Home

NorthTek

1. No upside cr else dup char 6 literal bomb else drop bad choice cr then then then then then then r if if if go home red signon black game begin key dup 27 0 while game repeat r home 52 7 2 Setup Magnetic Variation with Position This application sets up the latitude longitude altitude and day and executes the world magnetic model Finally it prints the computed magnetic variation using the internal world magnetic model lat 29 13 set drop lonG 81 33 set drop alt 20 0 set drop day 2011 4 set drop set_wmm 1 set drop magvar di wmmGD di 5 1 237 3 Turtle This application illustrates evaluating the sensor data with NPL In this case the device will print a warning if the compass is upside down for more than 5 seconds To run this program after download type turtle lt CR gt To unload this program type forget read_z lt CR gt Turn turtle script sends an alarm is the compass is upside down for more than 5 seconds forget read z read z accelr amp di 8 get the raw accel array read the z channel r 130 7546 001 Rev A 25 Specifications subject to change without notice IN 2 spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electroni
2. Hello world For this example the b will be used to show the required and non required whitespaces bgreet b bstart a new word called greet bHello World b bmake it print the standard cr b boutput a carriage return b bfinish the word Now execute it greet lt CR gt Hello World OK This example can be done multiple ways to illustrate the free form nature of the language greet Hello world cr as a single line greet Hello World cr as two lines note required whitespace between cr and 5 212 Passing arguments to a function All operators expect a stack based argument The arguments can be compile in or passed at execution time For example to add 2 2 twoplustwo 2 2 add and print 2 and 2 execute it twoplustwo lt cr gt 4 OK Can also be 130 7546 001 RevA 16 A Specifications subject to change without notice 1e S P a CCO N NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics plustwo 2 expects the argument on the stack at runtime execute it note pass one of the arguments now at runtime 2 plustwo lt cr gt 4 OK Finally both args at runtime plus expect both execute it 2 2 plus lt cr gt 4 OK 5 L213 if then else The if clause is slig
3. for error check printit matrix cr m boresightMatrixX cr di boresightMatrixY cr di boresightMatrixZ cr di r This word computes the boresight matrix in place doit orientation 0 set set the orientation back to default 5000 delay wait 5 seconds to allow the estimates to catch up compute compute new boresight matrix copyit put back in the database 130 7546 001 Rev A 29 aN e spartom NAVIGATION AND EXPLORATION Specifications subject to change without notice The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics printit sanity check printout doit run this macro automatically at download forget matrix automatically unload this program 5 1 2 8 Programmer to Programmer This section is addressed to the programmer software engineer or other software professional that wants to use NPL or Remote Function Select RFS in the compass e NPLis a good method for experimenting with the compass manually The ability to make words quickly allows rapid experimentation e RFS is the best method going forward for an automatic interface There is a little more work to create the packet structure but once it is done you will be able to adapt to new variables almost instantly and also interoperate with other products in the product line Al
4. e There isa delay function that takes msecs as an argument It comes in handy e Prototype a bunch of words that do the functions you want then store them as text files and send them with the terminal emulator be careful at 115200 as you can overflow the input stream it is helpful to set a few 5 msec line delay in the terminal emulator when sending files of more than a few lines That way you won t have to type the same things over and over again to do the same things This is especially time saving if you are doing the same thing to a bunch of different devices like testing or calibrating e words shows all the words in the wordlist minus the core words Type loud to allow words to show all the words in the base wordlists Type quiet to go back to the minimum set e grep will search even the hidden wordlists regardless of the state of Loud or quiet remember that everything is case sensitive so if you grep points but the variable is myPoints it won t find it Try grep oints or some other part of the string There is no i option on NPL grep e There are some extensions to Forth in NPL You can enter string interactively but not compiled there are other words for compiled strings What gets left on the stack is a pointer to a counted string This is occasionally useful Similarly the word array v1 v2 v3 Jarray leaves a pointer on the stack to the array v1 v2 v3 It s transient so the next array or
5. s not in the NPL variable space etc etc it is designed to and will crash hard enough that you have to reset You won t lose any permanent calibration data but you can make it stop operating properly It is a useful tool but if NPL was a car it would be a Shelby Cobra not a 12 airbag 97 horsepower hybrid 130 7546 001 RevA 31 Specifications subject to change without notice aN e spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics e Sparton may be able to help with complex applications where NPL may be used in the solution Contact someone at Sparton Tech Support if you have such a need 130 7546 001 RevA 32 TA Specifications subject to change without notice e S pP a CtoO N NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics Appendices A NPL Command Categories NPL is a full programming language in addition to being a command line interpreter Forth commands exist in multiple categories as described in this section The user is directed at the various Forth tutorials on the Internet for a primer on basic Forth c
6. 044259e 03 5 1 1 4 General Examples NPL is capable of fixed and floating point arithmetic bitwise logical operations and many other useful calculator type commands Here are some simple examples For the readers convenience the inputs are commented in NPL style Simple Arithmetic 1 1 push 1 push 1 add the top two items 130 7546 001 RevA 15 Specifications subject to change without notice aN e spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics from the top of the stack and print 2 OK 10 4 push 10 push 4 subtract 4 from 10 and print 6 OK Arithmetic in other number bases hex 1234 print 0x1234 in hex 1234 OK 1234 decimal push 1234 change NPL I O base to decimal print 0x1234 in decimal 4660 OK 5 1 2 NPL Programming Examples Advanced This section will provide several NPL examples starting with the most basic up to some more advanced topics Given that most software developers like to see well commented examples that provide a sample of single subject the examples will be just that Keep in mind that NPL is just a programming language albeit with postfix notation and a simple delimiter model token whitespace token etc 5 1 2 1 Basic NPL Programming SLZ The Basic
7. Some variables are used as triggers that do not carry any real data but instead cause some action to take place such as evaluation of the World Magnetic Model or the sampling of a calibration point Regardless of whether or not the value is volatile or non volatile or factory settable only or not the compass software provides a uniform method for reading and writing the values A binary method for manipulating the database variables is described in the RFS Protocol Suite documentation NPL provides a more human friendly interactive interface into the database that mirrors the RFS functionality The list of database variables for a particular device can be found in the Software Interface User s Manual for the specific device and will not be completely enumerated in this document This document will provide some examples of NPL programs that use common NavMod variables 4 1 Internal Database Identifier Operations In a NavMod each database variable has a name All the database names are pre defined at startup and are visible in the dictionary Executing a variable name causes NorthTek to leave an internal database identifier IDI on the stack The user cannot manipulate this value directly instead this identifier can be passed to other NPL words to cause an action on that particular variable The list of words that can operate on a database identifier is di The current value of the item is printed in a human friendly form gt default Se
8. Sparton Electronics vl v2 vl v2 v1 stack Makes a copy of the 2 item in the OVER stack to the top of the stack Makes a copy of the top item on the DUP stack Swaps the top two stack items SWAP Rotates the top three items so that ROT the 3 deep item is now on the top of the stack These are commands to do input and output to from the user Command Stack Diagram Notes accelp p magp p gyrop p accel p mag p compass p s p gyro p db d p loud quiet key bl key emit grep words 130 7546 00 keyvalue m r Siea ea ea a T F 0x20 1 Rev i teens subject to change without notice Turns on off the processed accelerometer data Turns on off the processed magnetometer data Turns on off the processed gyro data Turns on off the accelerometer data Turns on off the magnetometer data Turns on off the compass data Turns on off the raw sample data Outputs all raw samples Turns on off the raw gyro data Print the entire database contents Enable or disable database internal debug print statements Debug port output only Enables display of the basic forth words when words is executed Disables display of the basic forth words when words is executed Begin a comment Compile Only compile a string that will be output when this word
9. faster and takes less memory than constant Reminder This is a space character not the letter b The string is a Forth style string with a count byte that contains the number of characters in the string including a trailing null 130 7546 001 RevA 10 Specifications subject to change without notice sn e spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics 2 4 7 Flow Control Flow control is actually a compass function but nevertheless applies to the NPL environment When NPL is producing continuous output it may be temporarily suspended by sending lt CTRL S gt and resumed with lt CTRL Q gt This is often helpful in typing a command to disable the streaming output 2 4 8 Quiet and Loud Quiet is a word that suppresses all the Forth primitives when words is executed The word loud restores the Forth primitives to the words display Quiet is the default 2 4 9 Help NPL contains a help facility Some words contain an extended string that provides further description of the word s behavior The syntax is help word If there is a help string associated with that word it will be printed 2 4 10 Grep The NPL wordlist is large The traditional command words to see all the words in the wo
10. interactive human user might need to operate the compass 5 12 21 Flow Control NPL allows the user to temporarily suspend any kind of streaming data The lt ctr1l s gt character is used to suspend output and the lt ctr1l q gt resumes output The user may enter commands in between the characters and interact with NPL as usual however streaming data is suspended For example the command 1 accel p causes the NavMod to emit a continuous output of accelerometer data The user may enter lt ctrl s gt 0 accel p lt ctr1 q gt to stop this output The lt ctrl s gt lt ctr1 q gt pair basically allows you to see what you are typing 51 222 Obtaining Sensor Data The following commands enable the raw and processed sensor data to be streamed out the user port at a high rate For these commands the lt cr gt is not printed 5L 2221 Accelerometer 1 accel p enables print of raw accelerometer readings Output format is A 6d 6d 6d 6d printing timestamp ms x y and z accelerometer values 0 accel p disables 1 accelp p enables print of raw processed acceloremeter readings Output format is AP d d d d F F F printing timestamp ms x y and z accelerometer raw values and x y and z linearized values 0 accelp p disables 51 2222 Gyro 1 gyro p enables print of raw gyroscope readings Output format is G 6d 6d 6d 6d printing timestamp ms x y z values 0 gyro p disables 130 7546 00
11. is executed Returns true if there is a keystroke pending in the input buffer Returns immediately Pushes a blank 0x20 on the stack Waits until a character has been received then returns the character Ouput the number on the top of the stack as a character Ignore the remainder of this line Reads the token following grep attempts to locate commands in the wordlists that contain this substring Case sensitive Display the list of words in the set of wordlists Non destructively print the stack contents Note Always 37 Oy spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein ff decimal hex base lowpower A 4NPL Variables Constants be made without written authorization from Sparton Electronics prints in decimal and hex regardless of the current i o number base formatted floating point print w df format floating point print in e format floating point f format Remove and print the top item from the stack using the current number base Change the current number base to decimal Change the current number base to hex Returns the address of the variable that holds the current number base If true forces the NavMod into low power mode Once low power mode is entered any character received will force the compass to perform a warm start and resume full power ope
12. not words found in the dictionary 130 7546 001 RevA 8 Specifications subject to change without notice aN e spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics stack the terminal value and the initial value The do word marks the top of the loop and the loop word marks the bottom of the loop The do loop structure can only be used inside a word definition on l that is while compiling Inside the loop the word i pushes the current loop index on the stack Thus count 10 0 do i loop defines a word that counts from 0 to 9 that prints the loop index each time Executing count causes the following output 01234567 8 90K In this example the loop ranges are compiled into the word When the word is executed the two values are pushed on the stack and the do word finds the two required loop parameters on the stack when it begins executing However the loop indices may be passed to the count word when it is executed Either one or both may be passed as shown in the following examples countFrom0O 0 do i loop 10 countFrom0 0 123 4 5 6 7 8 9OK countFromMtoN do i loop 20 7 countFromMtoN7 8 9 10 11 12 13 14 15 16 17 18 190K The dictionary grows with each word that is defined T
13. on the serial port setup menu NorthTek prompts the user with an OK when a carriage return is entered this indicates that the interpreter is ready for input Note that the NavMod sensors support multiple protocols on the same serial port Several of the protocols are binary and start command sequences with non printable characters and should not be a problem however the NMEA protocol starts command sequences with a S so if the user accidently begins a line with S the interpreter shifts to NMEA mode until the NMEA closing character is received If this happens the user should simply enter a newline lt CTRL J gt to complete the NMEA command As there is no disk or other mass storage NPL does not implement many of the standard file operations found in a PC based Forth Instead equivalent methods are provided to save and load programs Test programs will be stored on the user s computer and sent to the compass as needed using the file send function built into most popular terminal emulators 2 2 NPL Basics The reader is strongly encouraged to obtain one of the references and learn the basics of the Forth programming language before proceeding However if the references are not immediately available this section will serve as a brief introduction Note that this cannot be a thorough treatise on programming with a new language because as most readers are well aware doing so would cause the size of this document to reach very large
14. only Format GP d d d d 2e 2e 2e r n with arguments timestamp xraw yraw zraw xprocessed yprocessed zprocessed mag p Prints raw magnetics Format M d d d d r n arguments timestamp x y Zz magp p Prints processed magnetics Format MP d d d d f f f f r n arguments timestamp xraw yraw zraw xprocessed yprocess zprocessed yaw magnetic quat p Prints quarternian outputs Format QUAT f f f f r n arguments W X Y Z s p Prints all the raw samples in one line Format GEDC 6 d d d d d d d d d d d r n arguments are timestamp magx magy magz accelx accely accelz gyrox gyroy gyroz temper atureCoefficient Format DC 4 Format d d d d d d 0 0 0 d r n arguments are timestamp magx magy magz accelx accely accelz temperatureCoefficient compass p Prints the computed attitude and heading Format C d 7 2f 7 2f 7 2f r n arguments are timeStamp pitch roll yaw The modulus words expect the modulus value on the top of the stack The modulus words are gyro mod Sets the raw gyro data print modulus Default is 10 This value is volatile and resets to 10 on power up accel mod Sets the accelerometer raw data print modulus Default value is 4 This value is volatile and resets to 4 on power up 130 7546 001 RevA 14 Specifications subject to change without notice aN e spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No pa
15. part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics loop below is a workhorse kind of loop that continues until the user hits escape The second example is a loop that repeats until any key is pressed go begin key dup 27 0 read a key make a copy of it compare it to 27 then invert the logic 0 note the 0 is one token by itself while execute from here to repeat if the key was NOT escape 27 You hit emit cr print the key that the user pressed repeat back to while drop get rid of the spare key when escape was hit all done Try running the example on the NavMod by entering the word and then typing go lt cr gt This loop runs until the user presses any key go2 begin key 0 while Hey Hey Hey cr repeat Also try this on the NavMod by entering the word and typing go2 lt cr gt 5 1 2 1 6 variables NPL allows the declaration of arrays and constants The word variable followed by a name declares a single 32 bit value The value can hold and integer or a float32 Using the variable name returns the pointer to the name The user is required to explicitly read or store using the pointer value Arrays are constucted by allot ing to the end of a variable The user must write the access functions to index the array NPL does not do typed pointers it is the res
16. special words that don t strictly obey the postfix notation of NPL They are i a constant and variable Pronounced colon dot quote constant and variable They are unique in that they expect arguments to follow in the input stream The word colon expects a whitespace delimited token to follow in the stream It begins compilation of a new word in the wordlist The reason that the notation is not postfix is that the token can t already be in the wordlist since it is being currently defined If the as yet non existent token is encountered by the parser it would just print huh and give up on the line of input The colon operator gets around this by looking forward and removing the next token in the input line so the basic parser never sees it Constant and Variable have the same behavior as colon just instead of making the new word an executable word they create a constant or variable respectively Note that constant expects the constant value on the top of the stack before the constant word is executed The word dot quote is often confusing because it appears to violate the whitespace rules However once understood it is simple The word is used to compile in a string to output to the user The word looks ahead in the input buffer just like colon constant and variable do however instead of parsing the tokens by whitespace it parses up to the next quote mark This allows for whitespace in output strings whic
17. terminal program for 115200 8N1 Add 5 milliseconds line delay to the serial port configuration Hyperterminal gt File gt Properties gt Settings Tab gt ASCII Setup TeraTerm Setup gt SerialPort Make sure the new lines are setup for CR 5 Use the file transfer option to send the text file to the compass HyperTerminal Transfer gt Send Text File TeraTerm File gt SendFile 6 Scroll back through the download and look for Huh This is NorthTek s response to something it can t parse or execute Not having the 5 msec line delay is a common cause The Huh response is generally on the offending line and often prints out the offending command 7 Run the program according to the instructions for each program 8 When done unload the program according to the instructions for each program 51 2 7 1 Game This application plays a simple game Make sure that the terminal program is set to VT100 mode After downloading to run this program enter go lt CR gt and follow the commands To unload this program enter forget signon lt CR gt War games forget signon signon cr RU on cr l 1 cr ESNS NITI XN o LEILI J 7 11 I c Tot TIN _I_I __ 7 ex game Would you like to play a game cr 1 Marketing Bingo cr 2 Development Sorry cr 130 7546 001 RevA 23 A Specifications subject to change without notice e Sparton NAVIGATION AND EXPLORATION The content
18. v gt v m v gt r s v gt v s m gt r v gt v be made without written authorization from Sparton Electronics i f 2 cs et fabs f f1 2 1 2 fl 2 1 2 fl 2 1 2 fl 2 1 2 1 2 tf 1 2 tf CEL 2 ct fl 2 tlf EL 2 BE vl v2 vr m v vr vl v2 vr vl v2 vr float TIF vl CyL yg vl v2 v3 m mr vl theta mv mvl wr float vl vr float mmr vl v2 1 Rev F teens subject to change without notice integer convert signed integer to floating point negate a floating point number FNEGATE take the absolute value of a FABS floating point number floating point divide F floating point multiply F floating point subtract F floating point add F Returns true if f1 gt f2 F gt Returns true if f1 lt f2 F lt Returns true if f1 f2 F Returns true if f1 lt f2 Returns true if f1 gt f2 Takes the dot product of v1 and v2 and places the result in vr Takes the three dimensional dot product of matrix m and vector v placing the result in vector vr Takes the cross product of v1 and v2 placing the result in vr Multiplies the elements of v1 by the elements of v2 placing the result in vr Returns true if the value is not equal to zero 1e 20 lt value lt 1e 20 Normalizes v1 in place Performs a 4D normalization o
19. 1 RevA 19 aN Specifications subject to change without notice en SPartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics 1 gyrop p enables print of raw and processed gyro readings Output format is GP d d d d F F F printing timestamp ms x y and z gyro raw values and x y and z linearized values 0 gyrop p disables 5122 23 Magnetometer 1 mag p enables print of raw magnetometer readings Output format is M 6d 6d 6d 6d printing timestamp ms x y and z magnetometer values 0 mag p disables 1 magp p enables print of raw and processed magnetometer readings Output format is MP d d d d F F F printing timestamp ms x y and z magnetometer raw values and x y and z linearized values 0 magp p disables 5 1 2 2 2 4 All raw sensor data 1 s p enables print of all raw sensor data Output format is d d d d d d d d d d d mag x y z accel x y z gyro x y z and raw temp respectively 0 s p disables 51 2225 Computed Roll Pitch and Yaw 1 compass p enables print computed attitude and heading Output format is C d 7 2f 7 2f 7 2f timestamp ms roll pitch and yaw respectively 0 compass p disables 5 1 22 2 6 Comp
20. N orthTek System Programming Manual Applicable to Sparton GEDC 6 and DC 4 Revision 2 1 1 or later ON Ww sparro 5612 Johnson Lake Rd Deleon Springs FL 32130 130 7546 001 Rev A 800 824 0682 386 985 4631 www sparton com ne www thedigitalcompass com The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics REVISION HISTORY DATE DESCRIPTION OF CHANGE INITIALS N 9 22 11 Refactored NorthTek Moved to standalone document N N 10 5 11 Review comments finalized 10 19 11 Spelling corrections and cleaned up artwork 130 7546 001 Rev A 2 Specifications subject to change without notice sn e spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics I SMEPOG UCU ON oe accs hace dececaetren aa aana Eaa E AREA e E eeraa aA aA Raa EEE 4 1 1 What is NorthTek r siseses aonta ene aa a Sake a erare ae aAa aE arenes 4 1 2 How is NorthTek Used iiesici ncn a E a a 4 1 3 Organization and Purpose of this Manual cccccscccssscesssecsessecesececsaeessaaeeseseecsereessaeesssaeeseneeees 4 1 4 Preparations for using NOFthTeK ccccccccss
21. No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics new command in the wordlists with this name begin compiling Finishes compiling finalize the word that was started with in the current wordlist forget 5 Truncate the wordlist back to the FORGET token immediately following the forget word delay v Pauses a program for the given number of milliseconds 41 sparton NAVIGATION AND EXPLORATION 130 7546 001 Rev Ans subject to change without notice
22. Tek allows the printing of the data with some NPL control words The streaming control words are of two types One set enables or disables the streaming output The other set of words changes the number of samples obtain the modulus before raw samples are output Processed samples are printed at the nominal processing rate The modulus words allow the user some control over data reporting 130 7546 001 Rev A 13 Specifications subject to change without notice aN 2 spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics rate All the enable disable words expect a true or false value on the stack to enable or disable the output The enable disable words are accel p Prints the raw accelerometer data The format is A 6d 6d 6d 6d r n with arguments timestamp x y x accelp p Prints the processes accelerometer data Format is AP d d d d F F F F F r n with arguments timestamp xraw yraw zraw xprocessed yprocessed zprocessed pitch roll gyro p GEDC 6 only Prints the raw gyro data Format is G 6d 6d 6d 6d r n with arguments temperature x y z DC 4 only Prints timestamp and temperature Format is G d 6d r n with arguments timestamp raw temperature coefficient gyrop p Prints the processed gyro data GEDC 6
23. VIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics 2 4 2 Comment lines NPL allows the use of bf as a comment that continues to the end of the line The traditional b and b pair may also be used Examples of comments b comment b traditional forth commentb 2 4 3 Expanded Data Types NPL allows entry of hexadecimal and binary numbers without changing base Hexadecimal numbers may be entered as OxDD binary numbers may be entered as ObDD regardless of the current number base of the interpreter Thirty two bit floating point values are supported Floating point values may be input starting with an F and must include a decimal point somewhere in the number Exponential notation is supported For example F1 0 F 2 5 F1 234E 6 and F123 4E5 are all valid floating point numbers Floating point numbers are always entered in base 10 regardless of the current number base A full floating point library is included as are input output routines 2 4 4 Strings during Interpret Mode Traditional Forth interpreters allow compile time strings with the and operators These create a string variable that the address of is provided when the compiled word is executed NPL allows the use of an interpret time string that is transient To
24. al store 0 in first position 1 storeCal 4 1 in the second postion therefore we are going to set array positions 0 1 storeCal 8 store the offset at position 2 in storeCal this is position 0 in the database array storeCal 12 store the divisor at position 3 in storeCal this is position 1 in the database array r start expects no argument It reads the current magFieldCalX value and stores it in the storeCal array for later restoration start stores the current cal magFieldCalX amp di get the pointer to magFieldCalX array dup duplicate the pointer read the first value swap 4 swap pointer for value advance and read second element in the array swap reverse the order so they are in correct order 130 7546 001 RevA 27 sn e spartom NAVIGATION AND EXPLORATION Specifications subject to change without notice The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics for the store word store store in the storeCal save array r create an alternate magFieldCalX array variable alternate 4 allot Initialize the array with desired values 0 alternate 1 alternate 4 10 0 alternate 8 0 5 alternate 12 This word is used to store the current field cal X Then
25. and Legacy Binary protocols 130 7546 001 RevA 12 aN Specifications subject to change without notice s S P a CUCO N NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics limits amp di Return the address of a data item The value is identical to di for arrays and strings For other types the address of the actual database item value is returned Can be used to read or set an item directly in real time Caution must be used to ensure that the type of the variable is known and correctly used This can be a pointer to Int32 or pointer to Byte so misuse of this pointer can be problematic set Expects an IDI then a value on the stack The value can be a single scalar an array using the array Jarray words or a string using the interpret mode string command See examples in the later sections for how to use this word If the variable is non volatile the NorthTek system will commit this variable to non volatile memory after a 5 second delay The delay allows multiple set commands to be executed in rapid succession and only one non volatile write to be performed for the combined set operations show Causes NPL to output the RFS Format message for this variable rec Set a variable with the same syntax as set however no non vol
26. any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics forget matrix Holding matrices for intermediate computations variable matrix 9 allot variable matrix2 9 allot matrix clear m This performs the actual computation compute form a matrix of the cp2 cpl and acceleration estimate cp2 di cpl di accelEst di matrix buildMatrix Transpose the matrix so the coefficients are in the columns matrix matrix2 T m Now take the inverse resultant matrix is the boresight matrix matrix2 matrix inv m matrix cr m This logic is a temporary array to copy rows from the result matrix into the 3 vectors that make up the boresight matrix the copy array variable copyarray 5 allot a word to compute array locations index 4 copyarray Copies a an array to the copy array after putting the 0 and 2 index bounds into the copy array cp 0 0 index 2 1 index dup 2 index 4 dup 3 index 4 4 index Use the copyarray and the cp function to put in each row of the boresight matrix from the computed matrix copyit matrix cp boresightMatrixX copyarray set note 3 4 moves up to the second row of a 3x3 matrix matrix 3 4 cp boresightMatrixY copyarray set note 6 4 moves up to the third row of a 3x3 matrix matrix 6 4 cp boresightMatrixZ copyarray set Print the resultant matrix and the new boresight matrix
27. appears inthis font Courier 11 Bold grey background Information that must be supplied by the user is enclosed in curly brace pairs The contents brace pair should be replaced with the user supplied data or will be filled in by the NavMod according to the description contained in the s The curly braces are not part of the transmitted characters Control sequences or other non printable characters are enclosed in lt gt pairs The following printable shorthand for some non printable characters is used e Acarriage return character is shown as lt CR gt or lt er gt e Aline feed character is shown as lt LF gt or lt 1f gt e Control sequences are indicated as lt CTRL S gt Other non printable characters are spelled out in lt gt pairs for example lt ESCAPE gt is equal to the escape character 0x1b The hexadecimal value will be used if needed for clarity Additional text will be included when the non printable characters might not be clear to the reader The blank or space character will be represented with 6 an overstrike b 130 7546 001 RevA 5 A Specifications subject to change without notice 1 S P a CCO N NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics 2 NorthTek Programming Language NorthTek Program
28. atile variables are immediately committed to non volatile memory This command can be used to try out new settings without committing to non volatile storage Note however that performing a set operation after a rec operation will write BOTH to non volatile memory Also the compass writes dynamically computed adjustments into the database on a periodic basis that are intended to be written to non volatile memory This will also cause any variables set with rec to also be written Contact Sparton Technical support should you need to use this command to fully understand the ramifications of using this command 4 2 General Database Operations In addition to the words that operate on individual IDI s other NPL words manipulate the database overall They are save Causes NorthTek to commit all non volatile variables to non volatile storage defaults Causes NorthTek to set all variables to factory default values wmm Print the world magnetic model data Not strictly part of the database 4 3 Streaming Sensor Data Operations NorthTek provides some controls to the real time compass engine These controls primarily control the printing of sensor data both raw and processed Because the raw sensor data is being continuously sampled it does not get written to the database Processed sensor data gets written to the database but is constantly overwritten as new values are computed To allow the user to capture the streaming data North
29. create a transient interpret time string simply start string with b and close with As with and there must be a space following the opening but not one before the closing At interpret time the operator creates a string up to 80 characters long in a temporary space and leaves the address on the stack The internal storage for the string is unmodified until another interpret time string is created or an interpret time array is created 2 4 5 Arrays NPL provides an interpret time temporary array of up to 16 elements The words array and Jarray are used to create a temporary array The syntax is array lower index upper index lowest element upper element Jarray Arrays are 0 based indices like other programming languages At interpret time the address of the array is left on the stack Note that the lower and upper indices are the first two elements in the array Both fixed and floating point values can be put into the array The array array pair can be used in a compilation During compile the operators create the same structure as the interpret time operators but the data is compiled into the word and thus is not transient like the interpret time version of the array that will be overwritten with the next array or interpret time string 2 4 6 Define Define all lower case in usage is a word that operates identically to constant in a traditional Forth constant is still available Define is both
30. cs variable turtleCount bump 0 0 lt if turtleCount 1 turtleCount else 0 turtleCount then turtle 0 turtleCount begin key 0 while read_z bump turtleCount 5 gt if Alert Upside down cr 7 7 7 emit emit emit send three alert characters bells then 1000 delay repeat 5 1 2 7 4 Criteria Limited Output This script illustrates an application where the compass value is only output if the heading varies by more than 10 degrees This would be useful in an application where the compass is remotely mounted and has a limited bandwidth channel in which to communicate or where multiple sensors must share a busy channel After downloading to run this program type filter lt CR gt To stop the execution press any key To unload this program type forget lastYawT lt CR gt Read the compass only output a value if the heading changes more than 10 degrees forget lastYawT variable lastYawT deviation make a copy compare to last value dup lastYawT f fabs 10 0 f gt compare absolute value of difference in last two readings to see if it is greater than 10 degrees if true store and output the value if dup lastYawT f cr make a copy store in lastYawt print value 7 7 7 emit emit emit send 3 alerts else drop drop the new sample change not big enough then filter first output the current heading yawt di dup f lastYawT 130 7546 001 RevA 26 A Specificatio
31. database item to its default value eee Set all values to default lve N ese IDI Increments the value of a scalar IDI that is on the stack show IDI Causes the compass to output the RFS Format message for the given variable dvid IDI v Return the internal RFS vid number for the given variable This will not match the external user VID number wmm Print the current world magnetic model wmmeeload as Force a World Magnetic Model to be loaded from EEPROM A 6NPL Logic These are logic commands Command Stack Diagram Notes ANSI Equivalent j v Pushes the outer loop index from a J nested do loop onto the stack i v Pushes the inner loop index onto the stack Compile Only repeat oa Closes a begin while repeat loop REPEAT while Forms the middle test of a begin WHILE while repeat loop Compile Only begin S Forms the top of a begin while BEGIN repeat loop Compile Only loop Closes a do loop structure Compile LOOP do S Opens a do loop structure Compile DO else Ca Begins the else clause of an if then ELSE else Compile Only then oe Closes an if then else structure THEN if Opens an if then else structure IF Take the token immediately but with whitespace remember and make a A 130 7546 001 Devons subject to change without notice 40 1e S P a CUO N NAVIGATION AND amp XPLORATION The content of this document is proprietary
32. dimensions This document is not designed to teach a non programmer how to program This section is merely a brief overview of NPL It is suggested that the user have the compass and terminal emulator handy and attempt some of the examples NPL Forth is an interactive language is typically best learned by experimenting 130 7546 001 RevA 6 Specifications subject to change without notice aN 2 spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics NPL is a stack based language and operates similar to an HP type calculator Any number that is entered is pushed on the operand stack Any arithmetic logical or binary operators operate on the items on the operand stack NPL does not use parenthesis instead it relies on postfix notation Postfix notation resolves operator precedence naturally In NPL the dot operator prints the top of the stack as an integer f does the same but prints as a floating point value Thus the following sequence first pushes two values then prints them NPL prints OK when it is ready for more input 1624 5 6251450K NPL is a simply parsed language The language is simply a series of tokens separated by white space In some cases primarily in string operations there is a slightly different rule tha
33. eers For Systems Engineers the manual serves as a capabilities overview This will assist in determining what custom functions may be implemented in NorthTek to aid in system partitioning For Software Developers this manual serves as the reference for developing NorthTek applications This manual is roughly organized into the following areas e Basic NorthTek Programming This is the basics of a programming language and environment e NorthTek System Environment This describes the execution environment of NorthTek as to how and when programs get loaded and executed e Sensor Data Base Interface This describes how the NorthTek language and environment interact with the sensor real time computation engine e Application Examples Sample applications that tie the other sections together 130 7546 001 RevA 4 Specifications subject to change without notice aN e spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics 1 4 Preparations for using NorthTek As already discussed this manual is primarily directed at Software Developers As such this is not a primer on programming The expectation is that the user is already fluent in one or more programming languages and is familiar with the real time software operating paradigm Th
34. engine the Forth programming language and Technical capability with a bit of poetic license taken with spelling NorthTek allows an application or integration engineer the ability to tailor a NorthTek equipped sensor to the operating environment of a product even in real time as conditions change with the device in which it is incorporated This gives the user the ability to solve attitude and heading reference problems that previously could not be solved or could only be solved with expensive or difficult to develop solutions 1 2 How is NorthTek Used NorthTek is used by downloading a program into the sensor and having that program implement custom algorithms in the sensor with tightly coupled access to the sensing environment That program then allows the sensor output to be both correct and timely for the application environment This paradigm breaks the normal sensor paradigm where the sensor merely streams raw data and it is up to the integration system to filter and process the raw data to extract the needed information NorthTek can be used for example to limit the sensor output to only specific conditions which may be of interest to the system or to switch from one set of operating parameters or calibration to another based on changing conditions This capability does not exist in the traditional streaming sensor paradigm 1 3 Organization and Purpose of this Manual This manual is intended to be used by Software Developers and Systems Engin
35. er needs with no ill effects on the compass A future feature will allow a NPL program to be permanently stored in the compass and automatically executed at power up or upon recovery from low power mode Currently all user programs are volatile and lost once the compass has been powered down or put into low power mode Once a program is loaded the commands can be executed by simply sending the text string containing the command name 130 7546 001 RevA 11 Specifications subject to change without notice aN e spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics 4 NorthTek Database and Compute Engine Interface A Sparton NavMod contains an embedded database This database contains both the calibration configuration and sensor readings in a unified structure Some of the data items are transient and do not survive a power cycle compass heading is one example Some of the data items are non volatile in that when set they will be the same after a power cycle baud rate is one example On a different axis some of the non volatile items are only settable at the factory The user can set the value temporarily but the factory set value will be recovered after a power cycle or low power cycle Some values are read only such as the device name
36. ew this section and recall that all input must be either a word or a number surrounded by white space an Adding a new word to the dictionary is straightforward The word colon indicates that the user an wishes to define a new word What follows the is the name of the new word The name must not an include any embedded white space As an immediate reminder to the preceding section the must be surrounded by white space A common mistake is to run the and the name of the word together without white space Thus imynewword will cause NPL to emit an annoying HUH because there is no word in the dictionary called smynewword To make our previous example into a word the user would type myword1 2 The terminates the definition of a new word The user can then type words to see that myword has been added to the dictionary Note that to be successful all the tokens must be surrounded by white space including the and the The user may execute the new word by entering myword to which NorthTek will output 2 1 OK The NPL stack is the mechanism by which arithmetic is performed and parameters are passed The use of the stack is illustrated in the following examples These examples utilize one of the fundamental control structures in NPL the do loop The syntax is straight forward two values are pushed on the Because smyword and are
37. h is to be expected Since is a command whitespace must follow it so the basic NPL parser can identify it but once is executing it looks ahead in the input buffer for a closing mark Whitespace is not needed before the closing mark since is doing its own parsing instead of the normal NPL parser So by example to print the classic Hello World in a forth macro the syntax is bHello World bcr 130 7546 001 RevA 22 Specifications subject to change without notice sn e spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics In this example whitespace is represented by the literal b character The er at the end of the line prints a carriage return 5 1 2 6 Dealing with Arrays NPL allows setting of arrays The syntax is arrayVariable array starting index ending index Vstarting Vs 1 Vending jJarray set 5 1 2 7 Advanced Applications This section describes several advanced applications To run these programs 1 Copy the text below to a plain text editor i e Notepad do NOT use Word etc 2 Save the file to some known location on the computer 3 Start a terminal program such as Hyperterminal or TeraTerm TeraTerm is recommended if technical support is needed 4 Configure the
38. he user may execute the word status to see how much of the free dictionary space remains The dictionary may be pruned with a word called forget Forget releases all the words in the dictionary from the end back to the word passed to forget If the user has been following with the examples the dictionary will now include the words myword count countFrom0 and countFromMtoN The user can clean up the dictionary be executing forget myword This is important when learning NPL to avoid a runtime error caused by exceeding the allowable dictionary space 2 3 Standard NPL Words The NPL dictionary is described in one of the appendices Where there is a corresponding ANSI Forth word it is listed as a cross reference and the user can expect the behavior to be as described in the ANSI Forth standard The Cell size for NPL is 4 bytes The word size used by w and w is 16 bits 2 4 ANSI Forth Differences NPL has like many Forth implementations its own minor differences Some of these differences are minor and will be dealt with on a case by case basis Some of the more significant differences will be described in this section 2 4 1 Case NPL like most Forth interpreters is case sensitive In NPL all language primitives are in lower case thus constructs like do if and then are as written here 130 7546 001 RevA 9 Specifications subject to change without notice sn e spartom NA
39. htly non standard The syntax is if true stuff else false stuff then continue on with other stuff The if tests if the top of the stack TOS is non zero for true Thus the following simple example test if true else false then cr execute it 1 test lt cr gt true OK 0 test lt cr gt false OK Enough said 5 1 2 1 4 do loop The do loop is straight forward do expects two values on the top of the stack the starting index and the terminal count The loop executes over starting value to terminal count 1 Thus the following example prints the integers from 0 to 9 Note that the command i returns the current loop index The second example shows a nested loop and how to access the index of the outer loop count do i loop execute it 10 0 count lt cr gt 0123456789 OK nested do i 0 do i j loop cr loop execute it 5 0 nested Blank line printed here 01 0212 031323 04142434 OK 5 1215 begin while repeat The begin while repeat structure implements either a top tested loop while or a bottom tested loop until simply by placing the while command at the appropriate place in the loop The syntax is begin stuff that is always done while stuff that is done if the condition at while is true repeat The little 130 7546 001 Rev A 17 Specifications subject to change without notice aN e spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No
40. iage return newline or a space character Tab characters are not used in NPL 130 7546 001 Rev A 7 IN 18 spartom NAVIGATION AND EXPLORATION Specifications subject to change without notice The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics token that is parsed at compile time it is a command that is executed at runtime and must be surrounded by white space both before and after For example the following statements 7 comment 7b comment 7 ecomment While appearing to be legal and would in fact be legal in C these statements cause NPL to emit HUH indicating that the token cannot be found in the dictionary or made into a number This is because the first statement has only one token 7 comment that is neither word nor number The second statement has two tokens 7 a valid token and the token comment that is neither word nor number The third statement has two tokens 7 and comment neither of which are valid tokens The correct syntax for NPL would be 7b bcomment For the remainder of this document the b symbol will be omitted unless it is particularly helpful or important to enhance readability Should the reader encounter difficulty with commands that appear as though they should be working the reader should revi
41. ions subject to change without notice OU S P a CUCO N NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics 0 inverts so then while while tests for no key pressed magErr di print the mag error 250 delay wait 250 msecs to print again repeat end of begin while repeat Calibration done cr celllll e braaaate good times come on calCommand cal_end set cal computation calmode 0 set terminate but I ll be back end of compiliation To execute the calibration simply type cal3D Or uncomment the line above and the script will run when it is loaded To unload this program type forget cal3D 5 1 2 4 Don t Forget forget The memory space for new NPL words is unfortunately not unlimited As a user begins to experiment with writing NPL words the wordlist will fill up enter the status command to see how full Fortunately there is a way to forget all the words that have been defined by the user The command forget followed by a word will erase all defined words back to and including the named word in the wordlist think reverse linked list model you cannot forget words that are defined before you start your definitions 5 1 2 5 Four More Special Words There are a few
42. is manual is written assuming that basic programming ideas such as variables loops function etc do not need further explanation The user is encouraged to download one of the many PC based Forth interpreters and practice on Forth programming Sparton can provide a PC based Forth interpreter that closely matches the NorthTek Programming Language NPL interpreter 1 5 References Some documents and online references will be helpful to the reader in learning to program applications in NorthTek Namely e Starting Forth Leo Brodie Available online at http www forth com starting forth e Thinking Forth Leo Brodie Available online at http voxel dl sourceforge net project thinking forth reprint rel 1 0 thinking forth pdf e ANSI Forth Standard ANSI X3 215 1994 e Other references may be found here http www mpeforth com books htm e Remote Function Select RFS Interface Design Description e Sparton Navigation Modules Software Interface User s Manual 1 6 Document Conventions Typographic conventions are used in this document to highlight items that may be typed or transmitted to the sensor or output from the sensor The sensor will be referred to as sensor Navigation Module NavMod device or compass interchangeably in this document Descriptive text in this document appears in this font Calibri 11 Data transmitted to the NavMod appears in this font Courier 11 Bold Italic Data sent from the NavMod
43. ltiple commands to be collated into one single non volatile write operation Expects an internal database identifier on the stack followed by a value Sets the item to the value given See advanced programming section on how to handle arrays See the Software Interface Users Manual applicable to the product being used for the list and details of variables that may be set The result is O if the set did not complete properly for example if the value was out of range If the set operation completed properly the return value will be not equal to 0 Does not cause the non volatile items to be written However the compass periodically writes updated calibration to non volatile memory and would include values set by rec in that process Expects an internal database identifier on the stack prints the current value Returns the value of a an IDI scalar or a pointer to 39 Oy spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics and IDI string or array amp di IDI address Returns the address of the data for the given variable di gt IDI Causes the compass to output the RFS Get_Value message for the given variable save Co Save any changed variables to non volatile memory gt default IDI Set the
44. ming Language NPL is a slightly modified Forth programming language NPL does not strictly adhere to the ANSI standard due to its embedded nature however the intention is for it to be familiar to someone already proficient in Forth programming and environments The core language is largely ANSI compliant There are many references available in print or online for learning to program Forth An experienced programmer will likely review one of the various references and pick the language up quite quickly The appendix provides a listing of the words in the dictionary along with the ANSI equivalent word This section provides some of the basic concepts of NPL and includes some of the major differences between NPL and ANSI Forth 2 4 Environment The NorthTek environment is a simplified model The compass provides a command line user interface on the serial port The user connects to the compass with a simple terminal emulator such as TeraTerm or Hyperterminal The user can type commands by hand or send the commands as files using the simple file transfer facilities built into these terminal emulators Note that NorthTek is an interpreter that is running as a low priority task in a multitasking real time environment in a resource limited microcontroller To give the interpreter time to process each line of text a small amount of timing delay 5 msec must be added to each line of a file transfer for baud rates above 38 4k In TeraTerm this option is available
45. n v1 placing the result in vr Builds a matrix from v1 v2 and v3 Each vector forms the rows of matrix m Generate rotation matrix mr from vector v1 and angle theta Multiply matrix by vector place result in vector Multiply matrix m by vector v1 place result in vector vr Multiply float value by each element of v2 place result in vector vr 4 element vectors Multiply float value by each element of matrix m putting result in matrix mr Copy vector v1 to vector v2 4 elements 35 Oy spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics y y vl v2 TIF Returns true if the two vectors are equal 4 elements m gt m ml m2 Copies matrix m1 to matrix m2 T m mmr o Transpose matrix m place result in matrix mr clear v ee Makes all 4 elements in vector v 0 0 vtv gt r vl v2 vr Add vector v1 to vector v2 place result in vector vr v v gt r vl v2 vr Subtract vector v2 from vector v1 place result in vector vr lv v m Compute the magnitude of vector v return the value on the top of the stack v 3 lv v Compute the magnitude of vector v placing the result in the an index 4 position Ix y xy v Compute the 2d magnitude of the two element vector created by x and y re
46. ns subject to change without notice s S P a CCO N NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics begin key 0 while yawt di deviation read the current yaw send to function 500 delay repeat 5270 Real Time Field Calibration Swap This application example shows how to modify the compass operation in real time In this case the magFieldCalX value is being changed according to an operational mode in the host device The hard coded numbers represent an alternate calibration value obtained during system setup If the end user has a need for this type of operation please contact Sparton Technical Support for programming application assistance for this type of problem The inline comments can be examined for how this program operates change field calibration on the fly forget storeCal this unloads a previous version of the program if it is being re downloaded create a variable to store the current calibration 4 elements so it is an array variable storeCal 4 allot This stack diagram indicates that the divisor and offset are on the stack before calling this word divisor offset This word formats the storeCal array to be compatable with the set database word store 0 storeC
47. nvsbncewdsva vad eblscndaavevescdentece 33 A 1 NPL Arithmetic and Logical sitscaccccasccssceeaccg cessteseteencbeiwes ea a aaa iE eE 33 A 2 NPL Parameter Stack Manipulation cccccsscccsssssececeenececeeeeceeseaeeeeseaeceseeaaeeeeeeaaeeeeseaeeeeeeaaes 36 A3 NPLINpUt OUtp Utes ser ccet ect anina aeaa aaiae aa Ea Geen Hoehne ane 37 A 4 NPL Variables Constants sivstesdaccc vessestes candies vevstagetedacccues a i aaa E E 38 A 5 NPL Database a ns sce accd facet on estes Sock e aee Ae a are chasers aee ea AE a E EE EEE 39 A 6 NPLLOBIC onenetan e EE EEEE Ee EEE R EE EE RE 40 130 7546 001 Rev A 3 aN e spartom NAVIGATION AND EXPLORATION Specifications subject to change without notice The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics 1 Introduction 1 1 What is NorthTek NorthTek is a problem solving system for navigation sensors NorthTek is the combination of a programming language a compiler an interactive command line interpreter a database and a real time computation engine The compiler interpreter execution environment provides an interface into both the database and the compute engine The combination of all these elements is the NorthTek Programming System The name NorthTek came from the underlying components of the system namely a Navigation
48. of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics 3 Engineering Pacheesi cr 4 Sales Poker cr 5 Investment Roulette cr 6 Global Thermonuclear war cr r these words emit the VT100 terminal escape sequences Consult a VT100 terminal document for details home outputs lt ESC gt 2J lt ESC gt H i e clear screen and home 27 emit 2J 27 emit H red outputs VT100 sequence for red lt ESC gt 5 30 41m 27 emit 5 30 41m black VT100 for black lt ESC gt Om 27 emit 0Om W _ W cr Gf W cr 1 1 I ttt ttt tot tt er _ cr bomb 25 0 do cr 100 delay loop boom r game dup char 1 literal if note allows interpret mode Too much drinking cr else dup char 2 literal if Too depressing cr else dup char 3 literal if 130 7546 001 Rev A 24 Specifications subject to change without notice aN e spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics Too boring cr else dup char 4 literal Too Risky cr else dup char 5 literal
49. oncepts for example this is a good reference http www forth com starting forth Each command is shown with a stack diagram that shows the state of the parameter stack before and after the command The syntax of the diagram is before after with the top of the stack shown on the right hand side of each before or after set It is usual practice to have white space around the parenthesis so that the stack diagram forms a comment A 1NPL Arithmetic and Logical NPL contains a full set of arithmetic and logical operators for both fixed and floating point 32 bit values Each command is described briefly below A 1 1 Integer Commands Command Stack Diagram Notes ANSI Equivalent a b a b Divide the second stack item by the item on the top of the stack s ab a b Signed divide of the top to items on the stack a b a b Multiply the top two stack items s a b a b Signed multiply of the top two items 7 E a b a b Subtract the top stack item from the next item up on the stack a b atb Add the top two stack items gt gt a b a gt gt b Shiftthe 1 deep stack item to the right RSHIFT by the number of bits specified by the value on the TOS lt lt a b ax lt b Shift the 1 deep stack item to the left LSHIFT by the number of bits specified by the value on the TOS mod a b a b Leave the remainder after division MOD modulus mod ab a b Leave the quotient and
50. or shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics top of the stack and puts in on the stack ce value addr Stores the 8 bit value that is 1 deep in the C stack at the location that is on the top of the stack Stores the 32 bit value that is 1 deep in the value addr stack at the location that is on the top of the stack e addr value Reads the 32 bit value at the address on the top of the stack and puts in on the stack A 5NPL Database These are database commands Command Stack Diagram Notes set IDI value result rec IDI value result di IDI di IDE v 130 7546 00 1 Rev F KRYA subject to change without notice Expects an internal database identifier on the stack followed by a value Sets the item to the value given See advanced programming section on how to handle arrays See the Software Interface Users Manual applicable to the product being used for the list and details of variables that may be set The result is O if the set did not complete properly for example if the value was out of range If the set operation completed properly the return value will be not equal to 0 If the value set is non volatile causes the non volatile variables to be written back to non volatile memory Note that there is a 5 second delay before variables are written to allow mu
51. ot possible e You can work in any number base up to 37 The base variable contains the current number base for i o Decimal and hex put in the two standards Decimal is defined as decimal 10 base hexisdefinedas hex 16 base Soyou can use whatever base you want Binary is helpful You can get the current number base with base Remember that s prints the stack but always in decimal and hex so this is a good sanity check when playing around in the number base So to work in binary do 2 base Note that the word decimal is necessary because once you are in base 2 10 base does not return you to decimal it puts you in base 10 which is 2 to accomplish this you would have to do 1010 base This is why decimal exists By example hex aa 2 base prints 10101010 130 7546 001 Rev A 30 Specifications subject to change without notice aN 2 spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics e The status word tells you how much NPL memory you are using If you are doing something exotic run that once in a while and if you are overflowing the memory funny things might be happening e The begin key 0 while stuff repeat construct is your friend It makes a loop till you hit any key
52. ponsibility of the user to do the correct scaling of pointers to get to the correct addresses This is identical to the standard Forth language and any quick internet Forth tutorial will provide many examples Some simple examples follow variable x create 32 bit value x x read and print x 1234 x store 1234 in x 5678 x x store 5678 in x read it and print it create a buffer that is 10 32bit values variable creates one allot adds 9 more not initialized variable buffer 9 allot create a word to index the array for read expects an index on the top of the stack followed by variable location v 4 130 7546 001 RevA 18 A Specifications subject to change without notice s S P a CCO N NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics does the store operation expects value variable index v 4 buffer 0 v print the Oth element 1234 buffer 7 v store 1234 in the 7th element 5 1 2 2 Common Compass User Commands The table of NPL commands Appendix A NPL Command Categories is at first overwhelming However like any complex system the user generally uses only a small percentage of available commands This section describes the most common NPL commands that an
53. ration These are commands to declare and manipulate constants and variables Command Stack Diagram Notes ANSI Equivalent constant variable allot w w c value value addr addr value addr value Reads the token just past constant and CONSTANT makes a constant with that name and the value found on the stack For example 1234 constant myValue Creates a constant whose value is 1234 Creates a 32 bit variable initialized to 0 VARIABLE using the name that follows the word variable When the variable name is executed it returns the address of the variable Allocate the number of 32 bit words to the ALLOT variable just allocated For example variable buffer 3 allot creates a 4 element array called buffer When buffer is executed it returns the address of the first element The values are NOT initialized to 0 Stores the 16 bit value that is 1 deep in the stack at the location that is on the top of the stack Reads the 16 bit value at the address on the top of the stack and puts in on the stack Reads the 8 bit value at the address on the c 7 ANSI ALLOT allocates bytes but the function is the same NPL allocates in 32 bit chunks 130 7546 09 1 Rev s KRYA subject to change without notice 38 TO spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced n
54. rdlists produces a lot of output The compasses have a lot of variables and it may sometimes be difficult to locate the correct variable Grep grep as typed is available to search for words with only a substring The syntax is grep substring The substring and target are compared in a case sensitive way Thus if the word that is being searched for is thislsTheVariable and the user believes that isthe is part of the variable the search substring must be IsThe 3 NorthTek Application Environment NorthTek is a user interface process executing on the compass It is running at a low priority in the system so that it does not interfere with the real time calculations that are being performed to compute the attitude and heading of the compass NorthTek via an NPL program is used to monitor the heading change the way the heading is computed or control the output of the heading information to the user NorthTek has the ability to cause other compass protocols to be transmitted e g RFS messages NorthTek has the ability to modify the calibration in field calibration or boresight matrix in real time to adjust to changing conditions on the host device NPL programs are loaded onto the compass by simply transmitting the text file to the compass after power up Multiple programs may be loaded as long as the dictionary space is not exceeded Programs may be loaded executed and removed using the forget command as many times as the us
55. remainder on MOD se the stack as the result of an integer division xor a b a b Exclusive or the top two stack items XOR not a a Take the ones complement of the item NOT A 130 7546 00 33 ie Spartom NAVIGATION AND EXPLORATION 1 Rev F KRYA subject to change without notice The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics on the top of the stack or a b alb Bitwise or the top two stack items OR and a b a amp b Bitwise and the top two stack items AND v addr Add the value 1 deep in the stack to the value stored at the address on top of the stack Can be used to increment decrement variables easily abs a abs a Take the absolute value of the top of ABS the stack gt ab T F Compare the top two items return true gt if the 2nd item is greater than the 1st item else return false lt ab TIF Compare the top two items return true lt if the 2nd item is less than the 1st item else false negate a a Take the two s complement of the top NEGATE of the stack 0 v TIF Compare the top of the stack to 0 and 0 if so return true else return false 0 gt v TIF Return true if the item on the top of 0 gt the stack is greater than 0 0 lt v TIF Return true if the item on the
56. replace it with the alternate on start magFieldCalX alternate set drop note drop is required because set returns a T F success value LA This word restores the magfield cal to the original value off magFieldCalX storeCal set drop r This word is used to restore the original field to some know values in case of an operator mistake restore F24 1458 1 079998 swap store magFieldCalX storeCal set r Program that prints out the heading until a key is pressed The user should type on or off then heading to see the effect of the two different field calibrations hdg begin key 0 while yawt di 500 delay repeat r 5 1 2 7 6 TARE Command This program allows the compass to be mounted in any configuration within the host device and then adjusted so that the roll pitch and yaw outputs are aligned with the device not the compass This allows totally arbitrary placement of the compass in the host device All that is required is to position the compass in the desired position then send this script wait until the OK prompt is returned as the script takes 5 seconds to run then wait 5 seconds for the database to be stored then reset the device TARE function 130 7546 001 Rev A 28 Specifications subject to change without notice IN 2 spartom NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall
57. rt of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics 5 NorthTek Programming Examples 5 1 1 Simple NPL examples At this point a few detailed examples may be helpful 5 1 1 1 Print Compass Heading Example This example reads the current compass heading yaw di lt CR gt NPL prints yaw 4 433077e 01 OK 5 1 1 2 Setting the baud rate This example shows how a variable may be set to implement a configuration change In this case the user is going to change the baud rate The user should inspect the baud database parameter and values in the appropriate device user manual In this case the baud rate index 4 is 9600 baud and baud rate index 8 is 115200 baud Assuming the NavMod is already operating at 115200 the user enters baud 4 set lt CR gt The serial port on the user s terminal needs to be changed to 9600 at this point Commands may now be entered at 9600 baud The user can return to 115200 by entering the command that follows and then changing the user s terminal baud rate back to 115200 baud 8 set lt CR gt 5 1 1 3 Print Acceleration Example This example shows how an array is printed In this case the raw and processed acceleration value accelr di lt CR gt accelr 00 2 080000e 02 01 9 760000e 02 02 1 408000e 04 OK accelp di lt CR gt accelp 00 1 660156e 01 01 2 832031e 01 02 1
58. scccessssceceesssceeecsseseceeseseceesessececsesecsesseseeecseeseesesseaeees 5 1 5 ReEferGnCes iaia e E E EE E a E a ER 5 1 6 Document CONVENTIONS aosrerrasiiirr ornar eaa r EEO E E RO OA ETEO 5 2 NorthTek Programming Language cccc ccccssisscdesdecaidecsssactengesniacssetscdeevacsidessttcdeudesticdepsencbeddacniaeeseensades 6 2 1 AATE D E E E EA E A E E A A E E 6 2 2 NPL BASICS iucruciis Stan E T E E 6 2 3 Standardi NRE W OFS its ctsteresacocsese stetesi sa oeaiei aran a Eaa a a EA R ETa S EREE AEE EAEE OE 9 ZA ANSI Forth DiIMEreNCeS viseira AEEA EAEE AE AEEA 9 3 NorthTek Application Environment ccccccsssscceceeeesssesseaececececesseeaeaeseeecesessesaeaesececeseesnasaeseeseeseesega 11 4 NorthTek Database and Compute Engine Interface ccccscccssscssssecesececseeessaecssseecseeessaeesssaeesenees 12 4 1 Internal Database Identifier Operations ccccscessssseceeseeececseeaeceeseaaececseaaeceseeaaeeesseaeeeeeeaaes 12 4 2 General Database Operation vviivscciseicacedeieteevsusecd vustescedees ted savecncaevewstcd vvedveaedevsecd sdbecetagysudedd sweets 13 4 3 Streaming Sensor Data Operations ccccccceceeeeeeeennecececeeeeeeeaaeceeeeeeeseeaaaaeceeeeeeeeeeaaaaeeeeeeeeeeaaaa 13 5 NorthTek Programming Examples cccccseessssscecececeesesneaeceeeceseeseaeaeceeecssessesaeaeseeeceseeseaeaeeeeseeseeseea 15 A NPL Command Categories sias ccsiececiecteccudivs ued cobecwcanvsuctsdesuedebeneseaeadesivanccaiisvssede
59. so the binary number 1 after converting the string 1 toa numeric value is pushed on the stack The next token 2 is handled in the same manner thus pushing 2 onto the operand stack The third token is found in the dictionary and is thus immediately executed causing the top item on the operand stack to be destructively printed The last token is handled in the same way causing 1 to be printed Finally the end of the input line is reaches and NPL prints OK to indicate that it is ready to interpret some more commands There are a few points of confusion for programmers in traditional languages In traditional languages there are tokens called delimiters For example in C the semi colon is a delimiter and is used to terminate a command For example x 7 is a valid C statement and is equivalent to x 7 xb b umn 7b5 C does not care if there is white space between the 7 and the nor does it care if there is un space surrounding NPL is different in that is a command itself and not syntactical padding thus it must be surrounded by white space This is especially confusing for beginners when dealing with comments In NPL makes the remainder of a line a comment However it is not a pre processor 1 HP refers to Hewlett Packerd Company and is a registered trademark of the same No claims are made to any HP technology White space is either a carr
60. so you can design your own message content so everything comes in one message e With NPL you can shorthand anything quickly If a variable is someVeryLongNameThatsAPainToType and you plan on working with the variable for a while you can quickly type it someVeryLongNameThatsAPainToType and then use it whenever you want the long thing e Take note of the first few lines of each sample application Note that each contains a line that forgets the first definition in the application This is present so that when the application is reloaded over and over during test it automatically cleans out the previous instance of the application On the first load the first definition is not found so NPL prints can t find it but this is harmless This is good practice and keeps from overflowing the dictionary space e The NPL operand stack is of finite depth It is sufficiently deep for virtually all applications however it can be overflowed quickly in a loop for example Take care to keep the stack size small lt 32 items The s operator prints the stack contents Note that the set and rec words return a flag indicating success or failure A common mistake is to forget to drop the result if there is no plan to test it This often leads to a stack overflow and a lockup of the interpreter and or compass e The NPL interpreter operates in a virtual memory space access to flash memory or hardware peripherals is n
61. string declared this way overwrites the previous one same way with string The arrays need to be small lt 16 elements strings lt 80 characters They use the same temporary space so you can only have one at a time lying around The words array and J array can be used in a compiled word For compiled words closed with creates a compile time string e The set word automatically determines the variable type from the variable identifier It is up to you to make sure to provide the correct data The syntax is variableName value set The value is an integer for integers and ordinals a float contains F and for floats A string string for strings and the array syntax for arrays So for example to set a 3 element array call bob bob array 0 2 v1 v2 v3 array set pushes the variable info uses the interactive array function to create an array with the values 0 2 v1 v2 and v3 and passes this array to set Set expects the first two array elements to be the starting and ending index of the values in the array you want to set The remaining part of the array is the values to set with e You can crash the software with NPL it is not Java after all so if you are playing around you might need to have access to the power switch on your device If you stick to the mainline commands that typical users are using everything will be ok but if you attempt to divide by 0 index way beyond the end of an array access memory that
62. t is explained in the formal language description in the references the rule is relaxed however for beginning purposes all tokens are separated by white space There are no rules about how many tokens can appear on an input line or if control structures may span multiple lines A token is a series of printable alphanumeric characters that contains no spaces The NPL interpreter is composed of a set of individual commands called words One individual NPL command is called a word All of the NPL words are grouped together logically into lists called wordlists The word words will cause NPL to print out all the words in all the wordlists in reverse definition order The wordlists are arranged in a reverse chronological order The combination of all wordlists is called the dictionary When a new word is created is said to be defined Each new word that is defined is added to the end of the last wordlist the first one displayed when words is entered Tokens are either words in one of the wordlists or numbers This bears repeating for emphasis All tokens are either words i e commands in the dictionary or numbers in the current number base In the example above the input line that was typed was 1 2 lt cr gt NPL s interpretation of this line is to first find the first token 1 and see if it is a word in the dictionary Not finding it NPL attempts to make a number out of 1 and is successful
63. top of 0 lt the stack is less than 0 ab TIF Compare the top two stack items and 7 return true if they are equal else return false A 1 2 Floating Point Commands Command Stack Diagram Notes ANSI Equivalent pi 3 14159 pi d gt r fd fr degrees to radians r gt d fr fd radians to degrees exp E e computes e FEXP log log x computes log x floor floor f floating point floor function FLOOR ceil f ceil f floating point ceiling function pow fa fb fa computes x atan atan f arc tangent radians FATAN acos acos f arc cosine radians FACOS asin asin f arc sine radians FASIN tan tan f tangent radians FTAN cos cos f cosine radians FCOS sin sin f sine radians FSIN fround round f round floating point number FROUND ftrunc trunc f truncate a floating point number f gt i f i convert floating point to signed 130 7546 0091 Rev A p RENTEN 34 NO spartom Sp citications subject to change without notice CW NAVIGATION AND EXPLORATION 130 7546 00 The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein i gt f fabs a fx f f gt f lt f lt f gt dot dot3d Cross v v gt v neq norm norm4d buildMatrix genRotMatrix m
64. ts the item to the factory default value Note that if the value is non volatile it will not be stored in permanent storage unless save is performed on the database di Gets an objects value For Int32 s ordinals fixed and floating point values the value returned is the actual value For arrays the value returned is the address of the first element For strings the value returned is the address of the count byte di gt Forces the compass to output the value of the variable in RFS protocol with a binary Value_Is message di Returns true or false as to whether or not the variable value is within range Note that a properly written host application can accept NPL commands and RFS messages at the same time Since NPL uses all printable characters with the exception of carriage returns a front end multiplexer can parse for the SOH character that starts an RFS message and send all intervening characters to the RFS processor up until the ETX All characters received outside the SOH ETX pair can be passed to the user terminal Thus an NPL program can provide human readable output and interaction while RFS output is being supplied either on demand or continuously On the output side the host application must only ensure that the printable NPL output is not allowed between a SOH and ETX as the compass will interpret this as part of an RFS packet This is in fact the algorithm used by the compass to simultaneously accept RFS NMEA NPL
65. turn the resut on the top of the stack clear m m Set all matrix element equal to 0 0 m 1 m Set matrix m equal to the identity matrix m m gt r ml m2 mr Multiply matrix m1 by matrix m2 place the result in matrix mr inv m mmr Compute the inverse of matrix m place the results in matric mr m m Print matrix m in free format m f wfm Print matrix m in w f format Va v Print vector v in free format v f wfv Print vector v in w f format A 2NPL Parameter Stack Manipulation These commands allow manipulation of the parameter stack Command Stack Diagram Notes ANSI Equivalent drop tne Drops the top item from the stack DROP s Prints the stack contents non S destructively pick v vth item Copy the vth item in the stack to the PICK top of the stack 2drop vl v2 Drop the top two items from the 2DROP stack nip vl v2 v3 vl v3 Removes the 2 item down in the NIP stack 2dup vl v2 vl v2 vl v2 Duplicates the top two items on the 2DUP A 130 7546 09 36 en SPartom NAVIGATION AND EXPLORATION J V4 1 Rev F s teens subject to change without notice The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein over dup vl vi vl swap vl v2 v2 v1 rot vl v2 v3 v2 v3 v1 A 3NPL Input Output be made without written authorization from
66. uted Quaternions 1 quat p enables print of computed quaternions Output format is QUAT f f f f 130 7546 001 Rev A 20 A iy Spa CECOM Specifications subject to change without notice NAVIGATION AND EXPLORATION The content of this document is proprietary No part of this document shall be reproduced nor shall any use or disclosure of the information contained herein be made without written authorization from Sparton Electronics quaternion vector w x y z respectively 0 quat p disables 5 1 2 3 3D Compass Calibration This script performs 3D compass calibration To perform calibration use a dumb terminal to send this to the NavMod if you see huh flying by add some delay to each line transmitted or reduce the baud to 38400 Once the script has been loaded send the command cal3D The script will then prompt the user to capture calibration points The user should move the compass around and select between 4 and 12 points then hit ESC The script will then print the magnetic error at a 0 5 Hz rate Observe the magnetic error until it converges sufficiently then hit the spacebar or any other key The compass will now be field calibrated The cal3D command may be re entered as many times as desired without re loading the macro The macro needs to be loaded only once while the NavMod remains powered up There is enough information in the basic programming section and the appendix to analyze this macro sufficientl
67. y should the user desire to extend this functionality to other custom user scripts cal3D start compiling a new word called cal3D calmode 1 set set the calibration mode to 3D Calibration starting cr tell the user we are starting then lt CR gt calCommand cal start set issue the cal_start command Press any key to take next point ESC to finish cr Tell the user what to do The code now grabs a point the user changes the compass position and repeats the cal3DState from 4 12 times total begin begin a begin while repeat loop key 27 0 wait for key input compare with ESC invert the logic 0s while only continue if the TOS has a true i e user hit a key ESC calCommand cal capture set take another point 250 delay wait 250 msecs to allow point to be counted calNumPoints di print out point number repeat end of begin while repeat Now the points are captured command the SW to compute the cal values calCommand cal _ end capture set issue command to end the capture of points Starting error settling cr tell user what s going on Press any key to terminate cr issue instructions The user observes magErr to watch it settle at a minimum value EKit can display every sec or so begin keep printing magErr at 250 sec intervals key 0 key returns false hit a key is hit 130 7546 001 RevA 21 ON Specificat

NorthTek

Contents

Download Pdf Manuals

Related Search

Related Contents