog Inputs Digital input pins can only read high and low one or zero but analog pins can read the voltage level There are limitations on voltages that can be applied to analog inputs For example FEZ analog input can read voltages anywhere between zero and 3 3V When the pins are digital
93. eresting want to print numbers 1 to 10 OK we know how to make a variable and we know how to increment it but how to print a number on the debug output window Simply giving MyVar to Debug Print will give you error and it won t work This is because Debug Print will only accept strings not integers How do we convert integer variable ToString It is very simple call MyVar ToString That was easy using System using Microsoft SPOT namespace MFConsoleApplication1 public class Program public static void Main int MyVar MyVar while MyVar 10 1 MyVar 3 Debug Print MyVar ToString Jj Copyright 2010 GHI Electronics LLC Page 26 170 Beginners guide to C and NET Micro Framework C Level ly Last thing to add is that we want to make the program print Count 1 Count 2 Count 9 Count 10 This can be easily done by adding strings Strings are added using the symbol just like how you would add any numbers Try the following code using System using Microsoft SPOT namespace MFConsoleApplication1 public class Program public static void Main int MyVar MyVar while MyVar 10 MyVar Debug Print Count MyVar ToString Assemblies Assemblies are files containing compiled assembled code This allows developer to use the code but they don t have access to the source code We had already used Debug Print before Who made the De
94. es select Console Application Copyright 2010 GHI Electronics LLC Page 14 170 Beginners guide to C and NET Micro Framework Getting Startedg Project types Templates Visual C Visual Studio installed templates Micro Framework e re oo A e AJA S Class Library Console Device Window Application Emulator Application My Templates Search Online Te MFConsoleApplication1 Click the OK button and you will have a new project that is ready to run The project has only one C file called Program cs which contains very few lines of code The file is shown in Solution Explorer window If this window is not showing then you can open it by clicking View gt Solution Explorer from the menu using System using Microsoft SPOT namespace MFConsoleApplication1 public class Program public static void Main Debug Print Resources GetString Resources StringResources String1 I Copyright O 2010 GHI Electronics LLC Page 15 170 Beginners guide to C and NET Micro Framework Getting Started For simplicity change the code as it look like the listing below using System using Microsoft SPOT namespace MFConsoleApplication1 public class Program public static void Main Debug Print Amazing Selecting Transport Don t worry if you do not understand the code will explain it later For now we
95. events but we already seen how they are used in interrupt ports and used in using a mouse with USB host support 34 9 USB Host Raw We have learned how to access some USB devices using the GHI exclusive USB host support GHI allows users to write managed drivers for almost any USB device Accessing USB directly is considered a very advanced feature and is left out of this book This is a project that uses USB raw access to read an XBOX Controller http www microframeworkprojects com index php title2Xbox Controller Another interesting project is the NXT drivers allowing users to control LEGO NXT Mindstorm right from C and Visual Studio http www microframeworkprojects com index php title NXT Mindstorm Copyright O 2010 GHI Electronics LLC Page 169 170 Beginners guide to C and NET Micro Framework Final Wordsg 35 Final Words If you found this book useful and it saved you few minutes of research then have accomplished what had in mind very much thank you for your downloading and reading this book 35 1 Further Reading This book only covers the basics of C and NET Micro Framework This is a list of some resources to learn more e My blog is always a good place to visit http tinyclr blogspot com The Micro Framework Project website is an excellent resource http www microframeworkprojects com A good and free eBook to continue learning about C is available at http www programmersheaven com 2 C
96. ework as NETMF Copyright 2010 GHI Electronics LLC Page 6 170 Beginners guide to C and NET Micro Framework Portingy 4 Porting There are two sides of working with NETMF porting it and using it For example writing a JAVA game on a cell phone is much easier than placing the JAVA virtual machine JVM ona phone The phone manufacture did all the work of porting JAVA to their phone and game programmers can use it with less effort NETMF works the same way porting is not easy but using it is very easy NETMF can be split in two major components the core and HAL Hardware Access Layer The core libraries are made so they are hardware independent Usually no modifications are needed on the core libraries Developers need to make their own HAL to run NETMF ona device 4 1 GHI Standard Offers We work very close with our customers to make sure everything is flowing as needed GHI offers many exclusive features that come standard and free with our products USB host database PPP RLP Wi Fi one wire etc Dedicated and free support is available through email phone and forum Copyright 2010 GHI Electronics LLC Page 7 170 Beginners guide to C and NET Micro Framework Selecting a Devicey 5 Selecting a Device GHI Electronics offers an extensive range from the very basic to the very advance e ChipworkX EMX e USBizi FEZFamily e FEZ Domino and FEZ Mini FEZ Rhino e FEZ Cobra and many more
97. file write the data and close the file FileHandle Write data 0 data Length FileHandle Close if we need to unmount sdPS UnmountFileSystem TE as Thread Sleep Timeout Infinite Verify the file if it is on the card using a PC and memory card reader if you like Now we want to open the same file and read the string we stored earlier using System Threading using System Text using Microsoft SPOT using System IO using Microsoft SPOT IO using GHIElectronics NETMF IO namespace MFConsoleApplication1 public class Program static void Main 1 check if SD is inserted SD Card is inserted Create a new storage device PersistentStorage sdPS new PersistentStorage SD Copyright O 2010 GHI Electronics LLC Page 115 170 Beginners guide to C and NET Micro Framework File System Mount the file system sdPS MountFileSystem Assume one storage device is available access it through NETMF string rootDirectory VolumeInfo GetVolumes RootDirectory FileStream FileHandle new FileStream rootDirectory hello txt FileMode Open FileAccess Read byte data new byte 100 write the data and close the file int read count FileHandle Read data 0 data Length FileHandle Close Debug Print The size of data we read is read count ToString Debug Print Data from file Debug Print data ToString if we need
98. font NETMF supports creating fonts using TFConvert tool will not cover the use of TFConvert so we will use one of the available fonts When we draw using a bitmap object we are actually drawing on the object on memory nothing is visible on the screen To transfer a bitmap object from memory to the screen we need to flush the bitmap object An important note here is that flush will only work if the size of the bitmap is exactly the same size of the screen If you have an image size 128x128 pixels and want to display it on the screen we first need to create a new bitmap object with the size of the screen then create a second bitmap object for the smaller image Draw the smaller image on the large one and then flush To eliminate confusion always have a one bitmap object called LCD and then everything gets drawn on this object We will run all these tests on the emulator instead of hardware as your hardware may not support native graphics using System Threading using Microsoft SPOT using System using Microsoft SPOT Presentation using Microsoft SPOT Presentation Media namespace MFConsoleApplication1 x public class Program public static void Main 1 Bitmap LCD new Bitmap SystemMetrics ScreenWidth SystemMetrics ScreenHeight clears the memory and not the display LCD Clear draw on memory LCD DrawLine Colors Green 1 10 10 40 40 transfer the bitmap memory to the actual display LCD Flush
99. g GHIElectronics NETMF FEZ public class Program public static void Main static void LDR OnInterrupt uint data1 uint data2 DateTime time blink LED FEZ Components LED led new FEZ Components LED FEZ Pin Digital LED led StartBlinking 100 100 setup the interrupt pin InterruptPort LDR new InterruptPort Cpu Pin O false Port ResistorMode PullUp Port InterruptMode InterruptEdgeLow LDR OnInterrupt new NativeEventHandler LDR_OnInterrupt while true Thread Sleep 3000 blink LED for 3 seconds sleep Power Hibernate Power WakeUpInterrupt InterruptInputs we get here when we wakeup empty for now This example will blink an LED when up and then when the LDR button is pressed the system will go into deep sleep for 10 se This is an example for FEZ Domino USBizi that will go into deep sleep and wake up when using using using using using using using public class Program System System Threading Microsoft SPOT Microsoft SPOT Hardware GHIElectronics NETMF Hardware GHIElectronics NETMF Hardware LowLevel GHIElectronics NETMF FEZ Copyright O 2010 GHI Electronics LLC Page 150 170 Beginners guide to C and NET Micro Framework Low Powery public static void Main blink LED FEZ_Components LED led new FEZ_Components LED FEZ_Pin Digital LED led StartBlinking 100 100 setup the interrupt pin InputPort LDR new InputPort Cpu P
100. ght 2010 GHI Electronics LLC Page 160 170 Beginners guide to C and NET Micro Framework Objects in Custom Heapg 32 2 Large Bitmaps Bitmaps larger than 750KB 2 are automatically allocated on the custom heap For example a 800x480 bitmap will need 800x480x4 bytes that is about 1 5MB This large bitmap is on the custom heap and so you should always dispose it when you are done using it or utilize the using statement using System using Microsoft SPOT using Microsoft SPOT Presentation Media class Program public static void Main using Bitmap largeBitmap new Bitmap 800 480 assumign we have a display that is 800x480 draw a circle largeBitmap DrawEllipse Colors Green 100 100 10 10 draw other things HI ws largeBitmap Flush flush the Bitmap object to the display once we are here largeBitmap Dispose was automatically called VE aia 32 3 LargeBuffer We already used LargeBuffer in earlier example Only use this if you need to allocate a buffer that is larger than 750KB On an embedded system you shouldn t need or use such very large buffers Although not recommended this is available in case it is needed using System using Microsoft SPOT Hardware using GHIElectronics NETMF Hardware class Program public static void Main allocate a 1MB buffer using LargeBuffer lb new LargeBuffer 1024 1024 Copyright 2010 GHI Electronics LL
101. hread Sleep BYTE TIME MS public void PutC char c private void SendCommand byte cmd SendByte byte c SendByte OxFE SendByte cmd buffer currentBufferIndex currentStateTiming buffer currentBufferIndex currentStateTiming oc Set false buffer 0 currentBufferIndex false Copyright O 2010 GHI Electronics LLC Page 88 170 Beginners guide to C and NET Micro Framework Output Compare public void Print string str for int i 0 i str Length i PutC str i public void ClearScreen SendCommand CLR_DISP public void CursorHome SendCommand CUR HOME public void SetCursor byte row byte col SendCommand byte SET_CURSOR row lt lt 6 col public void MoveLeft SendCommand Move_CURSOR_LEFT public SerialLCD FEZ Pin Digital pin BYTE TIME MS int Math Ceiling double BIT TIME US MAX TIMINGS BUFFER SIZE 1000 oc new OutputCompare Cpu Pin pin true MAX TIMINGS BUFFER SIZE Initilaize LCD SendCommand DISP ON SendCommand CLR DISP Copyright 2010 GHI Electronics LLC Page 89 170 Beginners guide to C and NET Micro Framework Loading Resources 19 Loading Resources A resource is a file that is included with the application image If our application depends on a file image icon sound then we may want to add this file to the application resources Application can read the fi
102. ical can be 20ms to 30ms then will just use a period of 20ms This will result in a low time that will vary slightly but again this is not important to servos What is important is the high pulse which must be between 1 25ms to 1 75ms One last thing and we are done SetPulse accepts value in nanoseconds but we have value in milliseconds One millisecond is the equivalent of 1 000 000 a million nanoseconds Finally here is the example using System using System Threading using Microsoft SPOT using GHIElectronics NETMF Hardware using GHIElectronics NETMF FEZ class Program public static void Main 1 PWM servo new PWM PWM Pin FEZ Pin PWM Di5 while true degrees 20ms period and 1 25ms high pulse servo SetPulse 20 1000 1000 1250 1000 Thread Sleep 1000 wait for a second 90 degrees 20ms period and 1 50ms high pulse servo SetPulse 20 1000 1000 1500 1000 Thread Sleep 1000 wait for a second 180 degrees 20ms period and 1 75ms high pulse servo SetPulse 20 1000 1000 1750 1000 Thread Sleep 1000 wait for a second Thread Sleep 1 Copyright 2010 GHI Electronics LLC Page 58 170 Beginners guide to C and NET Micro Framework Pulse Width Modulationg 12 1 Piezo Piezoelectric devices are a low cost way of adding tones and beeps to your design They generate sounds one supplied with a frequency PWM hardware is perfect for generating frequencies and so the
103. in MemoryStream ms new MemoryStream XmlWriter xmlwrite XmlWriter Create ms xmlwrite WriteProcessingInstruction xml version 1 0 encoding utf 8 xmlwrite WriteComment This is just a comment xmlwrite WriteRaw r n xmlwrite WriteStartElement NETMF_DataLogger root element xmlwrite WriteString r n t xmlwrite WriteStartElement FileName child element xmlwrite WriteString Data xmlwrite WriteEndElement xmlwrite WriteRaw r n t xmlwrite WriteStartElement FileExt xmlwrite WriteString txt xmlwrite WriteEndElement xmlwrite WriteRaw r n t xmlwrite WriteStartElement SampleFeq xmlwrite WriteString 10 xmlwrite WriteEndElement xmlwrite WriteRaw r n xmlwrite WriteEndElement end the root element xmlwrite Flush xmlwrite Close display the XML data byte byteArray ms ToArray char cc System Text UTF8Encoding UTF8 GetChars byteArray Copyright 2010 GHI Electronics LLC Page 132 170 Beginners guide to C and NET Micro Framework XML string str new string cc Debug Print str read xml MemoryStream rms new MemoryStream byteArray XmlReaderSettings ss new XmlReaderSettings ss IgnoreWhitespace true ss IgnoreComments false XmlException XmlExceptionErrorCode XmlReader xmlr XmlReader Create rms ss while xmlr EOF xmlr Read switch xmlr NodeType
104. in 0 true Port ResistorMode PullUp while true Thread Sleep 3000 blink LED for 3 seconds sleep Power Hibernate Power WakeUpInterrupt InterruptInputs we get here when we wakeup Finally you can wake up on more than one events For example you can wake up if a button is pressed or the alarm is fired Power Hibernate Power WakeUpInterrupt InterruptInputs Power WakeUpInterrupt RTCAlarm Copyright O 2010 GHI Electronics LLC Page 151 170 Beginners guide to C and NET Micro Framework Watchdog 30 Watchdog In embedded system world devices are usually always running and with no user interaction So if something went wrong it would be very beneficial if we have an automatic reset button Watchdog is your reset button System Execution Recovery Assume you are making a smart vending machine that reports its inventory over the network If your code raises an exception that wasn t handled properly then your program will end Program ended means the vending machine no longer work Someone will have to drive to the vending machine to reset it or better just use watchdog When you enable the watchdog you give it a timeout to reset after Then you keep resetting the watchdog timer periodically If the system locks up then the watchdog counter will reach the timeout which in turn will reset the system Important note GHI realized that the built in watchdog in NETMF is not what custome
105. ing on it is a scaled down version of Embedded Master It includes all features except networking TCP IP and PPP and native graphics Even though these features are missing USBizi can be connected to a network using TCP IP chipsets like WlZnet and can run simple displays There are example projects already provided showing how USBizi can be networked and can display graphics Copyright O 2010 GHI Electronics LLC Page 9 170 Beginners guide to C and NET Micro Framework Selecting a Devicey 5 4 FEZ Family FEZ Domino and FEZ Mini FEZ Domino and FEZ Mini are very small open source boards targeted for beginners They are based on the USBizi chipset FEZ offers many peripherals such as USB host and SD interface not available with many hobbyist targeted boards Even though FEZ is targeted for beginners it s also a low cost starting point for professionals wanting to explore NETMF FEZ stands for Freakin Easy Copyright 2010 GHI Electronics LLC Page 10 170 Beginners guide to C and NET Micro Framework Selecting a Devicey FEZ offers many features not found in Arduino BASIC STAMP and others Based on Microsoft s NET Micro Framework Runs on a 72Mhz NXP ARM processors Supports run time debugging breakpoints variable inspection stepping etc Uses Visual Studio 2008 C Express Edition for development Advanced capabilities like FAT USB device and USB host E
106. ject included false in it This is used for glitch filter This will be explained later Also it maybe is confusing how we passed the state of an InputPort to set an OutputPort We will revisit this in the next section 9 3 Interrupt Port If we want to check the status of a pin we will always have to check its state periodically This wastes processor time on something not important You will be checking the pin maybe a million times before it is pressed Interrupt ports allows us to set a method that will be executed when the button is pressed when pin is low for example We can set the interrupt to fire on many state changes on the pin when pin is low or maybe when it is high The most common use is the on change The change from low to high or high to low creates a signal edge The high edge occurs when the signal rises from low to high The low edge happen when the signal falls from high to low In the example below am using both edges so our method IntButton Onlnterrupt will automatically run whenever the state of our pin changes using System using Microsoft SPOT using System Threading using Microsoft SPOT Hardware using GHIElectronics NETMF FEZ namespace MFConsoleApplication1 public class Program this moved out here so it can be used by other methods static OutputPort LED public static void Main LED new OutputPort Cpu Pin FEZ Pin Digital LED true the pin will generate
107. ke a simple web server or telnet connection for configuration or data transfer This is perfect for small systems with limited memory and low resources like USBizi FEZ The module does everything for you just send and receive data serially If you are implementing a web server that provides some values like temperature and humidity then this is all you need and can be easily implemented using USBizi FEZ at a very low cost An easy prototype is done by connecting the WiFly shield to FEZ Domino The SparkFun WiFly shield is showing in the image to the right The negative side about using these simple modules is that you are limited very few sockets very few connections What if you need more What if you want to implement SSL secure sockets For those you will need a WiFi module that doesn t handle TCP IP internally The TCP IP work will need to be done outside the module This is where devices like EMX and ChipworkX come in These devices are powerful with a lot of resources They have built in TCP IP stack with SSL HTTP DHCP etc So connecting module like ZeroG to EMX or ChipworkX will empower the device with full blown and secure WiFi connection Copyright O 2010 GHI Electronics LLC Page 120 170 Beginners guide to C and NET Micro Framework Networkingg What about GPRS and 3G modems The same applies to these modules Some have built in sockets like SM5100B but others work over PPP just like any PC modem like Telit module
108. l 2 10 9 Enumeration An Enumeration is very similar to constant Let s say we have a device that accepts four commands those are MOVE STOP LEFT RIGHT This device is not a human and so these commands are actually numbers We can create constants variables for those four commands like the following const int MOVE 1 const int STOP 23 const int RIGHT 3 const int LEFT 4 now we can send a command SendCommand MOVE SendCommand STOP The names are all upper case because this is how programmers usually name constants Any other programmer seeing an upper case variable would know that this is a constant The code above is okay and will work but it will be nicer if we can group those commands enum Command MOVE 1 STOP 2 RIGHT 3 LEFT 4 now we can send a command SendCommand Command LEFT SendCommand Command STOP With this new approach there is no need to remember what commands exist and are the command numbers Once the word Command is typed in Visual Studio will give you a list of available commands C is also smart enough to increment the numbers for enumerations so the code can be like this listing and will work exactly the same way enum Command MOVE 1 STOP RIGHT LEFT Copyright 2010 GHI Electronics LLC Page 51 170 Beginners guide to C and NET Micro Framework C Level 2 now we can send a command
109. l kind of digital signals on any of the digital IOs For example OutputCompare can be used to generate a UART signal Or generate a signal to control a 38Khz infrared transmitter to simulate a TV remote control One very good example is the driver of 2x16 character serial display found on www TinyCLR com The display is controlled by UART Also the display doesn t send any data back All you need is to send some simple control commands serially to the display Now we can just connect the display to one of the available serial ports But then we will lose the port over something so simple plus the UART serial interface uses 2 pins for transmit and for receive But the display doesn t send any data back so basically you will lose the receive pin The right way to control this serial display is by using OutputCompare You will only need one pin and you can use any of the digital pins So how does OutputCompare work Basically you provide the method with an array of time values between each pin toggle The OutputCompare then goes through the array of time values and generate the signal on the requested pin So if are going to generate UART we first need to pre calculate the values needed to represent the transmitted byte and then provide that to the OutputCompare object The example driver should explain how this is done This is a copy of the driver found on www TinyCLR com for the serial LCD driver using System using System Threading u
110. le the garbage collector had to run only twice and it took only 448 milliseconds about half a second to run We only moved one line of code and it is 4 times faster Let us move the buffer globally and see using System Threading using System using Microsoft SPOT Hardware using Microsoft SPOT namespace MFConsoleApplication1 public class Program static SPI _spi new SPI new SPI Configuration Cpu Pin GPIO NONE false 0 0 false true 1000 SPI SPI module SPI1 static byte buffer new byte 2 static void WriteRegister byte register num byte value buffer register num buffer 1 value _spi Write buffer _spi Dispose public static void Main long ms long ticks DateTime Now Ticks for int i 0 i lt 1000 i WriteRegister 5 100 ticks DateTime Now Ticks ticks ms ticks TimeSpan TicksPerMillisecond Debug Print Time ms ToString Copyright 2010 GHI Electronics LLC Page 166 170 Beginners guide to C and NET Micro Framework Thinking Smallg We now have 368 milliseconds and garbage collector didn t run at all One quick check you can do on your device is to check the output to see how often does the garbage collector run On systems with large memory like ChipworkX this will not help much SO you still need to analyze the code manually Copyright O 2010 GHI Electronics LLC Page 167 170 Beginners guide to C and NET Micro
111. le from the file system but then the application becomes dependent on the file system to run Resources can also be strings like a copyright text This way we need to update the copyright text we would only need to update the resources and do nothing in the program code Always know how much memory is reserved for the application space Adding large file will result deploying errors and VS2010 will not tell you it is because the files are too large Looking in the Solution Explorer window we see the Resource resx and if we expand it we see Resources Designer cs og Solution MFConsoleApplication 1 project S 9 MFConsoleApplication H a Properties 3j References Program cs 5 Ea Resources resx 3 Resources Designer cs Visual Studio automatically generate the resources designer file Never try to modify this file manually Instead double click Resources resx to edit the resources using a tool p Resources resx Program cs MFConsoleApplication X lab Strings Ty Add Resource 7X Remove Resource E Name Value Comment gt Hello World Copyright O 2010 GHI Electronics LLC Page 90 170 Beginners guide to C and NET Micro Framework Loading Resources On the resource editor window the first drop down list on the left is to select what type of resources we want to edit You notice how there is already one string resource named String 1 With its value set t
112. lication can t afford that If so the garbage collector can be forced to run ata desired anytime force the garbage collector Debug GC true Copyright 2010 GHI Electronics LLC Page 64 170 Beginners guide to C and NET Micro Framework Garbage Collectog 15 1 Losing Resources The garbage collector ease object allocation but it can also cause problems if we are not careful A good example will be on using digital output pins Lets say we need a pin to be high We create an OuputPort object and set the pin high Later on we lose the reference for that object for some reason The pin will still be high when the reference is lost so all is good so far After few minutes the garbage collector kicks in and it finds this unreferenced object so it will be removed Freeing an OutputPort will case the pin to change its state to input Now the pin is not high anymore Turn the LED on OutputPort LED new OutputPort Cpu Pin FEZ Pin Digital LED true LED null we have lost the reference but the LED is still lit force the garbage collector Debug GC true The LED is now off An important thing to note is that if we make a reference for an object inside a method and the method returns then we have already lost the reference Here is an example using System using Microsoft SPOT using Microsoft SPOT Hardware namespace Test public class Program static void TurnLEDOn Turn the L
113. ms My suggestion is to start an RSA session to exchange XTEA key and some security info and then switch to XTEA Copyright O 2010 GHI Electronics LLC Page 127 170 Beginners guide to C and NET Micro Framework XML 26 XML 26 1 XML in Theory Extensible Markup Language XML is a standard for containing electronic data When you want to transfer some info between two devices you can set some rules on how the data is to be packed and sent from device A On the other side device B receives the data and knows how to unpack it This created some difficulties in the past before XML What if you were sending the data to a system implemented by different designer You will have to explain the other designer how you have packed your data so he she can unpack it Now designers can select to use XML to pack and unpack the data XML is extensively used daily in many ways For example when a website s shopping cart wants to know how much will be the shipping cost on a certain package you will need to pack your shipment details in XML format and then send to FedEx for example Then FedEx website will read the info and send the cost info back in XML format as well The usefulness of XML can also be utilized in other ways Let s say you are designing a data logger Let s also assume the end users will need to configure the data logger to fit their needs When a user configures the device you need to store the info internally somehow You can s
114. n conf new SPI Configuration Cpu Pin 33 false 0 0 false true 1000 SPI SPI module SPI2 SPI SPI port new SPI conf OutputPort RST new OutputPort Cpu Pin 9 true static OutputPort DC new OutputPort Cpu Pin 15 true static byte _ba new byte 1 static void OPTREX_SSD_WriteCmdByte byte b DC Write false Thread Sleep 1 ba 0 b SPI port Write ba static void OPTREX SSD WriteByte byte b DC Write true Thread Sleep 1 ba 0 b SPI port Write ba static void OPTREX_Locate int x int y if y gt 7 y 7 if x gt 127 x 127 OPTREX SSD WriteCmdByte byte 0X10 x gt gt 4 col up OPTREX SSD WriteCmdByte byte 0X00 x amp 0OxF col down OPTREX SSD WriteCmdByte byte 0XBO y page addr public static void Main OPTREX SSD WriteCmdByte 0XA2 bias OPTREX SSD WriteCmdByte 0XA1 adc inverse OPTREX SSD WriteCmdByte 0Xc0 common dir normal OPTREX SSD WriteCmdByte 0X40 initial line OPTREX SSD WriteCmdByte 0X81 evr set Copyright O 2010 GHI Electronics LLC Page 100 170 Beginners guide to C and NET Micro Framework Displays OPTREX SSD WriteCmdByte 0X20 OPTREX SSD WriteCmdByte 0X29 2B we have 10V wait for stable voltage Thread Sleep 10 OPTREX SSD WriteCmdByte 0XA4 turn all on OPTREX SSD WriteCmdByte 0XE7 driver OPTREX SSD WriteCmdByte 0XAF lcd on OPTREX SSD WriteCmdByte 0XA7 inverse OPT
115. n the card It is probably saved somewhere in the internal buffers To make sure the data is stored on the media we need to flush the data Flushing or closing a file is the only way to guarantee that the data you are trying to write are now on the actual media That is on file level On media level there are also information that may not take immediate effect For example if you delete a file and remove the card from the system the file is probably not actually erased To guarantee the file is erased media is updated you need to run Volumelnfo FlushALL Ideally you would unmounted the media before it is removed from the system This may not be always possible and so a flush on a file or a FlushAll on media will guarantee your data is saved so there is no lost data if the media was removed at some point Copyright O 2010 GHI Electronics LLC Page 118 170 Beginners guide to C and NET Micro Framework Networkingg 24 Networking Networks are an essential part of our work and living Almost every home is connected to a network internet and most businesses can t function without an internal network LAN or WiFi that is connected to an external network internet All these networks have a standard way for communication they all use TCP IP protocol There are actually a few protocols that handle different tasks in the network DNS DHCP IP ICMP TCP UDP PPP and many more NETMF supports TCP IP networks through standard NET
116. nfo in this book This book makes no assumption about what you the reader knows so everything is explained extensively have used my personal free time if that is ever available to make this book Expect a lot of typos and grammar errors but please report them on the forum so can enhance this book 2 2 Translating the Book This a book given to the community in an efforts to make NETMF easier for all users If you think you can translate the book to other languages then we would love see your contribution The original sources of this book and rules are on this page http www microframeworkprojects com index php titlezFree eBook Copyright O 2010 GHI Electronics LLC Page 5 170 Beginners guide to C and NET Micro Framework Introductiong 3 Introduction Have you ever thought of some great idea for a product but you couldn t bring it to life because technology wasn t on your side Or maybe thought there s got to be an easier way Maybe you are a programmer that wanted to make a security system but then thought using PCs are too expensive to run a simple system The answer is Microsoft s NET Micro Framework Here is a scenario you want to make a pocket GPS data logger that saves positions acceleration and temperatures on a memory card and displays them on a small display GPS devices can send position data over a serial port so you can easily write some code on a PC to read the GPS data and save it on a file But a PC
117. ng This is actually supported by NETMF and GHI adds much functionality making it very easy to setup Important note You can t use the USB client port for both debugging and something else Once you decide you want to use the USB client port for your own use then you no longer can use the USB port for debugging By the way GHI did support debugging and customizing the USB interface simultaneously through using multiple interfaces on the same USB interface but this caused a huge load of support due to improper use and so simultaneous use support was dropped Let me give you an example on the USB client usage Let us say you are making a device that that reads temperature and humidity etc and logs all this data on an SD card Also this device can be configured like to set the time or give file names etc You want the device to be configured over USB So when your device plugs into a USB port you want it to show as a virtual serial port This way anyone can open a terminal software like TeraTerm to connect to your device to configure it This is where USB client becomes very useful There is no need to add extra cost to the design but adding additional RS232 serial ports or USB lt gt serial chipsets The built in USB client port can be configured to act as a CDC device virtual COM port But there is a catch The catch is you still need to connect the PC to your device serially for debugging and deploying applications since the USB cli
118. nternal buffers in native code to keep the data ready until the developer uses the data from managed code If we need a 1 megabyte file we do not need a large buffer at all We create a small buffer and then send the data in chunks to the file system To play a 5 megabyte MP3 file we only need 100 byte buffer that will read chunks from the file and pass to the MP3 decoder 33 2 Object Allocation Allocating and freeing objects is very costly Only allocate objects when you really needs them Also you are making an embedded device therefore a lot of objects that you will be using are always used For example you will always use the LCD or always use the SPI Consider the following code using System Threading using System using Microsoft SPOT Hardware using Microsoft SPOT namespace MFConsoleApplication1 public class Program Copyright O 2010 GHI Electronics LLC Page 163 170 Beginners guide to C and NET Micro Framework Thinking Small static void WriteRegister byte register_num byte value SPI _spi new SPI new SPI Configuration Cpu Pin GPIO NONE false 0 0 false true 1000 SPI SPI module SPI1 byte buffer new byte 2 buffer 0 register num buffer 1 value _spi Write buffer public static void Main WriteRegister 5 100 In order for me to write a single byte to a register on a SPl chip had allocated SPI object SPI Configuration object and a b
119. o Hello World Click right below String 1 and add a new string resource as shown in image below _ Resources resx Program cs MFConsoleApplication 2 abe Strings Add Resource 7X Remove Resource Name 4 Value Comment Stringl Hello World String2 This is great We now have two string resources Let us use them using System Threading using Microsoft SPOT using System namespace MFConsoleApplication1 public class Program public static void Main Debug Print Resources GetString Resources StringResources String1 Debug Print Resources GetString Resources StringResources String2 Try modifying the string resource text and observe how the output changes Let us add a file Create a text file on your desktop and put some text in it Select files from the left drop down menu then clock on Add Resource Copyright 2010 GHI Electronics LLC Page 91 170 Beginners guide to C and NET Micro Framework Loading Resources Start Page Resources resx Prog 4 Files Add Resource X Since this is a text file Visual Studio is smart enough to add this in a similar way to strings So to use this resource file we access it the same way we access a string using System Threading using Microsoft SPOT using System namespace MFConsoleApplication1 public class Program public static void Main
120. o C and NET Micro Framework Expanding VOsg using System Threading using System using Microsoft SPOT Hardware using Microsoft SPOT namespace MFConsoleApplication1 public class Program static OutputPort Rows new OutputPort 3 static InputPort Colms new InputPort 3 static bool ReadMatrix int row int column bool col state select a row Rows row Write true read the column col state Colms column Read deselectt the row Rows row Write false return col state static void Main 1 initialize rows to outputs and low Rows new OutputPort Cpu Pin 1 false Rows 1 new OutputPort Cpu Pin 2 false Rows 2 new OutputPort Cpu Pin 3 false initialize inputs with pull down Colms new InputPort Cpu Pin 4 true Port ResistorMode PullDown Colms 1 new InputPort Cpu Pin 5 true Port ResistorMode PullDown Colms 2 new InputPort Cpu Pin 6 true Port ResistorMode PullDown while true bool state read the button on the first row and first column state ReadMatrix 0 0 we count from zero Debug Print Buton state is state ToString read the button on the third row and second column state ReadMatrix 2 1 we count from zero Debug Print Buton state is state ToString Copyright 2010 GHI Electronics LLC Page 135 170 Beginners guide to C and NET Micro Framework Expanding VOsg
121. oad a new program Basically lock out the device You need to enter the boot loader to erase all to unlock the device from its hibernation Important Note When you hibernate the system clock stops not RTC so the NETMF time will be off You will need to read the time from RTC and set the NETMF sytsem time after waking up from hibernation Waking up from hibernate is only possible on few events Check your device user manual or the library documentation for details An easy way to wake up from hibernate is by using the alarm feature when available For example FEZ Rhino includes the 32Khz clock needed for the built in RTC alarm but FEZ Mini doesn t See this link for more details http www tinyclr com compare Copyright 2010 GHI Electronics LLC Page 146 170 Beginners guide to C and NET Micro Framework Low Powery In this example set the RTC to some random but valid time and then blink an LED Every three seconds the device sets the alarm to wake up in 10 seconds and then it put the device into hibernation The device will be completely dead again no USB debugging but you should be able to see this on the LED When the device wakes up it continue on blinking the LED At the end the LED will blink for 3 seconds and then stops for 10 seconds using System using System Threading using Microsoft SPOT using GHIElectronics NETMF Hardware using GHIElectronics NETMF Hardware LowLevel using GHIElectronics NETM
122. on component Copyright O 2010 GHI Electronics LLC Page 155 170 Beginners guide to C and NET Micro Framework Wireless 31 2 Bluetooth Almost every cellphone has everything needed to connect to Bluetooth devices Bluetooth technology defines multiple profiles for connections The audio profile is useful to connect the Bluetooth ear piece to the phone For data transfers SPP Serial Port Profile is used to establish a connection that simulates a serial connection This is very similar to how XBee modules connect Most phones have Bluetooth but most do not implement SPP so creating a serial connection from your phone is probably not possible On windows we can create a serial Bluetooth connection with few clicks 1 Find Bluetooth Devices in Control Panel Click on Bluetooth Settings View the COM ports tab If you have COM ports installed then you already have SPP enables on your PC J e ge To add new ports click on Add 6 Create one port for incoming data and one for outgoing Windows creates two ports one for incoming and one for outgoing data This can be confusing to Windows users because they can t use the same port to send and receive data Copyright 2010 GHI Electronics LLC Page 156 170 Beginners guide to C and NET Micro Framework Wireless 8 Bluetooth Radio Properties PIM Interface Audio Dial up COM Ports Hardware Shae This computer is using the COM serial por
123. op start and end with curly brackets to contain some code Everything inside will continuously run while a statement is true For example can ask you to keep reading this book while you are awake So let s make the program that continuously print Amazing endlessly This endless loop has no ending so it will always be true using System using Microsoft SPOT namespace MFConsoleApplication1 public class Program public static void Main while true Debug Print Amazing Copyright 2010 GHI Electronics LLC Page 24 170 Beginners guide to C and NET Micro Framework C Level J In the code above execution will start at Main method as usual and then it will go to the next line which is the while loop The while loop is telling the run time to execute the code inside its brackets while the statement is true Actually we do not have a statement there but we have true instead which means this loop will always run Do not hit F5 to run the program or you will flood the output window with the word Amazing Instead hit F11 and step in the code to understand how the loop works Note that this program will never end so you will need to force stop using shift F5 Note You can reach all these debug shortcuts from the menu under Debug Variables Variables are places in memory reserved for your use The amount of memory reserved for you depends on the type of the va
124. option is to install an event handler for the button like the following using System using System Threading using Microsoft SPOT using Microsoft SPOT Hardware using GHIElectronics NETMF Hardware using GHIElectronics NETMF Hardware LowLevel using GHIElectronics NETMF FEZ public class Program public static void Main blink LED FEZ_Components LED led new FEZ_Components LED FEZ_Pin Digital LED led StartBlinking 100 100 setup the interrupt pin InterruptPort LDR new InterruptPort Cpu Pin O false Port ResistorMode PullUp Port InterruptMode InterruptEdgeLow LDR OnInterrupt new NativeEventHandler LDR OnInterrupt while true Thread Sleep 3000 blink LED for 3 seconds sleep Power Hibernate Power WakeUpInterrupt InterruptInputs we get here when we wakeup static void LDR OnInterrupt uint datal uint data2 DateTime time empty for now Please note that using InputPort is as good as using the InterruptPort since internally the interrupts are used when glitch filter is enabled Here is the example using InputPort instead of InterruptPort using System using System Threading Copyright O 2010 GHI Electronics LLC Page 149 170 Beginners guide to C and NET Micro Framework Low Powery using Microsoft SPOT using Microsoft SPOT Hardware using GHIElectronics NETMF Hardware using GHIElectronics NETMF Hardware LowLevel usin
125. ore and after the word Amazing That is because C doesn t know if the text you are writing is actually command or it is actually text strings You can see how it is colored in red when you add quotes which makes reading code easier for us humans Comments What if you want to add comments notes warnings in your code Those comments will help you and others understand what the code means C completely ignores these comments There are 2 ways to create comments line comments and block comments Comments Ignored text are shown in green To comment a line or part of a line add before the comment text The color of the text will change to green indicating that the text is now comment and is ignored by C using System using Microsoft SPOT namespace MFConsoleApplication1 public class Program public static void Main This is a comment Debug Print Amazing this is a comment too Copyright 2010 GHI Electronics LLC Page 23 170 Beginners guide to C and NET Micro Framework C Level J You can also comment a whole block Start the comment with and then end it with symbols using System using Microsoft SPOT namespace MFConsoleApplication1 public class Program public static void Main This is a comment it it still a comment the block will end now Debug Print Amazing while loop It is time for our first keyword while The while lo
126. ore items out Here is a simple example Copyright O 2010 GHI Electronics LLC Page 153 170 Beginners guide to C and NET Micro Framework Watchdog JT aes Tb s Timeout 1 second uint timeout 1000 user buys something Enable Watchdog Watchdog Enable timeout turn motors on heii stop motors MELE We don t need Watchdog anymore we have to keep resetting the timeout Watchdog Enable Watchdog MAX TIMEOUT WDTCounterReset Start See this in the earlier example IL wes your program starts here JU asssvie IT paas Detecting Watchdog Cause In some cases you need to know if the system did reset because of a watchdog to log this info or run some recovery procedures This is how it works using System using System Threading using Microsoft SPOT using GHIElectronics NETMF Hardware LowLevel public class Program public static void Main you can read this flag ONLY ONCE on power up if Watchdog LastResetCause Watchdog ResetCause WatchdogReset Debug Print Watchdog did Reset else Debug Print Reset switch or system power Copyright 2010 GHI Electronics LLC Page 154 170 Beginners guide to C and NET Micro Framework Wireless 31 Wireless Wireless technologies are becoming an essential part of our life Some applications require high rate data transfer others require very low power Some require a point
127. orithms to support The algorithms are XTEA and RSA 25 1 XTEA XTEA with its 16byte 128bit key is considered to be very secure and at the same time it doesn t require a lot of processing power Originally XTEA was designed to work on chunks of eight bytes only This can be a problem if encrypting data that it size is not multiple of 8 The implementation of XTEA on NETMF allows for encrypting data of any size Encrypting and decrypting data is straight forward Here is an example using System using System Text using Microsoft SPOT using Microsoft SPOT Cryptography public class Program public static void Main 16 byte 128 bit key byte XTEA_key new byte 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Key_TinyEncryptionAlgorithm xtea new Key_TinyEncryptionAlgorithm XTEA_key The data we want to encrypt string original_string FEZ is so easy must be more than 8 bytes convert to byte array byte original_data UTF8Encoding UTF8 GetBytes original_string Encrypt the data byte encrypted bytes xtea Encrypt original data 0 original data Length null Decrypt the data byte decrypted bytes xtea Decrypt encrypted bytes 0 encrypted bytes Length null print the decrypted data string decrypted string new string Encoding UTF8 GetChars decrypted bytes Debug Print original string Copyright O 2010 GHI Electronics LLC Page 124 170 Beginner
128. ot work anymore Here is the error message showing after commented out using Microsoft SPOT using Microsoft SPOT namespace MFConsoleApplicationi 1 public class Program 1 public static void Main 1 Debug Print Amazing 4 n Error List A0 Warnings i 0 Messages Description File Line Q1 Thename Debug does not exist in the Program 10 current context We used the assemblies but where are they added Uncomment the code and make sure it still works Now take a look at Solution Explorer window Click the little sign by the word References and you should see two assemblies Copyright O 2010 GHI Electronics LLC Page 28 170 Beginners guide to C and NET Micro Framework C Level ly a Solution MFConsoleApplication 1 project H Sa Properties H aw Xia o o 03 Microsoft SPOT Native 3 mscorlib Program cs H Ga Resources resx Now right click on Microsoft SPOT Native then click Remove amp l MFConsoleApplication H a Properties Our program still be exactly the same as before but now it is missing a very important assembly Try to run it and you will see something like this using Microsoft SPOT EI MEM MFConsoleApplicationi El public class Program 1 El public static void Main 1 Error Lit i tt sts SS Q1 Error A0 Warnings i
129. ouple seconds everything will stop That is because our program had finished execution so fast that we didn t see much We want to debug the code now Debugging means that you are able to step in the code and see what it is doing This is one of the greatest values of NETMF This time use F11 instead of F5 this will step in the application instead of just running it This will deploy the application on the emulator and stop at the very first line of the code This is indicated by the yellow arrow namespace MFConsoleApplicationi 1 E public class Program public static void M e t Debug Print Ama ud Sample Emulator Insert Eject C applications always start from a method called Main and this is where the arrow had stopped Press F11 again and the debugger will run the next line of code which is the line you changed before You probably have guessed it right this line will print Amazing to the debug window The debug window is the output window on Visual C Express Make sure Output window is visible like explained earlier and press F11 one more time Once you step on that line you will see the word Amazing showing in the output window Copyright O 2010 GHI Electronics LLC Page 17 170 Beginners guide to C and NET Micro Framework Getting Started public static void Main Debug Print Amazing gt b Output 23x Show output from
130. ource files coming with NETMF SDK examples The samples at Documents Microsoft NET Micro Framework 3 0 Samples used NinaB tinyfnt font file Add the file to your resources like explained in previous chapter We can now run this code to print on the LCD using System Threading using Microsoft SPOT using System using Microsoft SPOT Presentation using Microsoft SPOT Presentation Media namespace MFConsoleApplication1 public class Program public static void Main Bitmap LCD new Bitmap SystemMetrics ScreenWidth SystemMetrics ScreenHeight Font MyFont Resources GetFont Resources FontResources NinaB clears the memory and not the display LCD Clear int i for i 10 i lt 200 i 4 draw on memory LCD DrawLine Colors Green 1 10 i i 200 print some text on the screen LCD DrawText Still Amazing MyFont Colors Red 100 20 transfer the bitmap memory to teh actual display Copyright 2010 GHI Electronics LLC Page 97 170 Beginners guide to C and NET Micro Framework Displays LCD Flush Copyright 2010 GHI Electronics LLC Page 98 170 Beginners guide to C and NET Micro Framework Displays Non native support Many small graphical displays use SPI bus to receive images from the host NETMF devices usually support large TFT displays that use a special bus to operate like FEZ Cobra EMX But even if the system doesn t sup
131. popular programming languages C is an updated and modern version of C and C It includes everything you would expect in a modern language like garbage collector and run time validation It is also object oriented which makes programs more portable and easier to debug and port Although C puts a lot of rules on programming to shrink down the bug possibilities it still offers most of the powerful features C C have Main is the Starting Point Like we seen before programs always start at a method called Main A method is a little chunk of code that does a certain task Methods start and finish with open close curly bracket In our first program we only had one line of code in between the curly brackets The line was Debug Print Amazing You can see how the line ends with a semicolon All lines must end the same way Copyright O 2010 GHI Electronics LLC Page 22 170 Beginners guide to C and NET Micro Framework C Level J This line calls the Print method that exists in the Debug object It calls it while passing the string Amazing Confused Let s try to clear it out a bit Let s say you are an object You also have multiple methods to control you the object One method can be Sit and another can be Run Now what if want you to Say amazing will be calling your speak method with the sentence string Amazing So the code will look like You Say Amazing Now why do we need the quotes bef
132. port those displays like FEZ Rhino USBizi user can connect an SPl based display and display graphics this way It is also possible to have two displays on system that support native TFT interface A large display will run on the TFT interface and the smaller display will run on a SPI bus Even tough SPI is very fast displays can have millions of pixels so we need to take this under consideration when selecting a display Www TinyCLR com offers many displays SPI or TFT that are ideal to work with GHI offers Below is one of the example Also check the standard SPl based display for FEZ Rhino on the website mentioned earlier Native support on non standard display A better option is to use the bitmap class to draw text draw shapes and then transfer the bitmap to your display You can only use this if Bitmap graphics is supported on your device USBizi doesn t support graphics This code will display some data on the F 51852 128x64 pixel display found on the old non TFT Embedded Master development system using System using System Text using System Threading using Microsoft SPOT using Microsoft SPOT Presentation using Microsoft SPOT Presentation Media Copyright O 2010 GHI Electronics LLC Page 99 170 Beginners guide to C and NET Micro Framework Displays static static static using Microsoft SPOT Hardware using GHIElectronics NETMF System public class Program SPI Configuratio
133. provided by GHI for convenience to its customers and to optimize the W5100 driver to work more efficiently Until GHI driver is available anyone with some experience can implement a W5100 driver to fit their needs Copyright O 2010 GHI Electronics LLC Page 119 170 Beginners guide to C and NET Micro Framework Networkingg 24 2 Raw TCP IP vs Sockets This is an area when most designers miss few important points When selecting a WiFi or GPRS 3G module there are two main module categories to select from Modules with sockets and modules with raw TCP IP The modules with sockets handle all TCP IP work internally and give you a high level socket access This means that all the work is being done already inside the module Once you set your IP and port number all you have to do is send and receive data from the module The catch is this is very limited The module will have many limitations like socket count Even if your system is very powerful with megabytes of RAM you still is limited by the module s features For this reason using these high level modules is ideal for small systems Let me give you an example Roving Networks provides a module called WiFly This module has a built in TCP IP stack and only one socket support Using the module is very easy as you only need to connect it to one of the serial ports on your system then with simple serial commands you can read write data from the one available socket This is enough to ma
134. r will free objects at some point but if we need to free one particular object immediately Most objects have a Dispose method If an object needs to be freed at anytime we can dispose it Disposing object is very important in NETMF When we create a new InputPort object the assigned pin is reserved What if we want to use the same pin as an output Or even use the same pin as an analog input We will first need to free the pin and then create the new object Copyright O 2010 GHI Electronics LLC Page 66 170 Beginners guide to C and NET Micro Framework Garbage Collectog OutputPort OutPin new OutputPort Cpu Pin FEZ Pin Digital Di5 true OutPin Dispose InputPort InPort new InputPort Cpu Pin FEZ Pin Digital Di5 true Port ResistorMode PullUp 15 3 GC Output Messages When the garbage collector runs it outputs a lot of useful information to the output window These messages give you an idea of what is using resources in the system Although not recommended you may want to disable those messages to free up the output window for your own usage This is easily achievable using this line of code Debug EnableGCMessages false Copyright O 2010 GHI Electronics LLC Page 67 170 Beginners guide to C and NET Micro Framework Cx Level 3J 16 C Level 3 This section will cover all C materials we wanted to include in this book A good and free eBook to continue learning about C is availa
135. rence must be lost This is all you need for regular objects The garbage collector must run you probably need to force it The system must come idle in order for finalize to run and Dispose object Copyright O 2010 GHI Electronics LLC Page 159 170 Beginners guide to C and NET Micro Framework Objects in Custom Heapg will not go into detail on garbage collectors dispose or finalizer etc What you need to know is that large object that are on custom heap are not easily cleared from the system so you must always dispose the object when you are done using it This is how you can dispose large objects using System using Microsoft SPOT Hardware using GHIElectronics NETMF Hardware class Program public static void Main allocate a 1MB buffer LargeBuffer lb new LargeBuffer 1024 1024 use the buffer lb Bytes 5 123 14 wies when done dispose the object to empty the memory lb Dispose The better option is to use the using statement This statement will automatically call dispose once the execution is leaving the using curly brackets using System using Microsoft SPOT Hardware using GHIElectronics NETMF Hardware class Program public static void Main allocate a 1MB buffer using LargeBuffer lb new LargeBuffer 1024 1024 use the buffer lb Bytes 5 123 I ass Dispose was called automatically PE xu Copyri
136. riable will not cover every single type here but any C book will explain this in details We will be using int variable This type of variable is used to hold integer numbers Simply saying int MyVar will tell the system that you want some memory to be reserved for you This memory will be referenced to as MyVar You can give it any name you like as long as the name doesn t contain spaces Now you can put any integer number in this memory MyVar 1234 You can also use mathematical operations to calculate numbers MyVar 123 456 or you can increment the number by one MyVar or decrement it by one MyVar With all that can we make a program that prints the word Amazing three times Here is the code using System using Microsoft SPOT namespace MFConsoleApplication1 Copyright 2010 GHI Electronics LLC Page 25 170 Beginners guide to C and NET Micro Framework C Level J public class Program public static void Main int MyVar MyVar 3 while MyVar gt MyVar Debug Print Amazing Note how the while loop statement is not always true anymore but it is MyVar gt 0 This is saying keep looping as long as MyVar value is more than 0 In the very first loop MyVar is 3 Inside every loop we decrement MyVar by one This will result in the loop running exactly three times and therefore printing Amazing three times Let s make things more int
137. right O 2010 GHI Electronics LLC Page 75 170 Beginners guide to C and NET Micro Framework Serial Interfacesg 17 Serial Interfaces There are many serial interfaces available for data transfer between processors Each interface has its advantages and disadvantages will try to cover them in enough details so you can use them with NETMF Even though there are many serial interfaces when we say we talk about serial we mean UART or RS232 Other interfaces like CAN and SPI still transmit its data serially but they are not serial ports If further details are needed consult the web especially http www wikipedia org 17 1 UART UART is one of the oldest and most common interfaces Data is sent out on a UART TXD pin in a sequence at a predefined speed When the transmitter sends out zeros and ones the receiver is checking for incoming data on RXD at the same speed that the transmitter is sending The data is sent one byte at the time This is one direction for data To transfer the data in the opposite direction a similar circuit is constructed at the opposite side Transmit and receive are completely separate circuits and they can work together or independently Each side can send data at any time and can also receive data at anytime The predefined speed of sending receiving data is called baud rate Baud rate is how many bits are transmitted in one second Usually one of the standard baud rates are used like 9600 119200 115
138. ring AnalogIn BatteryVoltage new AnalogIn AnalogIn Pin FEZ Pin AnalogIn An0O BatteryVoltage SetLinearScale 3300 int voltage BatteryVoltage Read Debug Print Voltage voltage 1000 ToString voltage X 1000 ToString Copyright O 2010 GHI Electronics LLC Page 61 170 Beginners guide to C and NET Micro Framework Analog input amp output We divide by 1000 to get the voltage and then we use the modules to get the fraction 14 2 Analog Outputs Analog outputs are like digital outputs where they have limits on how much power they can provide Analog outputs are even weaker than digital outputs They are only capable of providing a very little signal to drive the power circuit maybe drive a power amplifier Digital outputs can only be high or low but analog input can be set to any voltage between 0 and 3 3V GHI implementation for analog outputs allows for automated scaling You can give it a min max and the actual value An easy test would be to set the min to zero and max to 330V 3 3Vx100 then the value to 100 1Vx100 This will give us 1V on the pin We will connect this pin to another analog input to measure the value to verify it is 1V It may not be exactly 1V but will be very close The analog output is multiplexed with analog input 3 When using the analog output the analog input can be used on this pin but we can use any other analog input on other pins using System
139. rint Storage e Volume RootDirectory is inserted Debug Print Getting files and folders if e Volume IsFormatted string files Directory GetFiles e Volume RootDirectory string folders Directory GetDirectories e Volume RootDirectory Debug Print Files available on e Volume RootDirectory for int i 0 i files Length i Debug Print files i Debug Print Folders available on e Volume RootDirectory for int i 0 i folders Length i Debug Print folders i else Debug Print Storage is not formatted Format on PC with FAT32 FAT16 first Copyright 2010 GHI Electronics LLC Page 117 170 Beginners guide to C and NET Micro Framework File System static void RemovableMedia Eject object sender MediaEventArgs e Debug Print Storage e Volume RootDirectory is ejected You can see from the code above how after we mount the USB drive to the file system everything work exactly the same as SD cards 23 3 File System Considerations NETMF support for FAT File System is only capable of FAT32 and FAT16 A media formatted as FAT12 will not work This shouldn t be an issue since FAT 12 is no longer in use The file system does a lot of data buffering internally to speed up the file access time and to increase the life of the flash media When you write data to a file it is not necessary that the data is written o
140. rs need therefore GHI implemented its own version of watchdog Do not use the watchdog from Microsoft SPOT Hardware instead use the watchdog from GHIElectronics NETMF Hardware LowL evel If both namespaces must be used then you will have ambiguity errors and so you need to specifically call out the full path of the watchdog you need For example instead of using Watchdog Enable timeout use GHIElectronics NETMF Hardware LowLevel Watchdog Enable timeout This example shows how to set the watchdog to 5 seconds timeout and create a thread to clear the watchdog every 3 seconds Should anything go wrong the device will reset in 5 seconds Important Note Once you enable the Watchdog it cannot be disabled So you have to keep resetting the timeout This is done to assure that no system corruption will disable watchdog accidentally using System using System Threading using GHIElectronics NETMF Hardware LowLevel public class Program public static void Main Timeout 5 seconds uint timeout 1000 5 Enable Watchdog Watchdog Enable timeout Copyright 2010 GHI Electronics LLC Page 152 170 Beginners guide to C and NET Micro Framework Watchdog Start a time counter reset thread WDTCounterReset new Thread WDTCounterResetLoop WDTCounterReset Start JU sess your program starts here If we exit the program the thread will stop working and the system will reset
141. ry second using System Threading using Microsoft SPOT using System namespace MFConsoleApplication1 public class Program Copyright 2010 GHI Electronics LLC Page 104 170 Beginners guide to C and NET Micro Framework Time Services static void RunMe object o Debug Print From timer public static void Main Timer MyTimer new Timer new TimerCallback RunMe null 5000 1000 Debug Print The timer will fire in 5 seconds and then fire priodically every 1 second Thread Sleep Timeout Infinite Copyright 2010 GHI Electronics LLC Page 105 170 Beginners guide to C and NET Micro Framework USB Host 22 USB Host There is almost always confusion between USB host and USB device The USB host is the system that connects to multiple USB devices For example the PC is a USB host and it can connect to multiple USB devices like mice keyboards and mass storage devices Implementing a USB device is rather simple but implementing a host is far more complicated USB host is an exclusive feature from GHI Electronics With this exclusive feature you can connect almost any USB device to GHI s NETMF products USBizi Embedded Master ChipworkX This feature opens new possibilities for embedded systems Your product can now connect to a standard USB keyboard and can also access files on a USB thumb drive USB is a hot pluggable system which means any device can be
142. s Copyright O 2010 GHI Electronics LLC Page 13 170 Beginners guide to C and NET Micro Framework Getting Startedy 6 Getting Started Important note If you have just received your hardware or you are not sure what firmware is loaded on it you MUST update the firmware The documentation manual or tutorial of your device shows you how to update the firmware This is a required step Also make sure you read the firmware assembly matching section in this book 6 1 System Setup Before we try anything we want to make sure the PC is setup with needed software First download and install Visual C express 2010 VS2008 or older will not work http www microsoft com express vcsharp Now download and install NET Micro Framework 4 1 SDK not the porting kit http www microsoft com downloads details aspx displaylang en amp FamilyID cffba7b7 c21c 4127 ac65 5516384da3a0 If link above didn t work search for NET Micro Framework 4 1 SDK Finally install the GHI NETMF SDK You can get the SDK from http www tinyclr com dl 6 2 The Emulator NETMEF includes an emulator that allows the running of NETMF applications right on the PC For our first project we will use the emulator to run a very simple application Create a Project Open Visual C Express and from the menu select file gt New Project The wizard now should have Micro Framework option in the left menu Click on it and from the templat
143. s for example If you need a real network connection with full blown TCP IP stack then you need EMX or ChipworkX with a standard PPP modems just like how would your PC connect to the internet using a standard modem If you need a simple and low cost connection then USBizi FEZ can be used with SM5100B The SparkFun Cellular Shield showing on the right plugs right into FEZ Domino 24 3 Standard NET Sockets The socket supported on NETMF is very similar to the full NET Framework The NETMF SDK includes many examples for using sockets client and server Also many projects are available showing the different possibilities Twitter client http www microframeworkprojects com index php title2 MF Twitter Google maps http www microframeworkprojects com index php title GoogleMaps RSS client http www microframeworkprojects com index php title RSS_n_Weather MP3 internet radio http www microframeworkprojects com index php title ShoutcastClient Web server http www microframeworkprojects com index php title WebServer Copyright 2010 GHI Electronics LLC Page 121 170 Beginners guide to C and NET Micro Framework Networkingg 24 4 Wi Fi 802 11 WiFi is the most common way for computer networking It allows secure data transfers at high rates to multiple connections WiFi allows connections between two nodes called Ad Hoc The more common way is to connect multiple computers to an access point WiFi is not simple an
144. s guide to C and NET Micro Framework Cryptographyg Debug Print decrypted string The encrypted data has the same size as the unencrypted data XTEA on PCs Now you can share data between NETMF devices securely using XTEA but what about sharing data with a PC or other systems The book Expert NET Micro Framework Second Edition by Jens Kuhner includes source examples showing how to implement XTEA on a PC Using Jen s code you can encrypt data then send to any NETMF device or vice versa Even if you do not own the book the source code is online found in chapter 8 Download the source code from here http apress com book view 978 1590599730 25 2 RSA XTEA is very secure but has an important limitation a key must be shared For example in order for any two systems to share encrypted data they first both must share the same key If a system tried to send the key to the other system then anyone spying on the data can get the key and use it to decrypt the data Not very secure anymore RSA overcomes this problem by providing a private and public key combination This may not make sense but the key used for encryption can t be used to decrypt the data A different key is needed to decrypt the data Lets say system A needs to read some secure data from system B The first thing system A will do is send a public key to system B System B will now encrypt the data using the public key and send the encrypted data to th
145. s like microwave ovens have many buttons on the front A user will never need to press two buttons at the same time so we can matrix those buttons If we have 12 buttons on our system then we will need 12 digital inputs from the processor to read them all Connecting these buttons in a 4x3 matrix will still give us 12 buttons but we are only using seven pins from the processor instead of 12 There are many off the shelf button matrix that can be integrated in your product To connect buttons in a matrix we will wire our circuit so there are rows and columns Each button will connect to one row and one column That is all for hardware Note how if we are not using a matrix then the button will connect to an input pin and ground To read the buttons state make all processor pins connecting to rows outputs and the ones connecting to columns inputs Set one and only one of the rows high and the rest of all rows to low We are now selecting what row of buttons we will read Now read the state of all buttons in that row you are reading the columns now When complete set the one row back to low and then go to the next one and set it high then go back to read the columns Keep repeating until every row have been set to high once This example assumes we have a matrix with these connections three rows connected to pins 1 2 3 and three columns connected to pins 4 5 6 Copyright O 2010 GHI Electronics LLC Page 134 170 Beginners guide t
146. sensors or EEPROMs use only a single wire for data transfers Multiple devices can be connected and controlled on a single wire The one wire class provide many methods to read and write bytes from one wire devices It also includes the one wire CRC calculation method as well This example will read the temperature from DS18B20 one wire digital thermometer Note that this is a GHI exclusive feature and so it requires adding the GHI assembly to the build using System using System Threading using Microsoft SPOT using Microsoft SPOT Hardware using GHIElectronics NETMF Hardware using GHIElectronics NETMF FEZ namespace Test i public class Program public static void Main i Change this your correct pin Cpu Pin myPin Cpu Pin FEZ_Pin Digital Di4 OneWire ow new OneWire myPin ushort temperature read every second while true if ow Reset ow WriteByte xCC Skip ROM Copyright 2010 GHI Electronics LLC Page 83 170 Beginners guide to C and NET Micro Framework Serial Interfaces ow WriteByte 0x44 Start temperature conversion while ow ReadByte 0 wait while busy ow Reset ow WriteByte xCC skip ROM ow WriteByte xBE Read Scratchpad temperature ow ReadByte LSB temperature ushort ow ReadByte lt lt 8 MSB Debug Print Temperature temperature 16 Thread Sleep 10 else Debug Print Device is not det
147. sing Microsoft SPOT Hardware using GHIElectronics NETMF Hardware namespace GHIElectronics NETMF FEZ public static partial class FEZ Components public class SerialLCD IDisposable const byte DISP ON 60xC Turn visible LCD on const byte CLR DISP 0x01 Clear display const byte CUR HOME 2 Move cursor home and clear screen memory const byte SET CURSOR 0x80 SET CURSOR X Sets cursor position to X const byte Move CURSOR LEFT 0x10 OutputCompare oc const int MAX TIMINGS BUFFER SIZE 10 uint buffer new uint MAX TIMINGS BUFFER SIZE Copyright O 2010 GHI Electronics LLC Page 87 170 Beginners guide to C and NET Micro Framework Output Compare const int BAUD RATE 2400 const int BIT TIME US 1 1000 1000 BAUD RATE readonly int BYTE TIME MS public void Dispose oc Dispose buffer null private void SendByte byte b bool currentPinState int currentBufferIndex 0 uint currentStateTiming start bit currentPinState false currentStateTiming BIT TIME US data bits for int i i lt 8 i bool neededState b amp 1 lt lt i if neededState currentPinState currentStateTiming BIT_TIME_US currentPinState neededState currentBufferIndex else stop bit if currentPinState true currentStateTiming BIT_TIME_US currentBufferIndex wait till data is sent T
148. ss Program public static void Main OutputPort LED InputPort Button bool button state LED new OutputPort Cpu Pin FEZ Pin Digital LED true Button new InputPort Cpu Pin FEZ Pin Digital LDR false Port ResistorMode PullUp while true button_state Button Read if button_state true LED Write false else LED Write true Thread Sleep 10 will let you in on a secret We only used if statement and else statement in this example for Copyright O 2010 GHI Electronics LLC Page 45 170 Beginners guide to C and NET Micro Framework C Level 2 demonstration purposes only We can write the code this way using System using Microsoft SPOT using System Threading using Microsoft SPOT Hardware using GHIElectronics NETMF FEZ namespace MFConsoleApplication1 public class Program public static void Main OutputPort LED InputPort Button LED new OutputPort Cpu Pin FEZ_Pin Digital LED true Button new InputPort Cpu Pin FEZ_Pin Digital LDR false Port ResistorMode PullUp while true LED Write Button Read false Thread Sleep 10 Or even this way using System using Microsoft SPOT using System Threading using Microsoft SPOT Hardware using GHIElectronics NETMF FEZ namespace MFConsoleApplication1 public class Program public static void Main OutputPort LED InputPort Button LED new Outpu
149. ssingInstruction xml version 1 0 encoding utf 8 xmlwrite WriteComment This is just a comment xmlwrite WriteRaw r n xmlwrite WriteStartElement NETMF DataLogger root element xmlwrite WriteString r n t xmlwrite WriteStartElement FileName child element xmlwrite WriteString Data xmlwrite WriteEndElement xmlwrite WriteRaw r n t xmlwrite WriteStartElement FileExt xmlwrite WriteString txt xmlwrite WriteEndElement xmlwrite WriteRaw r n t xmlwrite WriteStartElement SampleFeq xmlwrite WriteString 10 xmlwrite WriteEndElement xmlwrite WriteRaw r n xmlwrite WriteEndElement end the root element xmlwrite Flush xmlwrite Close display the XML data byte byteArray ms ToArray char cc System Text UTF8Encoding UTF8 GetChars byteArray string str new string cc Copyright 2010 GHI Electronics LLC Page 131 170 Beginners guide to C and NET Micro Framework XML Debug Print str 26 3 Reading XML Creating XML files is actually easier than parsing reading them There are many ways to read the XML file but basically you can just go through the file and read one piece at the time till you reach the end This code example creates an XML data and it reads it back using System IO using System Xml using System Ext Xm1l using Microsoft SPOT public class Program public static void Ma
150. t 10000 50 i Copyright O 2010 GHI Electronics LLC Page 55 170 Beginners guide to C and NET Micro Framework Pulse Width Modulationg From the list above you can see that the LED is connected to a PWM signal Instead of blinking LED what about we fade it in and out This will make it look so much cooler Here is the code using System using Microsoft SPOT using System Threading using Microsoft SPOT Hardware using GHIElectronics NETMF Hardware using GHIElectronics NETMF FEZ namespace MFConsoleApplicationi public class Program public static void Main sbyte dirr 1 byte duty 40 PWM pwm new PWM PWM Pin FEZ Pin PWM LED while true pwm Set 10000 duty duty byte duty dirr if duty gt 90 duty lt 10 dirr 1 Thread Sleep 10 The code will loop while incrementing the energy of the LED to 9096 and then goes back and decrement it to 1096 and so on Important PWM will be perfect to control how fast your robot will move or how fast a fan is spinning A pin with PWM signal can power an LED just fine This is not the case if we are controlling something with high power demands like a motor or a light bulb In this case we would need to use the PWM signal to control a circuitry and that circuitry will supply the needed power to the device For example H bridge circuits are most commonly used to control the speed and direction of motors Important not
151. t is created and not released then this object is using resources from the system that will never be freed The most common symptom is memory leaks A program that is leaking memory will contentiously use more memory till the system run out of memory and probably crash Those bugs are usually very difficult to find in code Modern languages have garbage collector that keeps track of used objects When the system runs low on memory resources the garbage collector jumps in and search through all objects and frees the one with no references Do you remember how we created objects before using the new keyword and then we assigned the object to a reference An object can have multiple references and the garbage collector will not remove the object till it has zero references new object OutputPort Ref1 new OutputPort FEZ Pin Digital LED true second reference for same object OutputPort Ref2 Ref1 lose the first reference Refi null Our object is still referenced it will not be removed yet now remove the second reference Ref2 null from this point on the object is ready to be removed by the garbage collector Note that the object is not removed immediately When needed the Garbage collector will run and remove the object This can be an issue in some rare cases because the garbage collector needs some time to search and remove objects It will only be few milliseconds but what if your app
152. tPort Cpu Pin FEZ Pin Digital LED true Button new InputPort Cpu Pin FEZ_Pin Digital LDR false Port ResistorMode PullUp Copyright O 2010 GHI Electronics LLC Page 46 170 Beginners guide to C and NET Micro Framework C Level B while true LED Write Button Read Thread Sleep 10 Usually there are many way to write the code Use what makes you comfortable and with more experience you will learn how to optimize the code 10 4 Methods and Arguments Methods are actions taken by an object It can also be called a function of an object We have already seen methods and have used them Do you remember object Debug which has Print method We have already used Debug Print many times before where we gave it a string to display in the output window The string we passed is called an argument Methods can take one or more optional arguments but it can only return one optional value The Print method in Debug object only takes one string argument Other method may not require any arguments or may require more than one argument For example a method to draw a circle can take four arguments DrawCircle posx posy diam color An example for returning values can be a method that returns temperature So far we have learned of three variable types int string and bool Will cover other types later but remember that everything we talk about here apply to other variable types The returned valu
153. te that this reference is at this point not referencing to any object no instance assigned just yet so it is referencing NULL To create the new object instance and reference it from Mike Mike new human We now can use any of the human methods on our instance Mike Mike Run distance Mike Eat bool hungry 7 Mike IsHungry We have used those non static methods already when we controlled input and output pins When creating a new non static object the new keyword is used with the constructor of the object The constructor is a special type of method that returns no vale and it is only used when creating construction new objects Static methods are easier to handle because there is only one object that is used directly without creating instances The easiest example is our Debug object There is only one debug object in the NETMF system so using its methods like Print is used directly Debug Print string may not have used the exact definitions of static and instances but wanted to describe it in the simplest possible way 10 8 Constants Some variables may have fixed values that never change What if you accidentally change the value of this variable in your code To protect it from changing add the const keyword before the variable declaration const int hours in one day 24 Copyright O 2010 GHI Electronics LLC Page 50 170 Beginners guide to C and NET Micro Framework C Leve
154. tem On the other hand the real time clock is used to time human time like minutes hours and even dates 21 1 Real Time Clock All GHI NETMF devices have a built in RTC The RTC job is to keep track of time and date Even if the system is off the RTC will be running off a backup battery Keeping RTC running while system is off requires a 32 768Khz oscillator and a 3V coin battery on a specific pin usually called VBAT All GHI boards and modules except FEZ Mini already have 32 768Khz crystal on board Only 3V disc battery is needed It is important to understand that the time services in NETMF is not directly connected to RTC For example you can set the NETMF system time and from that point on time will be accurately available This doesn t mean the RTC hardware has the correct time Also a user maybe reading time from a time server over the network and wanting to use that instead of RTC Here is an example that sets the time first then print the time every 100ms This sets the NETMF time and not RTC hardware Loosing power will cause the clock to reset to a random value using System Threading using Microsoft SPOT using Microsoft SPOT Hardware using System namespace MFConsoleApplicationi public class Program public static void Main 1 set the time to 9 9 2010 at 9 09 09 DateTime time new DateTime 2010 9 9 9 9 9 Utility SetLocalTime time while true Debug Print DateTime Now ToString Thr
155. the button is low when it is pressed So to achieve this we want to invert the state of the LED from the state of the button If the button is pressed low then we want to turn the LED on high LED need to be checked repeatedly so we will do it once every 10ms using System using Microsoft SPOT using System Threading using Microsoft SPOT Hardware using GHIElectronics NETMF FEZ namespace MFConsoleApplication1 public class Program public static void Main OutputPort LED InputPort Button bool button state LED new OutputPort Cpu Pin FEZ Pin Digital LED true Button new InputPort Cpu Pin FEZ Pin Digital LDR false Port ResistorMode PullUp while true button state Button Read if button state true LED Write false if button_state false LED Write true Thread Sleep 1 Copyright 2010 GHI Electronics LLC Page 44 170 Beginners guide to C and NET Micro Framework C Level 2 10 3 if else statements We learned how if statement works Now we want to use else statement Basically if a statement is true the code inside the if statement runs or else the code inside else statement will run With this new statement we can optimize the code above to be like this using System using Microsoft SPOT using System Threading using Microsoft SPOT Hardware using GHIElectronics NETMF FEZ namespace MFConsoleApplication1 public cla
156. they are tolerant of 5V but when the same pin is set to analog only up to 3 3V can be used This limitation of analog inputs is not a big issue usually because most analog signals are conditioned to work with the analog inputs A voltage divider or an op amp circuit can be used to get a fraction of the actual signal scale the signal For example if we want to measure the battery voltage which is 6V then we need to divide the voltage in half using a voltage divider resistor s so the analog pin will only see half the voltage which is 3V max In software we know we have the voltage divided in half so any voltage we see will need to be multiplied by 2 to give us the actual voltage we are trying to measure Luckily GHI implementation of analog inputs already handles signal scaling When constructing a new analog input object optionally you can set the scaling The internal reference is OV to 3 3V so everything you measure needs to take this in mind The easiest is to set the scale to 0 to 3300 You can think of this as millivolts If we read 1000 then the input voltage is 1 volt AnalogIn BatteryVoltage new AnalogIn AnalogIn Pin FEZ Pin AnalogIn AnO9 BatteryVoltage SetLinearScale 3300 int voltage BatteryVoltage Read Remember to use the analog pin enumeration to determine what pins can be used as analog To print the analog value to the debug output in volts we would need to convert the value to volts and then to a st
157. to point connection others require a mesh network The biggest challenge when designing a wireless device is certification Not only this needs to be done for different countries it is very costly You can easily spend 50 000 USD on certifying a wireless device Fortunately there are companies who offer certified wireless modules When using a certified module your product may not need any certification or the certification will be much easier 31 1 Zigbee 802 15 4 Zigbee is designed to be used in low power battery operated sensors Many sensors can connected on one Zigbee network Also it requires very low power but data transfer rate is not very fast One very common implementation of Zigbee is XBee modules offered from Digi There are many types of XBee modules Some are very low power and other provides a very high output capable of transferring data up to 15 miles Those modules are also offered on on board antenna or with a connector for external antenna The modules have a very simple interface that runs on UART With UART the modules can be interfaced to any NETMF device If creating a connection between two modules then XBee modules establish a connection automatically If connecting multiple nodes then we would need to send some serial commands to configure our network suggest you start with automatic point to point connection Connecting XBee to FEZ Mini or FEZ Domino can be easily done using the Xbee expansi
158. to unmount sdPS UnmountFileSystem TE as Thread Sleep Timeout Infinite 23 2 USB Mass Storage Files are handled on USB exactly the same way it is done on SD The only difference is in how we detect a USB device and mount it For SD we could use an input pin to detect the card On USB we use events to detect a new media using System using System IO using System Threading using Microsoft SPOT using Microsoft SPOT IO using GHIElectronics NETMF IO using GHIElectronics NETMF USBHost namespace Test class Program Copyright O 2010 GHI Electronics LLC Page 116 170 Beginners guide to C and NET Micro Framework File System Hold a static reference in case the GC kicks in and disposes it automatically note that we only support one in this example static PersistentStorage ps public static void Main Subscribe to RemovableMedia events RemovableMedia Insert RemovableMedia_ Insert RemovableMedia Eject RemovableMedia Eject Subscribe to USB events USBHostController DeviceConnectedEvent DeviceConnectedEvent Sleep forever Thread Sleep Timeout Infinite static void DeviceConnectedEvent USBH Device device 1 if device TYPE USBH DeviceType MassStorage Debug Print USB Mass Storage detected ps new PersistentStorage device ps MountFileSystem static void RemovableMedia Insert object sender MediaEventArgs e Debug P
159. troller through OutputPort object We first create the object handler reference and then we make a new OutputPort object and assign it to our handler When creating a new OutputPort object you must specify the initial state of the pin 1 or 0 The one and zero can be referred to high or low and also can be true for high and false for low We will make the pin true high in this example to turn on our LED by default Here is the code using the pin number 4 FEZ Domino on board LED using System using Microsoft SPOT using System Threading using Microsoft SPOT Hardware namespace MFConsoleApplication1 public class Program public static void Main OutputPort LED LED new OutputPort Cpu Pin 4 true Thread Sleep Timeout Infinite FEZ SDK comes with FEZMini_GHIElectronics NETMF FEZ and FEZDomino GHlElectronics NETMF FEZ assemblies Add the appropriate assembly to your program then also adds FEZ GHIElectronics NETMF System Now modify the code by adding using GHlIElectronics NETMF FEZ at the top of your code Here is the code this time using the FEZ pin enumeration class using System using Microsoft SPOT using System Threading using Microsoft SPOT Hardware using GHIElectronics NETMF FEZ namespace MFConsoleApplication1 public class Program Copyright 2010 GHI Electronics LLC Page 35 170 Beginners guide to C and NET Micro Framework
160. true LED Write LED Read Thread Sleep 20 Copyright 2010 GHI Electronics LLC Page 36 170 Beginners guide to C and NET Micro Framework Digital Input amp Outputy This is another way simpler way to blink an LED using System using Microsoft SPOT using System Threading using Microsoft SPOT Hardware using GHIElectronics NETMF FEZ namespace MFConsoleApplication1 public class Program public static void Main OutputPort LED LED new OutputPort Cpu Pin FEZ Pin Digital LED true while true LED Write true Thread Sleep 2 LED Write false Thread Sleep 200 Let see if you can change the sleep time to make the LED blink faster or slower Also try to use a different value for its state so it is on for long time and then it is off for short time Important note Never connect two output pins together If they are connected and one is set to high and the other is set to low you will damage the processor Always connect an output pin to an input driving circuit or a simple load like an LED 9 2 Digital Inputs Digital inputs sense if the state of its pin is high or low There is limitation on these input pins For example the minimum voltage on the pin is O volts A negative voltage may damage the pin or the processor Also the maximum you can supply to the pin must be less than the processor power source voltage All GHI Electronics boards us
161. ts listed below To determine whether you need a COM port read the documentation that came with your Bluetooth device Port Direction Name Q Add COM Port Select the type of COM serial port that you want to add Incoming device initiates the connection Outgoing computer initiates the connection Device that will use the COM port Browse On the embedded side there are many serial modules that already include Bluetooth hardware and software including SPP Serial Port Profile Those can easily connect to any NETMF device s serial port We e Connecting Bluetooth to FEZ Mini or FEZ Domino can me be easily done using the Bluetooth interface component STATUS E ang i1 Er Copyright O 2010 GHI Electronics LLC Page 157 170 Beginners guide to C and NET Micro Framework Wireless 31 3 Nordic Nordic semiconductor created it own digital wireless chips NRF24L01 These low power chips use 2 4Ghz which is a free band in many countries Nordic wireless chips allow point to point or multi point wireless connections Olimex offers breakout boards for NRF24L01 Those boards can connect directly to most GHI s NETMF boards This is a project and video showing two NETMF devices using NRF24L01 http www microframeworkprojects com index php title SimpleWireless Copyright 2010 GHI Electronics LLC Page 158 170 Beginners guide to C and NET Micro Framework Obje
162. ug Print Looping i times while i gt 0 Check if connected to PC if USBClientController GetState USBClientController State Running Note Mouse X Y are reported as change in position relative position not absolute factor diameter ANGLE STEP SIZE int System Math PI 180 2 int dx 1 factor int Microsoft SPOT Math Sin angle 1000 int dy factor int Microsoft SPOT Math Cos angle 1000 angle ANGLE STEP SIZE diameter diameterIncrease if diameter gt MAX CIRCLE DIAMETER diameter lt MIN_CIRCLE_DIAMETER diameterIncrease 1 report mouse position mouse SendData dx dy 0 USBC Mouse Buttons BUTTON NONE Thread Sleep 10 28 4 Keyboard Emulating a keyboard is as easy as emulating a mouse The following example will create a USB Keyboard and send Hello world to a PC every second using System using System Threading using Microsoft SPOT using Microsoft SPOT Hardware Copyright O 2010 GHI Electronics LLC Page 140 170 Beginners guide to C and NET Micro Framework USB Clieng using GHIElectronics NETMF USBClient using GHIElectronics NETMF Hardware public class Program public static void Main Check debug interface if Configuration DebugInterface GetCurrent Configuration DebugInterface Port USB1 throw new InvalidOperationException Current debug interface is USB It m
163. ust be changed to something else before proceeding Refer to your platform user manual to change the debug interface Start keyboard USBC Keyboard kb USBClientController StandardDevices StartKeyboard Debug Print Waiting to connect to PC Send Hello world every second while true Check if connected to PC if USBClientController GetState USBClientController State Running We need shift down for capital H kb KeyDown USBC_Key LeftShift kb KeyTap USBC Key H kb KeyUp USBC Key LeftShift Now ello world kb KeyTap USBC Key E kb KeyTap USBC Key L kb KeyTap USBC Key L kb KeyTap USBC_Key 0 kb KeyTap USBC Key Space kb KeyTap USBC Key W kb KeyTap USBC Key 0 kb KeyTap USBC Key R kb KeyTap USBC Key L kb KeyTap USBC Key D The I kb KeyDown USBC Key LeftShift kb KeyTap USBC Key D1 kb KeyUp USBC Key LeftShift Send an enter key kb KeyTap USBC Key Enter Thread Sleep 1000 j Copyright O 2010 GHI Electronics LLC Page 141 170 Beginners guide to C and NET Micro Framework USB Clieng 28 5 CDC Virtual Serial Serial ports are the most common interface especially on the embedded system world This is an ideal solution for devices to transfer data between PCs and embedded devices FEZ To combine the popularity and usefulness of USB with the easiness of serial we have virtual USB devices To windows applications or to devices a virtual serial port
164. ver is based on transactions If we want to read from a register on a sensor we would need to send it the register number and then we need to read the register Those are two transactions write then read This example will send communicate with I2C device address 0x38 It will write two register number and read back the register value using System using Microsoft SPOT using Microsoft SPOT Hardware namespace Test public class Program public static void Main create I2C object I2CDevice Configuration con new I2CDevice Configuration 0x38 400 I2CDevice MyI2C new I2CDevice con create transactions we need 2 in this example I2CDevice I2CTransaction xActions new I2CDevice I2CTransaction 2 create write buffer we need one byte byte RegisterNum new byte 1 2 X xActions 0 MyI2C CreateWriteTransaction RegisterNum create read buffer to read the register byte RegisterValue new byte 1 xActions 1 MyI2C CreateReadTransaction RegisterValue Copyright O 2010 GHI Electronics LLC Page 82 170 Beginners guide to C and NET Micro Framework Serial Interfacesg Now we access the I2C bus and timeout in one second if no responce MyI2C Execute xActions 1000 Debug Print Register value RegisterValue 0 ToString 17 4 One Wire GHI exclusively supports one wire devices on NETMF Dallas semiconductors one wire devices like temperature
165. walk but do they walk the same way When you call walk method in C then it is not clear if the cat or the human will walk but using human walk or cat walk makes it clearer Creating classes is beyond the scope of this book Here is a very simple class to get you started class MyClass int Add int a int b return a b 10 6 Public vs Private Methods can be private to a class or publicly accessible This is useful only to make the objects more robust from programmer misuse If you create an object class and this object has methods that you do not anyone to use externally then add the keyword private before the method return type otherwise add the public keyword Here is a quick example class MyClass public int Add int a int b the object can use private methods inside the class only DoSomething return a b private void DoSomething Copyright 2010 GHI Electronics LLC Page 49 170 Beginners guide to C and NET Micro Framework C Level 2 10 7 Static vs non static Some objects in life have multiple instances but others only exist once The objects with multiple instances are non static For example an object representing a human doesn t mean much You will need an instance of this object to represent one human So this will be something like human Mike We now have a reference called Mike of type human It is important to no
166. want to run it on the emulator Let us make sure you have everything setup properly Click on Project gt Properties from the menu In the new showing window we want to make sure we select the emulator On the left side tabs select NET Micro Framework and make sure the window looks like the image below Transport Emulator X Solution Explorer 4 Body ay WE v c d Y Nov l vy ca r XE MFConsoleApplication Program cs Start Page o o S Application T Deployment Build Transport Build Events Emulator Y Debug Device Resources Microsoft Emulator v Services E Generate native stubs for internal methods Settings Root name for native stub files Reference Paths NET Micro Framework Create stub files in this directory n m alag A Solution MFConso S 9l MFConsoleApp B E Properties 6 s3ij References Program cs H Gl Resources re 4 m Properties l Copyright 2010 GHI Electronics LLC Page 16 170 Beginners guide to C and NET Micro Framework Getting Startedy Device Microsoft Emulator Make sure the output window is visible click on View gt Output Executing Finally we are ready to run our first application Press F5 key on the computer This is a very useful shortcut and you will be using it a lot to run your applications After you press F5 the application will be compiled and loaded on the emulator and in c
167. x27 0x40 0xa9 0x15 Oxbd Oxfa 0xac 0x45 Oxb1 Oxb8 Oxel 0x7d Oxf7 Ox8b Ox6c Oxbd Oxd5 0xe3 Oxf4 0x08 0x83 Oxde Oxd6 Ox4b OxdO Ox6c 0x76 0x65 0x17 0x52 Oxaf Ox1c 0x50 Oxff 0x10 Oxe8 Ox4f Ox4f 0x96 0x99 0Ox5e Ox24 Ox4c Oxfd 0x60 Oxbe 0x00 Oxdc 0x07 0x50 Ox6d Oxfd Oxcb 0x70 Ox9c 0xe6 Oxb1 Oxaf Oxdb Oxca 0x7e 0x91 0x36 Oxd4 Ox2b Oxf9 0x51 Ox6c 0x33 Oxcf Oxbf Oxdd 0x69 Oxfc 0x49 0x87 Ox3e Ox1f 0x76 0x20 0x53 0Oxc6 0x2e 0x37 Oxfa 0x83 Ox3d OxfO Oxdc 0x16 Ox3f 0x16 Oxe8 0Ox0e Oxa4 Oxcf Oxcf Ox2f 0x77 Ox6c Ox1b Oxel 0x88 Oxbd 0x32 Oxbf 0x95 0Ox2f 0x86 Oxbb Oxf9 Oxb4 0x42 Oxcd Oxae 0xOb 0x92 0x6a 0x74 0xa0 Oxaf x5a Oxf9 Oxb3 0x75 0xa3 the private key for dycrypting byte private key new byte xb9 0Ox1c 0x24 0xca 0xc8 Oxe8 Ox3d 0x35 0x60 Oxfc 0x76 Oxb5 0x71 0x49 0xa5 OxOe Oxdd Oxc8 Ox 6b 0x34 0x23 0x94 0x78 0x65 0x48 Ox5a 0x54 Ox71 Oxd4 Oxla 0x35 0x20 0x00 Oxc6 Ox c 0x04 Ox7e OxfO 0x34 Ox8f 0x66 Ox7f Ox8a 0x29 Oxe2 0x5be Oxe5 0x39 0x60 0x15 0x01 0x58 Ox2b xc 0x92 Oxcd Ox41 0x75 Ox1b 0x33 0x49 0x78 0x20 0x51 0x19 Ox3b 0x26 Oxaf 0x98 Oxa5 Ox4d 0x14 Oxe7 Ox2f 0x95 0x36 Oxd4 Ox a Ox3b Oxcf 0x95 0x25 Oxbb 0x23 0x43 Ox8f 0x99 Oxed O xb8 0x35 Oxe4d 0x86 0x52 0x95 Ox3a Oxf5 0x36 Oxba 0x48 0x3c 0x35 0x93 Oxac 0xa8 O0xbO Oxba Oxb
168. y The code represent the our earlier XML example Copyright 2010 GHI Electronics LLC Page 129 170 Beginners guide to C and NET Micro Framework XML using System IO using System Xml using System Ext Xml using Microsoft SPOT public class Program public static void Main MemoryStream ms new MemoryStream XmlWriter xmlwrite XmlWriter Create ms xmlwrite WriteProcessingInstruction xml versionzV 1 0V encoding utf 8 xmlwrite WriteComment This is just a comment xmlwrite WriteStartElement NETMF DataLogger root element xmlwrite WriteStartElement FileName child element xmlwrite WriteString Data xmlwrite WriteEndElement xmlwrite WriteStartElement FileExt xmlwrite WriteString txt xmlwrite WriteEndElement xmlwrite WriteStartElement SampleFeq xmlwrite WriteString 10 xmlwrite WriteEndElement xmlwrite WriteEndElement end the root element xmlwrite Flush xmlwrite Close display the XML data byte byteArray ms ToArray char cc System Text UTF8Encoding UTF8 GetChars byteArray string str new string cc Debug Print str Important note On NETMF XML writer and XML reader libraries are available from two different libraries The XML reader comes from assembly System Xml but the XML writer comes from MFDpwsExtensions If you want to know why then you need to check with Microsoft Also the XML rea
169. y can be perfect to activate a Piezo We will always use duty cycle of 50 but we will change the frequency to get different tones When connecting a Piezo make sure that it its polarity is correct plus goes to PWM signal and minus goes to ground See the FEZ Piezo speaker component on www TinyCLR com This is a project that decodes a MIDI file from a SD card then plays the main tone on a piezo http www microframeworkprojects com index php titleZPWM MIDI Player Copyright O 2010 GHI Electronics LLC Page 59 170 Beginners guide to C and NET Micro Framework Glitch filteg 13 Glitch filter When we used the button earlier section 9 2 we set it up so when it is pressed the pin value is low otherwise it is high When you flip a witch or press a button the button or switch can bounce when it is pressed In other words the button generates few on and off before it is settled This will make it look like if the button was pressed few times Those few on off bounces come for a very short time To eliminate them in hardware we can add a capacitor between the pin and ground To handle this in software we check the time between button presses if it is a short time then this is a glitch and so it needs to be ignored A user can press the button on and off maybe every 200 ms So if the time between presses is 10ms then we know the user couldn t have possible pressed it so fast and for that this is a glitch and we need to glitch filt
170. you forgot what is a reference then go back and read more in C Level 2 chapter To create the object we use new keyword and then we need to tell it the size of our array This size is the count of how many elements on the type we will have in a n array Our type is a byte and so the number is how many bytes we are allocating in memory byte MyArray MyArray new byte 10 We have created a byte array with 10 elements in it The array object is referenced from MyArray We now can store read any of the 10 values in the array by indicating which index we want to access byte MyArray MyArray new byte 10 MyArray 0 123 first index MyArray 9 99 last index MyArray 10 1 This is BAD ERROR A very important note here is that indexes start from zero So if we have an array of size 10 then we have indexes from 0 to 9 Accessing index 10 will NOT work and will raise an exception Copyright O 2010 GHI Electronics LLC Page 69 170 Beginners guide to C and NET Micro Framework C Level 35 We can assign values to elements in an array at the time of initialization This example will store the numbers 1 to 10 in indexes 0 to 9 byte MyArray new byte 10 1 2 3 4 5 6 7 8 9 10 To copy an array use the Array class as follows byte MyArray1 new byte 10 1 2 3 4 5 6 7 8 9 10 byte MyArray2 new byte 10 Array Copy MyArray1 MyArray2 5
171. yte array Three objects for sending one byte This is okay if you only need to do this a few times at initialization stage but if you are continuously using the WriteRegister method then this is not the right way For starters this method will run very slow so you wouldn t be able to WriteRegister fast enough Maybe this is sending graphics to the display or sending MP3 data to a decoder This means that our function will be called few thousand times every second As second problem is that these objects are created used and then left for the garbage collector to remove The garbage collector will have to jump in and remove all these unused objects from memory which will stop the program execution for few milliseconds Here is the code modified to test the method when called 1000 times using System Threading using System using Microsoft SPOT Hardware using Microsoft SPOT namespace MFConsoleApplicationi public class Program static void WriteRegister byte register_num byte value SPI _spi new SPI new SPI Configuration Cpu Pin GPIO NONE false 0 0 false true 1000 SPI SPI module SPI1 byte buffer new byte 2 Copyright O 2010 GHI Electronics LLC Page 164 170 Beginners guide to C and NET Micro Framework Thinking Small buffer 0 register num buffer 1 value _spi Write buffer _spi Dispose public static void Main long ms long ticks DateTime Now Ticks for int i 0

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