PIC-USB40 User Manual
Contents
1. A1 46 3F 6B 5D 14 C6 65 41 61 5B 38 56 50 E4 BA 34 1D 31 2F AC E8 AF 22 C3 7F_ F5 65 C4 A1 50 1F B6 80 7D 00 EC BD 97 FD BC 45 Al 11 B5 94 6D 3A 7C 7B 1B C5 2F 1C AC C4 07 94 68 75 51 FO E4 2D 56 14 EA 11 C8 A6 A3 2C BO 6D 6E CF DC 17 A2 2E C9 OB 43 2D 34 BA BE OE 49 3D 74 84 F9 C3 52 37 B OD F8 26 A1 C9 D3 99 OC E2 Data Address MSB 0 1 2 3 4 5 6 7 8 9 A B C D E F Tools Status Idle The data display All Data and addresses are displayed in hexadecimal The least significant bits of the address are shown along the top columns and the most significant bits of the address are shown along the left hand side of the rows In the screenshot above the LSB 5 and the MSB A so the hexadecimal address of the data is A5 Double clicking on a data cell allows you to edit the memory location The data must be entered in hexadecimal Status Indicates if the programming or verify was completed successfully or not Tools Menu Load Data Loads a comma delimited file into the data display CSV can be imported and exported from various spreadsheet applications Save Data Saves the data display as a comma delimited file Write Data Memory Downloads the contents of the data display to the EEPROM Data memory of the microcontroller Kelvyn Shaw 2009 Page 6 Verify Data Memory Verifies that the contents of the data display matches the EE2. MOVLW B 10010000 MOVWE RCSTA MOVLW B 00001000 MOVWF BAUDCON MOVLW 86 MOVWF SPBRG CLRF SPBRGH Kelvyn Shaw 2009 set RX pin as input set TX pin as input which will be change to output 3115200 baud for 40MHz clock Page 9
3. RC2 Digital input output port C bit 2 Capture and compare output 1 PWM output 1 RC3 Digital input output port C bit 3 SPI clock 12C clock RC4 Digital input output port C bit 4 SPI data input 12C data RC5 Digital input output port C bit 5 SPI data output RDO Digital input output port D bit 0 PSP bit 0 RD1 Digital input output port D bit 1 PSP bit 1 RD2 Digital input output port D bit 2 PSP bit 2 RD3 Digital input output port D bit 3 PSP bit 3 RD4 Digital input output port D bit 4 PSP bit 4 RD5 Digital input output port D bit 5 PSP bit 5 RD6 Digital input output port D bit 6 PSP bit 6 RE7 Digital input output port D bit 7 PSP bit 7 REO Digital input output port E bit 0 Analogue input AN5 PSP RD RE1 Digital input output port E bit 1 Analogue input AN6 PSP WR RE2 Digital input output port E bit 2 Analogue input AN7 PSP CS RE3 Digital input port E bit 3 Reset input Programming MCLR input Kelvyn Shaw 2009 Page 2 Powering the module The module can be powered from the USB connection which falls into two categories or from an external power supply Low Power USB powered The USB bus provides power for the whole circuit The circuit must draw less than 100mA from the bus High Power USB powered The USB bus provides power for the whole circuit The circuit must draw less than 500mA from the bus Self Powered The circuit is powered from its own power supply and therefore has not restri
4. An output from the USB interface that goes low when the USB interface goes into suspend mode Can be used to power down external circuitry RTS Request to Send An RS232 handshake signal output from the USB interface CTS Clear to Send An RS232 handshake signal input to the USB interface LED1 Lights red to indicate the USB interface is transmitting data to the microcontroller LED2 Lights green to indicate the USB interface is receiving data from the microcontroller Microcontroller Connections and main uses RAO Digital input output port A bit 0 Analogue input ANO RA1 Digital input output port A bit 1 Analogue input AN1 RA2 Digital input output port A bit 2 Analogue input AN2 RA3 Digital input output port A bit 3 Analogue input AN3 RA4 Digital input output port A bit 4 TimerO clock input RAS Digital input output port A bit 5 Analogue input AN4 RBO Digital input output port B bit 0 Interrupt input 0 RB1 Digital input output port B bit 1 Interrupt input 1 RB2 Digital input output port B bit 2 Interrupt input 2 RB3 Digital input output port B bit 3 RB4 Digital input output port B bit 4 RB5 Digital input output port B bit 5 RB6 Digital input output port B bit 6 Programming Clock Input RB7 Digital input output port B bit 7 Programming Data Input RCO Digital input output port C bit 0 Timer 1 oscillator output Timer 1 3 clock input RC1 Digital input output port C bit 1 Timer 2 oscillator input
5. PIC USB40 User Manual Description The module is a single board controller containing an 18F4520 PIC microcontroller and a USB interface based on FTDI s FT232R interface IC The USB interface IC takes care of all the USB interfacing protocol and is interfaced to the microcontroller via an RS232 transmit and receive connection No USB knowledge or programming is needed to interface the microcontroller to the PC which frees up resources in the microcontroller and eases USB interface development The module has an onboard type B USB connecter and 40 pin turned pin connecter on a 0 1 pitch to enable mounting on veroboard or breadboard for development The microcontroller is pre programmed with a bootloader to enable you to program the module from a USB connection with the supplied bootloader software The case may be that you don t need USB connectivity and just use the USB connection for programming the microcontroller The microcontroller can also be programmed in a standard way without the use of the bootloader using a dedicated programmer such as Microchips Pickit programmer with connection to pins 1 5 of the module The module contains a 10MHz crystal for the microcontroller to run in HS PLL mode and run with an instruction cycle of 40MIPS There is an onboard reset button to reset the microcontroller at any time with the USB interface also interfacing to the reset so that the microcontroller can also be reset from the PC application side Onboard
6. PROM data memory of the microcontroller Read Data Memory Uploads the contents of the microcontrollers EEPROM Data memory to the data display Exit Close down the EEPROM Data editor window Writing programs for the module when not using the bootloader If you don t plan on using the bootloader and you are going to use a standard programmer to program the microcontroller then the only considerations to be made are the oscillator the reset pin and the TX RX pins The oscillator for the module uses a 10MHz crystal and can be used to run the system clock at 10MHz with an instruction cycle of 2 5 MIPS or 40MHz with an instruction cycle of 10 MIPS with the use of the PLL To do this you need one of the following lines in the assembly listing when using MPLAB config OSC HS system clock will run at 1OMHz or config OSC HSPLL system clock will run at 40MHz To use the reset button on the module then RE3 pin must the setup to do so by add the following line in the assembly listings Config MCLRE ON set s RE pin to be used as reset Pins RC7 and RC6 of the microcontroller are connected to the transmit and receive pins of the USB interface IC If the USB interface isn t used then RC6 is best set to and output and set low RC7 is best set as an input Writing programs for the module using the bootloader When writing programs using the bootloader you must consider the following Program memory interupt and reset vectors The fi
7. ctions on the current it draws and also is able to operate without an USB connection However the module is powered the USB interface part of the circuit based around IC2 is always powered from the USB port This makes sense as the circuit doesn t ever need to be powered unless it is connected to a USB connection This part of the circuit draws approx 15mA from the USB hub when running and 70UA when in suspend mode If your circuit needs to operate when not connected to USB then it has no option but to be self powered If your circuit draws more than 500mA then it must be self powered If your circuit draws less than 100mA then it can be powered from the any USB connection If your circuit draws less than 500mA but more than 100mA then it can be powered from USB as long as it is not connected to a hub that isn t self powered and therefore not capable of providing 500mA Also your circuit must not draw more than 100mA until the host has configured the USB connection External power supply and onboard regulator The onboard regulator regulates the voltage to microcontroller to 5V A mosfet switch also provides switching between the USB and external power When powering the module from USB then without an external power supply then the USB voltage supply from the USB bus V USB will be connected to the microcontroller power supply V PIC When the USB interface is put into USB suspend mode then the mosfet will switch off power to the microcontrolle
8. ge to V REG pin Maximum Current through regulator 15V 0 13A 12V 0 18A 9V 0 32A 8V 0 42A 6V 0 65A 5V 1 0A Programming the module using Microchips PicKit programmer If you dot want to use the bootloader to download programs through the USB interface then the microcontroller can be programmed using a standard programmer such as Microchip s PicKit 2 programmer Connect as shown in the diagram with pin 1 of the programmer lining up with pin 1 of the module In this case the bootloader will be over written If you want to restore the bootloader then the Hex file for the bootloader can be download from our website and reprogrammed into the microcontroller RE3 V PIC OV Ground RB7 RB6 Pins 1 6 of RBS the module PicKit 2 Programming the module using the bootloader software The USB bootloader software can be used to download programs via the USB interface without the need for any special programming equipment When a module is connected to a USB port it will be detected by the bootloader software A hex file that is created from Microchip s MPLAB or other development software can be loaded from the PC and downloaded to the microcontroller The bootloader firmware in the microcontroller takes up 2K of the 32K program memory and is write protected to prevent being overwritten The Software initializes the bootloader in the microcontroller by first resetting the microcontroller and then issuing a command though
9. it enabled Brown out reset voltage minimum setting Power up timer Enabled Watchdog timer controlled by software SWDTEN bit enabled Watchdog timer postscaler 32768 MCLR pin Enabled RE input pin disabled Low power timer1 oscillator configured for high power operation PORTB A D Disabled CCP2 multiplexed RC1 Background Debugger Disabled Extended instruction set Disabled Single supply ICSP Disabled Stack full or underflow reset will not cause reset All code protection is disabled to all addresses All table read protection is disabled to all addresses All table write protection is disabled to all addresses except the boot block 0000h 07FFh Watchdog Timer And Brown out Control From Software The watchdog timer and brown out functions are setup in the configuration bits to be controlled by the user s software Use the following assembly code to enable and disable the watchdog timer and brown out reset BSF WDTCON SWDTEN enable watchdog timer BCF WDTCON SWDTEN disable watchdog timer BSF RCON SBOREN enable brown out reset BCF RCON SBOREN disable brown out reset Kelvyn Shaw 2009 Page 8 Setting up communications with the USB Interface The following assembly code will setup the microcontroller for RS232 communication with the USB interface at a baud rate of 115 2Kbps This is the same rate that is used by the bootloader BSF TRISC 7 BSF TRISC 6 when transmitter enabled MOVLW B 10100100 MOVWE TXSTA
10. r Any external circuitry can take power from V PIC and will be then be disabled when in USB suspend mode The mosfet switch can provide a maximum current of 2A When the module is self powered then an external supply is feed into V REG and the mosfet switch will switch off to stop V USB being connected to V PIC There will be no effect on the power to the microcontroller V PIC when in USB suspend mode when be powered from an external power supply If the module is self powered and then connected to a USB bus then the module will remain being self powered unless the power supply is removed and then the module will switch to being powered from the USB bus If the module is being powered from the USB bus and an external supply is added then this will have no effect and the module will continue to take its power from the USB bus until the USB connection is removed and the module will switch to being self powered from the external power supply Maximum regulator current at various supply voltages The output of the regulator V PIC is set to 5V Then input to the regulator V REG can be from 5V to 15V There is a voltage drop of approx 0 3V by the regulator so if a 5V power supply is used then the regulator output will be approx 4 7V which is still fine for powering the microcontroller The table below shows the maximum current the regulator can handle at various supply voltages Kelvyn Shaw 2009 Page 3 Supply Volta
11. rst 2K of the 32K program memory is used for the bootloader The bootloader firmware takes up program memory address 0000h to 07FFh and is write protected The interrupt and reset vectors are remapped as follows Reset vector at address 0000h is remapped to address 0800h High priority interrupt vector at address 0008h is remapped to address 0808h Low priority interrupt vector at address 0018h is remapped to address 0818h For example on a high priority interrupt the program will jump to the address 0808h instead of the usual 0008h address General purpose RAM memory There are no RAM memory restrictions for your program The bootloader does use a large amount of RAM when in use but is then freed up when the bootloader is no longer being used The only consideration for the RAM is that if a reset arises in your program then due to the bootloader initialization routine the first 3 bytes of RAM H 00 to H 02 lost during this routine Kelvyn Shaw 2009 Page 7 Reset Delay When a reset happens then there will be a 275mS delay between the reset and you program starting This is due to an initialization routine of the bootloader Configuration Setup The following is the default configuration setup for the microcontroller with bootloader Oscillator switch over mode Disabled Fail safe clock monitor Enabled Oscillator High speed oscillator with PLL oscillator will run at 40MHz Brown out reset controlled by software SBOREN b
12. t the USB to put the microcontroller into download mode If this command isn t received by the microcontroller within 300mS of the reset then the microcontroller comes out of the bootloader memory and starts running the main program as normal Kelvyn Shaw 2009 Page 4 Main Screen Layout EE KS Projects USB Bootloader Target Device Filename Tools Status Idle Target Device Displays the name and serial number of the device connected to the USB port Only one device can be connected at any one time Filename Displays the path and filename of the hex file which will be downloaded to the microcontroller Status Indicates if the programming or verify was completed successfully or not Tools Menu Load File Select a hex file from the PC to be programmed Write Program Memory Downloads the currently selected Hex file to the microcontroller Each time you write program memory the hex file will be reloaded in case it has been updated Verify Program Memory Verifies that the selected hex file matches the program memory of the microcontroller Reset Device Resets the microcontroller by momentarily pulling down the MCLR pin Edit EEPROM Memory Loads the EEPROM editor screen Kelvyn Shaw 2009 Page 5 EEPROM Data Editor layout EEPROM Data Editor Data Address LSB 1 2 3 4 5 6 8 J9 4D SE C8 7A 76 16 CF BB 9E B6 24 FC 5E 62 15 EA 63 44 89 D1 AD 84 F6 EA 88 EF 18 B2
13. transmit and receive LED s provide visual indication of data flow between the USB interface and the microcontroller The module can be powered purely from the USB connection or from an external power supply between 5V to 15V using the onboard regulator Layout and pin descriptions RE3 V Reg V PIC o OV Ground OV Ground USB o V USB RB7 Connector Sleep RB6 o RTS RB5 o CTS RB4 RD7 RB3 O o RD6 RB2 LED1 LED2 o RD5 RB1 o RD4 RBO o RD3 RA5 o RD2 RA4 RD1 RAS RDO RA2 o RC5 RA1 RC4 RAO o RC3 RE2 o o RC2 perje gest f Res REO o RCO Kelvyn Shaw 2009 Page 1 Power Connections V Reg Main regulator input from 5 to 15 volts d c The regulator regulates to 5V and has a dropout voltage of approx 0 3V The regulator provides a 5V regulated power supply to the PIC microcontroller V PIC 5V Output of the regulator to supply external circuitry This is also Vdd power supply to the PIC microcontroller If an external power supply is feed into this pin then it must not be more than 5 5V V USB 5V output from the USB connection The 5V is taken from the PC and care must be taken for how much current is drawn from this pin If the module is not connected to a USB port then this connection will be volt free OV Ground Ground negative common connection to the whole circuit USB Connections and LED s Sleep
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