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cambasic - Remote Processing

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1. PURPOSE REMARKS RELATED EXAMPLE ERROR n LEFTS m p To return the leftmost p characters of m LEFTS String Function If p is greater than the length of m the entire string m will be returned If p 0 a null string is returned LEN MID RIGHT INSTR 10 A Hopeless 20 B LEFTS AS 4 30 PRINT BS RUN Hope lt Datanegative gt forp lt Data gt 255 gt forp Commands 68 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR n LEN m To return the number of characters in m Unprintable and blank characters are counted LEFT MID RIGHTS INSTR 10 A Short string 20 PRINT LEN AS RUN 12 none Commands 69 LEN Numeric Function SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR LINE Process Function a LINE terminal To return the status of an input on a STB 26 terminal board The terminal has a one to one correspondence with the terminals on the STB 26 terminal board This feature eases documentation and troubleshooting Refer to Card Manual for terminal number range A 1 isreturned when a line is logic high 0 when logic low The LINE function is similar to the BIT function in that individual I O bits or channels can be read It differs in that it is used specifically with the STB 26 terminal boards and it executes much faster LINE statement 10 OUT 0 1 20 PRINT LINE 119 RUN 1 In thi
2. 11000111 This example illustrates the usefulness of BIN to determine the status of an I O port Suppose that the port is connected to switches Reading the value with the INP function yields 199 Without doing calculations it is difficult to tell which switches are on Using BIN you can see immediately that switches 0 1 2 6 and 7 are on lt Type mismatch gt ifm isa string or n is not a string lt Data gt 255 gt form lt Data negative gt form Commands 10 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR n BIT O address bit To read a specified bit at a specified I O address This function returns a 1 if the bit is high anda 0 if it is low This function will operate only with I O addresses not memory addresses BIT statement INP ON BIT OUT 10 OUT amp 10 209 15 FOR X 0 TO 7 20 PRINT BIT amp 10 X 30 NEXT PRINT RUN lt Data negative gt for J O address bit lt Data out of range gt if bit gt 7 lt Data gt 65 535 gt for O address Commands 11 BIT Process Function SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR BIT Process Statement BIT VO address bit value BIT TO address bit ON BIT TO address bit OFF BIT VO address bit NOT To set or turn on an individual bit at the specified I O address without affecting the other bits This statement will operate only with I O addresses no
3. 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 MESSAGE lt lt Data gt 255 gt Data gt 65 535 gt Can t LOAD program gt Expected gt Expected gt Expected gt Need more gt Expected gt TO missing gt Expected GOTO gt Expected GOSUB gt Expected THEN gt Expected gt Expected gt Variable name length gt No Autorun program gt Task construction gt CONFIG mismatch gt Command not available gt DO loop counter empty gt Time gt 327 67 sec gt EXPLANATION The argument or parameter may not exceed 255 The argument or parameter may not exceed 65 535 Program does not exist in EEPROM CAMBASIC is expecting a left parenthesis or an expression CAMBASIC is expecting a right parenthesis CAM BASIC is expecting a right bracket Another parameter or argument is expected CAMBASIC is expecting a A TO was missing in a FOR N EXT structure A GOTO is expected after a conditional A GOSUB is expected after a conditional A THEN is expected after a conditional An sign is expected A semicolon is missing in a PRINT statement with a prompt string The variable name is longer than 40 characters CAMBASIC cannot find the autorun program A mismatch of task numbers or task construction has occurred A CONFIG statement was improperly constructed You have used a co
4. NOTE space none In this case a space is required in 8 since all positive numbers are printed with a leading Commands 127 SYS System Function SYNTAX a SYS n PURPOSE To access system data and addresses REMARKS n is the system number The following is a list of system information returned using this function n Function 0 Program size 1 Last address of array variables 2 Bottom of stack 3 Interrupt table address 4 COM 1 output spool count 5 COM2 output spool count 6 COM 1 error flag 7 COM2 error flag 8 Keypad string table address 9 COM input character count 10 COM 2 input character count 11 Buffer full flag for COM1 port 12 Buffer full flag for COM2 port 13 Display row 14 Display column 15 Sparkle flag address RPC 2350G only The SYS function lets you access internal variables within the operating system In most cases you will not need to use this function If you need to find memory that is not used by CAMBASIC you can use all the addresses from the address returned from SYS 1 up to the address returned by SYS 2 Since the stack moves downward it is recommended that you stay at least 300 bytes below the address given by SYS 2 If you execute PRINT SYS 2 SYS 1 in the Immediate Mode the result will be the amount of remaining RAM SYS 1 indicates the last address used by arrays Arrays sit on top of regular numeric variables which in turn are ontop of your program SYS 2
5. ERR 2 lt ERROR 2 gt lt Syntax gt lt Datanegative gt forn lt Data gt 255 gt forn Commands 45 SYNTAX PURPOSE REMARKS EXAMPLE ERROR EXIT and EXIT CLEAR Statement EXIT line label EXIT CLEAR To allow legal branching out of a loop structure Within FOR NEXT GOSUB RETURN and DO UNTIL structures it is sometimes necessary to exit the loop before the loop conditions are met EXIT CLEAR resets all stacks It can be used in emergency stop etc situations where the nesting of loop structures cannot be known EXIT is always used with a ine label unless two or more levels are to be exited When multiple EXITs are used the last one must have a line label EXIT does not work in a DO ENDDO structure 10 GOSUB 50 50 EXIT GOTO 10 60 RETURN Without the E XIT statement the system would eventually crash as the RETURN statement would never be reached 10 GOSUB 20 20 GOSUB 30 30 EXIT EXIT 50 40 RETURN 50 GOTO 10 In this case there is a nested GOSUB structure EXIT must be executed one time for each level of nesting Failure to include two EXITs would have caused a stack imbalance on each pass Eventually you would get a Nesting error message lt Can t compile gt if ine label does not exist lt Syntax gt Trying to exit a non recognized loop or structure Commands 46 SYNTAX PURPOSE REMARKS EXAMPLE ERROR n EXP m To return th
6. NUM 10 11 MESSAGE lt lt Unknown err or gt NEXT w o FOR gt Syntax gt RETURN w o GOSUB gt Out of DATA gt Illegal argument gt Overflow gt Out of memory gt Line label not found gt Subscript out of range gt Array already dimensioned gt Division by zero gt EXPLANATION Error is undefined A NEXT statement is encountered without a matching FOR A line is encountered that includes an incorrect sequence of characters misspelled keyword incorrect punctuation etc A RETURN statement is encountered for which there is no previous unmatched GO SUB statem ent A READ statement is executed when there are no more DATA statements with unread data remaining in the program A parameter that is out of range is passed to a numeric or string function This error may also occur as a result of A negative or unreasonably lar ge subscript A negative or zero argument with the LOG function A negative argument to SQR A negative mantissa with a non integer exponent An improper argument to MID LEFT RIGHT PEEK POKE TAB SPC or ON GOTO f Other function arguments which exceed the limits of the function Qo E TS The result of a calculation is too large to be represented in CA MBASIC single precision format If underflow occurs execution continues without an error A program is too large or has too many loops subroutines and or variables or has expressions that ar
7. REMARKS RELATED EXAMPLE ERROR COS Numeric Function n COS m To return the trigonometric cosine function m must be in radians To convert from degrees to radians multiply by PI 180 where PI 3 141593 Trigonometric functions are computed as a power series in CAMBASIC Calculations are done in single precision floating point to seven digits of precision Since the power series is an approximation the result will be accurate to four to six digits depending upon the value of m ATN SIN TAN 10 PI 3 141593 20 PRINT COS PI 30 DEGREES 180 40 RADIANS DEGREES PI 180 50 PRINT COS RADIANS RUN 1 none Commands 25 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR COUNT Process Function n count channel To return the count in the software event counters and return the count of the hardware counters The COUNT function returns the accumulated high to low transitions at a specified input independent of program execution The software counters are set up using the ON COUNT statement channel is the counter number and ranges from 0 to 7 The RPC 2350 ranges from 0 to 8 Counter 8 is hardware See the Multitasking Chapter for more information CLEAR COUNT CONFIG COUNT ON COUNT RESUME COUNT START COUNT STOP COUNT 10 CONFIG COUNT 0 0 1 20 START COUNT 0 30 PRINT COUNT 0 40 GOTO 30 This example continiously prints counter 0 value lt Illegal argumen
8. C9H However if interrupts have been enabled by CAMBASIC you must consider the consequences or turn off the interrupts Commands 13 NOTE2 CAMBASIC internal routines are not accessible by the object code programmer except those listed inthe SYS function if any NOTE3 The CALL statement saves all the registers needed by CAMBASIC except IY If this register is used it must be restored before returning EXAMPLE CALL 0 This causes the system to reinitialize If an autorun EEPROM is present its program will execute ERROR lt Data negative gt for any parameter lt Data gt 65 535 gt for any parameter Commands 14 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR CHR String Function n CHR m n CHR m n To convert an ASCII code to its character equivalent Also to return a string of like characters The CHR function returns the one character string with ASCII code m CHR is commonly used to send a special character to the screen or printer The second syntax will generate a string of n characters all with the character m This is useful for printing graphics It can be used to simulate SPACE and STRING in other BASICS CHR 65 10 is equal to STRING 10 65 CHRS 32 14 is equal to SPACE 14 ASC STR VAL PRINT CHR 65 A PRINT CHR 36 10 SSSSSSssss lt Data negative gt form n lt Data gt 255 gt form n lt Out of string space gt if
9. ERROR The following shows the use of labels 90 A3 AIN 0 100 GOSUB FILTER 110 PR FL 3000 FILTER 3010 FL 875 FL 125 A3 3020 RETURN lt Can t compile gt if line label does not exist Commands 54 GOTO Statement SYNTAX GOTO line label PURPOSE To branch unconditionally out of the normal program sequence to a specified line number or label REMARKS If line is the line number of an executable statement that statement and those following are executed If it is a non executable statement such as a remark execution continues at the first executable statement encountered after line The GOTO statement can be used in Immediate M ode to reenter a program at a desired point This can be useful in debugging NOTE The execution time of the GOTO statement is independent of the location of the target line in the program There is no runtime search EXAMPLE 10 PRINT line 10 20 PRINT line 20 RUN line 10 line 20 GOTO 20 line 20 The following is an example using line labels 10 start 20 PRINT at start 30 GOTO here 40 there 50 PRINT over there 60 END 70 here 80 PRINT over here 90 GOTO there RUN at start over here over there NOTE When a label is used with GOTO a statement cannot follow GOTO on the same line ERROR lt Can t compile gt if the ine label does not exist Commands 55 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERRO
10. Key interrupt 55 BS KEYPADS 0 60 IF B CHR 13 THEN Get_value 65 IF BS THEN BS 70 AS AS B 75 RETURN 80 Get_value 85 R VAL AS 90 A 95 RETURN Line 30 tells CAM BASIC to call a subroutine by the name of Keypad_interrupt every time a key is pressed Line 35 prints the number that the input string will be converted to Initially it will be zero Line 40 is a 0 25 second delay for demonstration pur poses Line 45 is used only as part of this demo program so that the system will wait You could insert the rest of your control program Line 55 assigns the input to B Line 60 tests to see if this is the terminator key for the input Line 65 tests to see if the input is an asterisk If so it converts it to a decimal point Line 70 adds the new value to the string Line 75 returns program execution to the place that it was executing before the key was pressed Line 85 converts the assembled string into a number Line 90 clear the assembled string to a null string Line 95 returns program execution to the place that it was executing before the key was pressed Fast Branching on Keys Sometimes the input data is in the form of symbols That is rather than numbers and letters the keypads legends might be direction arrows or words like Load and Stop Event Multitasking 10 Intercepting these keys in the form of strings provides a slower response than using the key positions The follow
11. REMARKS RELATED EXAMPLE ERROR INPUT Statement INPUT n var var INPUT n prompt message var var INPUT n prompt message var var The INPUT statement causes the program to pause and prompt an operator for input data The prompt message is a question mark in the first syntax The other two syntaxes specify a message string to be printed before the question mark No question mark is printed if a comma is used in place of a semicolon after the prompt message When the INPUT statement is followed immediately by a semicolon the option the carriage return is suppressed after the last variable The variables may be both numeric and string The data you enter at the prompt must match the variable type Strings do not require the use of quotation marks If a string is entered when a numeric variable is required a lt Redo gt error is given and all the variables must be reentered When multiple variables are used separate the input data with commas If fewer variables are entered than specified with the INPUT statement a prompt will be given for the remainder The only editing you can do on an input line is the backspace You can abort the INPUT statement by executing lt CTL C gt which will also stop the program Even thou gh the serial ports accept any character from 0 to 255 the INPUT statement filters these to the 32 to 127 ASCII set When the is spec
12. ifn gt 7 Commands 125 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR STOP INP Tasking Statement STOP INP n n1 n2 To disable one or more INP tasks declared by the ON INP statement The task parameters are defined by the ON INP statement STOP INP deactivates the task You may specify more than one task parameter so that several tasks may be stopped simultaneously NOTE STOP INP is only executed after a START INP has been executed START INP ON INP See the Multitasking Chapter for more information This demonstration program can be expanded to do more complex tasks The state of the input lines are printed by line 40 After 10 seconds the task is disabled After 30 seconds it is enabled again 10 CLEAR TICK 20 ON INP 0 3 7 5 GOSUB 80 30 START INP 0 40 PRINT BINS INP 0 50 DELAY 25 60 IF TICK 0 gt 10 AND TICK 0 lt 30 THEN STOP INP O ELSE START INP 0 70 GOTO 40 80 PRINT match 90 RETURN lt Datanegative gt forn lt Data out of range gt ifn gt 7 Commands 126 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR STR String Function n STR m To convert a number to a string For positive numbers the string generated by STR has a leading blank See the VAL function for its complem ent ASC CHR VAL 10 AS STRS 3 14159 20 PRINT PI A RUN PI 3 14159 10 A 8 20 IF STRS A lt gt 8 THEN END 30 PRINT OK
13. returns the bottom of the system stack which is below the string stack Be sure to execute this command after using CLEAR n Commands 128 ERROR SYS 3 is used by assembly language programmers to determine jump vector location SYS 4 and SYS 5 return the status of the console output buffer and primary output buffer respectively When zero is returned the buffer is empty A nonzero value means the buffer has some characters to send A nonzero value is not the number of characters left SYS 6 and SYS 7 provide an important data security function when executing the ON COM statement When a parity overrun or framing error occurs on the serial port CAM BASIC branches to your ON COM S interrupt service routine By testing SYS 6 for the COM 1 Port or SYS 7 for the COM2 Port you can determine if the serial data was truncated at the error The SYS 6 and SYS 7 will return 0 if no error has occurred Any nonzero value means an error has occurred and you can request the host to retransmit the data The advanced user may want to know which of the three errors has occurred The SYS function will return 64 for an overrun error 32 for a parity error and 16 for a framing error Keep in mind that an incorrect baud rate could cause any one of these errors since the incoming bits would be out of time synchronization with the UART clock Errors are most likely to occur from noise when using modems or radio links SYS 8 returns the star
14. the data is pushed on the CPU stack for use by the CALLed routine The data could be the memory address obtained by the VAR function of either numeric or string variables if the routine is to access floating point data The amount of data that can be saved on the stack is limited only by available memory When the assembly language routine is entered the information passed and created is structured as follows SP gt mn m n 1 m 1 return address HL gt stack location of return address BC gt number of data The data may then be popped off the stack in reverse order Note the HL register pair point to the location of the return address in the stack allowing a clean return to CAMBASIC The BC register pair contains the number of data passed to the routine Data may be returned to CAMBASIC from the assembly language routine by storing them in memory locations before returning to CAMBASIC and then reading the memory locations from within CAMBASIC with the PEEK function Or they may be stored directly in CAMBA SIC variables if the VAR function was used to pass the variable addresses to the assembly language program NOTEI Once you have called an assembly language routine you are in complete control CAM BASIC has no influence unless the interrupts are left enabled If you do not return to CAMBASIC you probably have not restored the CPU stack or registers destroyed RAM reserved for CAMBASIC or have not executed a RET
15. using a parallel port a UTB terminal board and clip leads 10 ON INP 0 2 7 5 GOSUB 60 20 START INP 0 30 PRINT BINS INP 2 Event Multitasking 7 40 DELAY 25 50 GOTO 30 60 PRINT match 70 RETURN Line 10 defines the INP task 0 to look at address 2 The bits of interest are set by the seven parameters and are bits 0 1 and 2 When the data at the port is ANDed with 7 and the value is 5 bits 0 and 2 are high and bit 1 is low the program branches to line 50 Line 20 prints the binary representation of the port of interest so that you can see the bits pattern while you experiment Line 30 actually starts the tasking process Line 40 creates a small delay so that the binary string printing is easily readable Line 50 repeats the printing Line 60 lets you know that an interrupt has occurred Using START INP and STOP INP As shown in the example above START INP enables the task defined by the ON INP statement Generally the ON INP statements are declared at the beginning of the program for document clarity This also makes the program run faster by not executing these statements in the body ofthe program The START INP executes about three times faster than ON INP The STOP INP halts the task checking temporarily It does not change any of the parameters specified by ON INP Executing another START INP will reactivate the task Tasks can be started and stopped in banks For example 10 START INP 0 1 4 5 7 10
16. 2 30 STOP 40 M CSK 100 PRINT M RUN 1 2 3 lt STOP gt lt Ln 30 gt none Commands 123 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR STOP BIT Tasking Statement STOP BIT task task To disable a bit that has previously been defined with an ON BIT statement and enabled with a START BIT statement You can reenable the task by using the START BIT statement You do not need to re execute the ON BIT statement See the Multitasking Chapter for more information BIT function and statement ON BIT START BIT 10 ON BIT 0 2 0 GOSUB 60 20 START BIT 0 30 PRINT waiting 40 DELAY 5 50 GOTO 30 60 IF BIT 0 0 0 THEN PRINT closed ELSE PRINT open 70 STOP BIT 0 80 RETURN lt Data out of range gt If task number gt 7 lt Datanegative gt for task number Commands 124 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR STOP COUNT Tasking Statement STOP COUNT a LnJ nn To deactivate a software counter task that was previously active This statement is used to suspend a counter that has previously been started The accumulated count is not changed You can restart the counter at the same point by executing START COUNT The range of n is 0 to 7 See the Multitasking Chapter for more information CLEAR COUNT CONFIG COUNT ON COUNT RESUME COUNT START COUNT 10 STOP COUNT 0 1 lt Datanegative gt forn lt Data out of range gt
17. A 1 will suppress the break characters none 10 CONFIG BREAK 1 1 Suppress break on channel 1 lt Data negative gt for com port and mode CONFIG Commands 4 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR CONFIG CLOCK Statement CONFIG CLOCK mode run CONFIG CLOCK run RPC 2350 series only Configures real time clock for 12 or 24 hour modes and starts or stops the clock The TIME function returns the time in 12 or 24 hour formats Set mode 0 for 12 hour time and 1 for 24 hour time format run turns the clock on and off 0 off or stopped 1 on or run TIME DATE CONFIG CLOCK 1 1 Sets to clock to 24 hour mode and starts it running CONFIG CLOCK 1 Starts clock 2350 series only lt Data out of range gt if data other than 0 or 1 are used CONFIG Commands 5 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR CONFIG COMS Tasking Statement CONFIG COM n terminator length XON echo To configure a communication port to interrupt when the programmed conditions are met The CONFIG COM S statement is used in conjunction with the ON COM statement so that the foreground program is interrupted when either a specific message length has been received or a specified termination character has been received n legal serial port number The terminator is equal to the termination character of the incoming string This is normally a carriage return 1
18. BIT 0 1 0N 70 DELAY 05 80 BIT 0 1 0FF 90 GOTO 50 100 pr_count 110 PRINT COUNT 4 120 RETURN Line 10 configures the 82C55 so that port A is an input port and port B is an output port It assumes that the 82C55 is at address 0 Line 20 configures counter 4 so that bit 1 of port 0 is its input Line 30 sets up an interrupt every 1 00 seconds that calls the subroutine to print the count Line 40 starts the counter Line 50 provides a convenient way to get keyboard input Just enter lt ENTER gt when you see the prompt Line 60 forces the output bit high which causes the counter input to go high Line 70 is a short delay Line 80 forces the output bit and the counter input low At this point counter 4 should increment Line 90 sets up the input loop again Event Multitasking 6 Line 110 prints the count in the counter Line 120 returns execution to the place where the one second interrupt occurred You can try this by holding down the lt ENTER gt on your terminal so that it auto repeats and enters count faster INP TASKING INP tasking lets you react to a combination of on off conditions ata digital I O port That is you may want to detect when inputs 0 1 and 7 are high and inputs 2 and 3 are low while ignoring the other input lines 4 5 6 There area total of 8 tasks that can be configured The ON INP statement sets the interrupt conditions The START INP is used to activate the task STOP INP will deact
19. CAM BASIC primarily for those who will be combining object code either from assembly or C programs with CAM BASIC The command set will let you examine and edit memory and single step using the breakpoint feature You enter the Mini Monitor by typing gt MON While in the monitor the prom pt will change from the normal gt to MON gt You can exit the monitor by typing lt Q gt lt RET gt at the monitor prompt MINI MONITOR COM MAND SET The Mini Monitor has eleven commands All data must be entered in hexadecimal If too little data or an illegal command letter is entered the terminal will beep and you will be prompted to start again Entering more than four hex digits for a number produces a system error causing you to exit the Mint Monitor The parameters for the various commands require a space after the command letter and between parameters The Mini Monitor cannot be used with a program line number The command summary is below D Display memory E Edit memory F Filla block of memory M Math add subtract multiply in Hex Q Quit Mint Monitor Display This command is used to examine memory When executed it displays 8 lines of 16 bytes at a time To display the next 128 bytes press the space bar To exit this command press lt RET gt A typical display would be as follows 0 4A90 00 00 60 83 9E 28 9D AE 00 00 20 83 29 29 A8 BA SCS ho D Lt 0 4AA0 20 AE 00 00 OC 86 99 20 E9 0
20. Do this only if all other methods fail Spaces have no affect on speed since they are eliminated in the compiling process Data statements execute slowly If you need large data tables load them into RAM at the start of the program and access them with the PEEK function While this is less convenient it is faster The PRINT USING statement takes longer to execute than PRINT as it must format before sending the characters FPOKE and FP EEK are the fastest memory accesses They move four bytes at a time If you have enough memory to store multiple bytes then use these constructs rather than PEEK POKE DPEEK and DPOKE FPOKE A B is more than twice as fast as POKE A B in an average program Array handling is by its nature slow in any language Avoid multi dimension arrays when possible When possible use the DO ENDDO loop instead of the FOR NEXT It is much faster The most effective way to speed up a program is through good programming Highly modular programs with lots of subroutines and GOSUBs are easy to develop read and maintain However they are slower than optimizing program flow for speed When using a FOR NE XT loop avoid placing the variable after NEXT This forces CAM BASIC to verify the variable name and slow down execution of the loop 10 NEXT fast 10 NEXT D slow Do not use exponent to square or cube a number It is a very slow operation 10 A X 2 very slow 10 A X X fast 10 A X X X better than x 3 Other Tips
21. ELSE END ERL ERR ERROR EXIT EXP FIND FOR FPEEK FPOKE FRE GOSUB GOTO HEX IF Some CPU Cards do not use all of the commands Refer to your hardware C CF NKEY P PUT NSTR NT KEYPAD LEFT LEN LINE LIST LOAD LOCK LOG MID MOD MON NEW NEXT NOT OFF ON OPTO OR OUT PEEK PEEK POKE POKE PR PRINT PRINT USING PRINT PULSE READ REM RENUM RESTORE RESUME RETURN RIGHT RND RUN SAVE SGN SIN SPI SOUND N N ZZ on iil Concepts 4 SQR START STEP STOP STR SYS TAB TAN THEN TICK TIME TO TROFF TRON UNLOCK UNNEW UNTIL USING VAL VARPTR WATCHDOG XOR 4 PO VAVA AS Pg Software and Hardware Interrupts CAMBASIC supports multiple hardware and software interrupts These interrupts causes the program to branch to an interrupt service routine which acts exactly like a GOSUB The syntax of a typical routine is 10 ON KEYPADS GOSUB 50 NOTE Not all products support all the interrupts See your hardware manual for more information Hardware Interrupts CAMBASIC supports up to three hardware interrupts Not all hardware products implement these hardware interrupts See your CPU card user s manual for more information When a hardware interrupt occurs a flag is set If the corresponding ON ITR statement has been previously executed CA MBASIC will sense the flag and cause program execution to branch Branching occurs after the completion of the current stat
22. ERROR ON ERR GOTO Statement ON ERR GOTO Iine label To enable error trapping and specify the first line of the error handling subroutine Once error trapping has been enabled all errors detected by CAMBASIC during run time cause CAMBASIC to branch to the specified line To disable error trapping execute an ON ERR without the line number If the routine beginning at line has an error an infinite loop will be set up In this case do a hardware reset and execute the UNNEW command The error trapping subroutine should be tested before executing an ON ERR statement The ON ERR GOTO line statement must be performed every time an error occurs if you wish to continue to trap on errors The best place to do this is in the error handling routine RESUME RESUME NEXT 10 ON ERR GOTO 100 20 A 5 0 30 END 100 PRINT DIV BY ZERO 110 ON ERR GOTO 100 120 RESUME NEXT In this case just using RESUME without the NEXT would cause line 20 to be executed again producing another error 10 ON ERR GOTO disable error trapping lt Can t compile gt if ine label does not exist Commands 86 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR ON INP Tasking Statement ON INP n address mask compare GOS UB line label To cause an interrupt when a preset input bit pattern is detected in an input port The task is similar to ON BIT However you can look at any or all of the 8 bits on a port An interrupt oc
23. RPC 150 n Oor 1 These correspond to ITR 0 and ITR 1 as described in the hardware manual The ON ITR statement traps a hardware interrupt so software can service it Whena hardware interrupt occurs it sets an internal flag and that interrupt is disabled If an appropriate ON ITR has been declared a program branch will occur Hardware interrupts will remain disabled until a corresponding RETURN ITR statement has been executed If the subroutine ends with just a RETURN the interrupt remains disabled You can cancel an ON ITR at any time by executing the statement without a line number NOTE Not all hardware products implement a hardware interrupt See your CPU card user s manual RETURN ITR 10 ON ITR 0 GOSUB clock 20 30 40 50 clock 60 BIT 1 1 OFF turn whatever off 70 RETURN ITR 0 lt Can t compile gt if line label does not exist lt Command not available gt ifnotimplemented on your card lt Data out of range gt when n isnot0 or 1 Commands 88 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR ON KEYPAD Tasking Statement ON KEY PAD GOSUB line label ON KEYPAD GOSUB ON KEYPAD size GOS UB line lable ON KEYPAD size GOSUB To cause a program branch when any key is pressed on the keypad Using this command without a line label disables keypad tasking The program branch will respond to any key being pressed The interrupt service routine can then filter the charac
24. Sometimes a system will crash without any obvious cause The crashing can occur because part of the memory used by CAM BASIC has been modified by a POKE statement that is out of bounds For example 10 POKE A B The variable A is the address at which the POKE occurs If the value of A inadvertently falls into the wrong area unpredictable results may occur Some of these are a Error message for a nonexistent line number Programing Tips 2 Erroneous error message for a good line A lt System corruption gt error message The system will not respond to the keyboard oaos The program stops or locks up Software interrupts occur as a result of ON COUNT ON KEY PAD ON BIT and similar statements If a second software interrupt occurs while the system is in a subroutine for another interrupt nesting occurs This means that the second interrupt will interrupt the first subroutine After the second subroutine finishes executing the first subroutine can finish executing Use LOCK and UN LOCK if this will cause a problem in your program Nesting can occur at any level limited only by the amount of memory Keep in mind that the last interrupt ultimately has the highest priority while the first interrupt has the lowest priority There is one situation where nesting can cause serious problems Suppose an ON COM statement were issued the conditions were met and you have entered a subroutine If a second interrupt occurs from the same
25. an ON BIT statement You can disable the task using the STOP BIT statement The START BIT statement will start the last task that was declared by the ON BIT statement If you use START BIT without first defining the task with the ON BIT statement CA MBASIC cannot know whether a valid task exists Attempting to start a nonexistent task will usually produce nonsense errors See the Multitasking Chapter for more information BIT function and statement ON BIT STOP BIT 10 ON BIT 0 0 0 GOSUB 60 20 START BIT 0 30 PRINT waiting 40 DELAY 5 50 GOTO 30 60 IF BIT 0 0 0 THEN PRINT closed ELSE PRINT open 70 RETURN lt Data out of range gt If task number gt 7 lt Data negative gt for task number Commands 120 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR START COUNT Tasking Statement START COUNT n nJ nm To activate a software counter task that was previously defined Once one or more counters have been defined by the CONFIG COUNT statement the counter is activated by the START COUNT statement Until that time no counts will be accumulated The range of n is 0 to 7 which is the counter number See the Multitasking Chapter for more information CLEAR COUNT ON COUNT CONFIG COUNT STOP COUNT RESUME COUNT 10 CONFIG COUNT 0 1 0 20 START COUNT 0 lt Datanegative gt forn lt Data out of range gt ifn gt 7 Commands 121 SYNTAX PURPOSE REMARKS RE
26. can be nested inside an ON COM interrupt Event Multitasking does not have a priority system COMS TASKING ON COMS defines a program branch when a task defined by the CONFIG COM statement becomes valid The syntax is ON COMS channel GOS UB line or label ON COMS S channel GOSUB After defining all the parameters with CON FIG COM the ON COMS activates the task You can deactivate the task by executing the same statement but without a line number after GO SUB Channel 1 is COM 1 and Channel 2 is COM2 COM Example In the following example the program will branch when 8 characters have been received The XON and protocol functions are disabled All characters will be echoed 10 CONFIG COM 1 0 8 0 1 20 ON COM 1 GOSUB 80 30 your program goes here 80 PRINT COMS 1 90 RETURN NOTE If a serial reception error occurs the program will branch to line 80 regardless of the number of characters received You can use the SYS 6 or SYS 7 function to determine the cause of the error Event Multitasking 2 COUNT MULTITASKING Introduction CAM BASIC supports eight event counters These are generated in software and are intended for low speed counting Each counter may be assigned through software to any digital I O line on any Control or expansion card Once configured counting is done independently in the background The counters have the following features l The count rate may range from 0 to 80 Hz 2 The counters
27. gt forn lt Illegal argument gt ifn gt 1 Commands 29 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR DEC amp DECF Statements DEC variable DEC F variable To decrement a variable by one DEC or four DECF This is a fast way to decrement a simple or array variable A A 1 slow DEC A fast A A 4 slow DECFA fast DEC executes more than twice as fast as the statement it replaces Valid for simple and array variables INC INCF 10 20 30 40 50 RUN A 4 DEC A PRINT A DECF A PRINT A lt Expected variable gt if parameter is not a variable Commands 30 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR DELETE Command DEL line line To delete CAMBASIC program lines The DEL command erases the specified range of lines from the program CAMBASIC always returns to the Immediate Mode after a DELETE is executed None DEL 10 Deletes line 10 DEL 30 78 Deletes lines 30 through 78 DEL 40 Deletes all lines from the beginning of the program up to and including line 40 DEL 100 Delete all lines from 100 to the end ofthe program To delete the whole program type NEW If you accidentally type NEW you can recover the program by typing UNNEW You cannot recover individually deleted lines WARNING If you specify a deletion range and the second line number does not exist the next higher line number will be deleted DEL doe
28. gt ifn gt 2 lt Time gt 327 67 sec gt for t lt Can t compile gt if line label does not exist Commands 90 SYNTAX PURPOSE REMARKS EXAMPLE ERROR OPTO Process Function a OPTO channel To return the status of an input on an on board opto isolator rack Inputs and outputs are active low when interfacing with opto isolator racks Thus writing a 1 to an opto output module will turn it off This confusion is eliminated with the OPTO function OPTO automatically inverts the logic so thata 1 represents ON and a 0 represents OFF The OPTO function is similar to the BIT function in that individual I O bits or channels can be read It differs in that it is used specifically with opto isolator racks and it executes much faster The channel parameter ranges from 0 to 23 0 3 on the RPC 30 or 100 to 123 and the channel number corresponds to the position numbers on the opto module racks 20 PRINT OPTO 0 RUN In this example the bit 0 of the port at address 0 was set high Since the OPTO function inverts the result a 0 was returned This would mean that there was not input signal at an opto module in this location lt Data negative gt channel lt Illegal argument gt if channel gt 23 Commands 91 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR OPTO Process Statement OPTO channel value To turn output modules on and off on 24 positio
29. gt D 4A90 The number to the left of the colon is the segment number This is displayed only on cards that can have 128K or more RAM MON gt D 4A90 0 4A90 00 00 60 83 9E 28 9D AE 00 00 20 83 29 29 A8 e t a ea NN a 0 4AA0 20 AE 00 00 OC 86 99 20 E9 00 OF 00 50 00 94 sae Pas 0 4ABO D1 28 AE 00 00 OC 00 29 00 21 00 5A 00 81 20 Pe Cre eer ee Z X 0 4ACO A7 AE 00 00 OC 00 98 AE 00 00 60 83 3A 41 A7_ Pete 0 4AD0 28 AE 00 00 60 00 29 3A 82 00 1B 00 64 00 8B Gerd a Pr wd E 0 4AEO D2 28 22 41 53 44 46 22 29 A8 A6 20 AE 00 00 ASDE 0 4AFO 87 99 20 E9 00 1A 00 78 00 8B 20 C7 28 AE 00 S E E 0 4B00 64 89 29 A8 A6 20 AE 00 CO OA 8B 99 20 E9 00 d Commands 80 SYNTAX PURPOSE REMARKS EXAMPLE ERROR NEW and UNNEW Commands UNNEW NEW initializes CAMBASIC fora new program UNNEW restores a program erased by NEW or a hardware reset NEW is used to free memory before entering anew program NEW does not change the memory reserved by the last CLEAR statement The following erases the program pointers for entry ofa new program NEW none Commands 81 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR ON Statement ON expression GOS UB line line ON expression GOTO line line In the ON GOTO statement the value of the expression determines which line number in the list will be used for branching For example if the value is 3 the third
30. keys must be configured to return a lt CR gt 13 or amp D when pressed using the SYS 8 command By default key position 15 returns a lt CR gt A lt CR gt lt LF gt sequence is sent to the echo port when a lt CR gt is sent On all echo ports except the LCD display the line advances The cursor returns back to the beginning of the line on LCD s text is optionally printed to the echo port This is useful as part of a prompt The character following the last quotation determines if a question mark is printed or not A comma suppresses printing a while a semi colon will print one This command must be initialized by ON KEYPAD When INPUT KEYPADS is executed the subroutine specified in ON KEYPA D is not executed Even if you use INPUT KEYPAD as your only keypad input you must havea valid line number specified as part of the ON KEYPAD routine variable is a string for example NAMES or numeric for example WEIGHT As with the regular INPUT statement any string characters entered into a numeric variable prompts for a redo LCD displays do not prompt for a redo but the cursor returns back to the point where it is requesting data KEYPAD ON KEY PAD Commands 63 EXAMPLE ERROR 10 20 30 40 50 ON KEYPADS 24 GOSUB 500 DISPLAY 1 0 INPUT KEYPADS 10 Enter weight WEIGHT PRINT WEIGHT INPUT KEYPADS 10 Enter name NAMES 500 C KEYPADS 1 510 RETURN The ON KEYPA D synt
31. line number in the list will be the destination of the branch NOTE You may not use labels with this statem ent In the ON GOSUB statement each line number in the list must be the first number of a subroutine line must be a number and not a variable Maximum number of line parameters is limited by the number of characters you can put in a line For simplicity no more than 5 line parameters should be used on any one program line If the value of expression is zero or greater than the number of line parameters the statement is ignored RETURN 200 ON R GOTO 150 300 320 390 If R 1 the program goes to line 150 If R 2 the program branches to line 300 and continues from there If R 3 the branch will be to line 320 and so on lt Can t compile gt if line does not exist lt Data negative gt for expression lt Data gt 255 gt for expression Commands 82 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR ON BIT Tasking Statement ON BIT task number ad dress bit GOS UB line label To declare an I O line to be monitored for changes in logic level Any eight I O lines may be monitored so that a change in state causes a program branch to the specified subroutine The I O lines may be located on any parallel port A change of state is either a low to high or a high to low transition The specified line is sampled at each tick of the system clock When the ON BIT statement is executed
32. lt DO loop counter empty gt When a DO loop is nested and the most recent one was completed Commands 38 SYNTAX PURPOSE REMARKS EXAMPLE ERROR DO UNTIL Statements DO UNTIL expression is true To execute a conditional loop structure The DO UNTIL statements cause a list of statements to be executed until a condition is met You may exit a DO UNTIL with the EXIT statement 10 A 45 20 DO 30 INC A PRINT A 50 UNTIL A 0 Nesting DO UNTIL loops is permitted Care must be taken in the construct The following example illustrates one of the possible pitfalls 10 DO 20 DO 30 INC X 40 UNTIL X 5 50 INC Y 60 UNTIL Y 5 In the inside loop beginning at line 20 variable X is incremented until X 5 Line 50 is then executed Since Y is now 1 execution branches to line 20 The previous value of X was 5 and it is now incremented to 6 Since this is greater than 5 the inside loop continues until X overflows a very long time One solution is to add line 45 to reset X each time so the program will run properly 45 x 0 lt UNTIL gt if UNTIL encountered without corresponding DO Commands 39 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR DPEEK and DPOKE Memory Function and Statement DPEE K address DPEEK address segment B DPOKE address data DPOKE address data segment DPEEK returns a 16 bit value from memory DPOKE writes a 16 bit value to
33. memory A 16 bit word is formed with the lower 8 bits as the value located at memory address address and the upper 8 bits as the value located at memory location address 1 The first syntax applies to the first 64K of memory segment 0 For addresses above segment 0 use the second syntax Not all cards support segmented memory DPEEK is an extension of PEEK and executes twice as fast as two PEEK functions DPOKE is an extension of POKE and executes twice as fast as two pokes DPOKE PEEK FPEEK PEEK POKE FPOKE POKE The following routine POKEs or writes two numbers into memory The DPEEK statement allows both to be retrieved and printed 256 x 3 45 813 You could also say DPOKE 2000 813 10 POKE amp A000 45 POKE amp A001 3 20 PRINT DPEEK amp A000 RUN 813 10 A DPEEK 1000 2 This retrieves data from address 1000 at segment 2 lt Datanegative gt for address and segment lt Data gt 65 535 gt for address lt Data out of range gt if segment gt 15 Commands 40 SYNTAX PURPOSE REMARKS EXAMPLE RELATED ERROR EDIT Command EDIT line ee 5 To display a line for editing The EDIT statement simply displays the line specified and positions the cursor under the first character of the line The line may then be modified as described under the Editing Programs Chapter Typing a period will edit the current line EDIT 10 10 A 15 10 _ T
34. must be the last statement on the line If a label follows GOTO or THEN there cannot be an ELSE 10 IF PEEK 5000 27 THEN B 34 ELSE B 12 lt Expected THEN gt if THEN missing lt Can t compile gt if line label does not exist Commands 57 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR INC and INCF Statements INC variable INCF variable To increment a variable by one INC or four INCF INCF is usually used to increment a pointer for floating point number storage This is a fast increment of a simple or array variable A A 1 slow INCA fast A A 4 slow INCF A fast INC executes more than double the speed of the statement it replaces Valid for simple and array variables DEC DECF 10 PRINT H 20 INC H 30 PRINT H RUN 0 1 Line 10 increments element 8 of the array A 10 INC A 8 INCF is used to increment a pointer to a floating pomt number The following example stores 15 floating point numbers to RAM segment 1 fptr amp 1000 do 15 a ain 0 00232 fpoke fptr a 1l incf fptr enddo lt Expected variable gt if parameter is not a variable Commands 58 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR INKEY Function a INKEY n To return a single character from a serial input buffer The returned value is a null or one character length string n valid serial port number 1 or 2 As long as there are characters in th
35. or other character depending upon your system This mode is useful for debugging and for using CAMBASIC as a calculator for quick computations Virtually all statements and commands may be used in this mode Memory may be read and modified Data may be sent to or read from ports The Program Mode is used for entering programs Program lines are always preceded by line numbers Execution begins after RUN is entered The program may be run as many times as desired You can enter a program in either upper or lower case Line Format Every program begins with a line number Line numbers may range from 1 to 65529 Programs are stored and run in RAM in line number order regardless of the entry sequence Programs are compiled into an intermediate code to speed execution The average compiled program will use about 10 more memory than the keystrokes you typed or disk memory used This number can vary 20 either way depending upon the type of program you are writing A compiler limits a program line to 159 characters More than one statement may reside on a line as long as the statements are separated by colons Putting more than one statement on a line will cause somewhat faster program execution and use less memory Line Renumbering CAMBASIC can renumber your program Typing in RENUM will automatically renumber your program in line steps of 10 beginning with line 10 You can optionally specify the starting line number and step value Refer to
36. port The following example is for the KP 1 keypad It uses the default assignment of a carriage return 13 for the key This is necessary as a string input must be terminated with the carriage return 30 INPUT KEYPADS 1 A 40 PRINT A Line 30 is the input statement The parameter 1 tells the system to echo the keypad characters to Event Multitasking 11 the COMI serial port In an actual application the characters would probably be echoed to a multi line display Enter the data and then press the key Line 40 will print out the string Event Multitasking 12 MULTITASKING ON A CLOCK TICK The three 200 Hz 100 Hzin9 MHz systems tick timers are used for a number of multitasking functions in CAMBASIC In multitasking it is used as a periodic interrupt The ON TICK statement can call a subroutine as often as 200 100 in 9 MHz systems times per second or once every 327 67 seconds The syntax is ON TICK number time GOS UB line label On every multiple of the specified time program execution branches to the subroutine at the Jine label Program execution resumes when the RETURN statement is reached in the subroutine A simple exam ple would be as follows 10 ON TICK 0 1 GOSUB 50 20 PRINT foreground 30 FOR C 0 TO 1000 NEXT 40 GOTO 20 50 INC Ab 60 PRINT A 70 RETURN Line 10 tells CAMBASIC to interrupt every 1 00 seconds and branch to line 50 Lines 20 through 40 represent a foreground program It print
37. printed items If the list of expressions terminates without a semicolon or a comma a carriage return is printed at the end of the line Printed numbers are always followed by a space Positive numbers are preceded by a space Negative numbers are preceded by a minus sign n valid port number Port numbers are 1 and 2 for serial 9 for VF display 10 for LCD display LCD and VF displays must be configured using the CONFIG DISPLAY command before use RPC 2350 NOTE The CAMBASIC statement BIT 128 4 0 may need to be executed before you will receive any characters This command enables the CTS line PRINT PRINT USING TAB CHR In the example below the semicolons in the PRINT statement cause each value to be printed in the same line 10 x 5 20 PRINT X 5 X 5 X 5 RUN 10 0 25 The following is an example of string concatenation The output is through the COM2 serial port 30 A Hi 40 B there 50 PRINT 2 A B RUN Hi there Commands 96 ERROR In the example below the semicolon at the end of line 20 causes both PRINT statements to be printed on the same line 10 INPUT X 20 PRINT X Squared is X 2 and 30 PRINT X Cubed is X 3 RUN 9 9 Squared is 81 and 9 Cubed is 729 001 RUN 21 21 Squared is 441 and 21 Cubed is 9260 99 This exam ple prints a message to the COM2 port 100 PRINT 2 Pressure A In this example the comma in the PRINT statement causes each value to be pri
38. removed in the compiling process They are added back when you type LIST Order The set of arithmetic and logical operators available in CAM BASIC in the order in which they are evaluated is as follows 1 expressions in parentheses 2 exponent 3 unary minus 4 and multiplication and division ay and addition and subtraction Concepts 12 6 relational operators equal lt gt not equal lt less than gt greater than lt less than or equal to gt greater than or equal to Ts NOT logical bitwise complem ent 8 AND logical bitwise and 9 OR logical bitwise or 10 XOR logical bitwise exclusive OR 11 MOD remainder from integer divide All operators listed at the same level are evaluated left to right in an expression All logical operations convert their operands to 16 bit integer values prior to the operation These operands must be in the range 0 to 65 535 or 32 768 to 32 767 If they exceed these values the result will be meaningless and no error message will be given Concepts 13 CAMBASIC EDITOR Using the Line Editor When using a CRT terminal to write programs the resources of the PC are not available CAMBASIC has a line editor that may be used with any smart or dumb terminal You can also use these commands when using your PC with terminal software other than PC SmartLINK There are 12 editing commands Your program can be e
39. the specified line is sampled for the current state The task does not become active until the START BIT statement is executed The STOP BIT statement will disable the event The BIT task number ranges from 0 to 7 address ranges from 0 to 65 535 bit ranges from 0 to 7 line label may be any valid program line number or label See the Multitasking Chapter for more information START BIT STOP BIT 10 ON BIT 0 0 0 GOSUB 60 20 START BIT 0 30 PRINT waiting 40 DELAY 5 50 GOTO 30 60 IF BIT 0 0 1 THEN PRINT closed ELSE PRINT open 70 RETURN lt Data negative gt for task address bit lt Data out of range gt if bit task or bit gt 7 lt Data gt 65 535 gt for address lt Can t compile gt if ine label does not exist Commands 83 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR ON COMS Tasking Statement ON COM n GOSUB Jine label ON COMS n GOSUB To define a program branch when a task defined by the CONFIG COM statement becomes valid After defining all the parameters with CONFIG COM the ON COM activates the task You can deactivate the task by executing the same statement but without a line number after GOSUB n legal serial port number See the Multitasking Chapter for more information CLEAR COM COM CONFIG COM 10 CONFIG COM 2 0 8 0 1 20 ON COM 1 GOSUB 80 30 your program goes here 80 PRINT COMS 2 90 RETURN In this example the program w
40. to calendar clock Stops the trace Starts the trace Re enab les software interrupts Restores a program Formats a printed output Converts m to a number Returns address of variable Performs a logical exclusive OR Lists entire program to screen Command Summary 7 SYNTAX PURPOSE REMARKS RELATED EXAMPLE Error n ABS m To return the absolute value of the expression m The absolute value of a number is always positive or zero none PRINT ABS 7 7 PRINT ABS 7 7 none Commands 1 ABS Numeric Function SYNTAX PURPOSE REMARKS EXAMPLE ERROR AIN Process Function a AIN channel To return the analog input value The channel is the channel number of the A D converter The maximum channel number varies from card to card See your hardware manual for more information See your hardware manual lt Data negative gt for all parameters lt Illegal function gt if channel too large lt Command notavailable gt if function not supported in your card Commands 2 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR AND Numeric Function n a ANDb Performs bitwise or logical operation on two numbers AND ing is usually performed during I O operations to seta line low Variables a and b are in the range of 0 to 65 535 amp FFFF When printed numbers greater than 32 768 are negative Logical AND ing is performed during IF T
41. to run another program Program execution always starts at the first program line The third syntax from memory segment refers to the physical memory map and is in the range of 0 to 15 Segments 0 7 are always RAM while segments 8 15 are always Flash EPROM The number of segments actually available depend upon memory size for each type 128K RAM uses segments 0 and 1 128K Flash use segments 8 and 9 A 512K RAM uses segments 0 7 while a 512K flash uses segments 8 15 The third syntax is useful for moving blocks of memory around from Flash to RAM or RAM to RAM Using proper addressing you can move and replace CA MBASIC arrays in RAM Use the SAVE command to store to Flash LOAD Loads a program from F lash segment 0 LOAD n Loads a program from F lash segment 0 to 7 LOAD 1 weight 1 amp 9000 4500 Loads 4500 bytes of data to RAM segment 1 address weight from Flash segment 1 address amp 9000 LOAD 1 RUN Load program from Flash segment 1 and runs it lt Data negative gt for address or length lt Data gt 65 535 gt for address or length lt Data gt 2 or 7 gt for segment Commands 74 SYNTAX PURPOSE REMARKS EXAMPLE ERROR LOCK UNLOCK Tasking Statements LOCK UNLOCK RETURN UNLOCK EXIT To lock out interrupts from time critical portions of a program When an interrupt occurs from a ON TICK ON COMS etc the current program is interrupted and the interrupt subroutine is called In s
42. to the language and also some limitations 2 CAM BASIC does not support disk or direct video commands on 64180 systems 3 CAM BASIC has an automatic floating point math system which automatically converts from floating point to integer and back as needed Values are always stored in floating point The floating point is single precision with seven digits of precision that are rounded to six digits when printed 4 While variable names may be as long as 40 characters only the first and last characters and the length are significant This allows for more than 25 000 variable nam es 5 CAM BASIC does not support the following BASIC A and GW BASIC non disk commands BEEP CINT CIRCLE COLOR KEY LINE INPUT LOC LOCATE LOCK LPOS LSET RSET OCT ON PEN ON PLAY ON STRIG PAINT PALETTE PEN PLAY PMAP POINT POS PUT RANDOMIZE SCREEN SOUND SPC STICK SYSTEM UNLOCK USR VIEW WAIT WHILE WEND and WRITE QBASIC does not support the following C AMBA SIC commands AIN BCD BIN CONFIG COUNT DEC DECF DISPLAY DO DPEEK DPOKE EXIT FPEEK FPOKE INC INCF ITR KEYPAD ON BIT ON COUNT ON INP ON ITR ON KEYPAD ON TICK PEEK POKES PRINT RESUME COUNT RESUME TIMER START BIT START COUNT START INP START TIMER STOP BIT STOP COUNT STOP INP STOP TIMER SYS and TICK 6 CAMBASIC supports hardware interrupts while the others do not Differences 1 THE CAMBASIC MINI MONITOR The Mini Monitor is included in
43. 0 40 PRINT VARPTR T 0 RUN 17484 17490 In this example the variable W is first used after the array address was printed Thus the array address is shifted by the six bytes required for a simple variable 10 A Tuesday 20 R VARPTR AS 30 PRINT CHR PEEK R T In this case new variables are declared after VARPTR returned the address Unlike the array case Commands 138 the value returned will not change Commands 139 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR XOR Numeric Function n aXORbDb Performs bitwise XOR operation on two numbers XOR ing is usually performed during I O operations to toggle a line Variables a and b are in the range of 0 to 65 535 amp FFFF When printed numbers greater than 32768 are negative OR AND 10 A INP 0 get current status of port 20 A A XOR 2 Toggle bit number 1 30 OUT 0 A output new status 40 PRINT A RUN 8 none Commands 140 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR CONFIG AIN Statement CONFIG AIN channel input range Where channel is 0 to range of inputs for your card input specified single ended or differential if supported on your card range is voltage input if supported on your card Initialize analog inputs Refer to your hardware manual for power up defaults input and range parameters if any The RPC 2300 is not configured while the RPC 2350 is configured for 0 5 V single end
44. 0 OF 00 50 00 94 eel Pays 0 4AB0O D1 28 AE 00 00 OC 00 29 00 21 00 5A 00 81 20 Cae ats Z X 0 4ACO A7 AE 00 00 OC 00 98 AE 00 00 60 83 3A 41 A7_ ey rae 0 4AD0 28 AE 00 00 60 00 29 3A 82 00 1B 00 64 00 8B Metts itis aca ss 0 4AE0 D2 28 22 41 53 44 46 22 29 A8 A6 20 AE 00 00 ASDF 0 4AF0 87 99 20 E9 00 1A 00 78 00 8B 20 C7 28 AE 00 teh meretas a s 0 4B00 64 89 29 A8 A6 20 AE 00 CO OA 8B 99 20 E9 00 d To display memory in segment one or higher see the following example which will display RAM memory in segment 1 starting at address 0 MON gt D 0 1 Mini Monitor 1 Edit Memory This routine lets you poke hex values into memory For example to edit at A000 you enter the command below The prompt is for the data Enter the data and type lt RET gt The data and addresses will then be displayed for easy verification MON gt E A000 01 22 4D C3 20 00 7A 23 C9 A000 01 A001 22 A002 4D A003 C3 A004 20 A005 00 A006 7A A007 23 A008 C9 This command can only be used in segment 0 since this is the only segment where code may be executed Fill Memory This command may be used to fill a block of memory It is often used to zero a section of memory where data will be stored to make the detection of the data easier when debugging The syntax is F start address end address data segment All the memory locations from the start through the end address will be filled with the da
45. 00000000 to 11111111 can be represented 10101010 170 lt gt Characters within lt gt indicate a single keystroke NOTE Information under this heading presents helpful tips for using CAMBASIC CAUTION Information under this heading shows you how to avoid potential problems WARNING Information under this heading warns you of situations which might cause catastrophic or irreversible program damage gt _ This symbol indicates the prompt gt and the cursor position _ A column of periods is used in program examples to indicate that a portion of the program is omitted This symbol indicates special variables address Indicates any address from amp 0000 to amp F FFF or 0 to 65535 n m Lower case letters a thru z are used to represent quantities or expressions They are not CA MBASIC variables segment Refers to a 64K block of memory string When used as part of a function or command string may be a variable or text enclosed in quotes Brackets indicate that the item enclosed is optional Means that parentheses are required bit Indicates the bit number from 0 to 7 of an I O address Text in this type style is sample code Preface 1 PRODUCT SUPPORT If you have a question about CAMBASIC and you cannot find the answer in this manual call Technical Support at the number listed below during normal business hours They will be ready to give you the support you need to successfully use CAMBASIC wit
46. 3 but it may be any character from 1 to 127 If you specify 0 CAMBASIC will not test for a terminator In some cases there is no termination character The length of the message is always the same In this case the ength parameter should be set to the message length The range is 1 to 127 characters If you specify 0 CAMBASIC will not check for length The XON parameter enables or disables XON X OFF protocol checking by the serial port Setting this parameter to 1 enables the protocol and setting it to 0 disables the protocol The echo parameter determines when the incoming characters are to be echoed When a 1 is specified the characters are echoed Characters are not echoed when the parameter is 0 See the Multitasking Chapters for more information RPC 2350 NOTE The CAM BASIC statement BIT 128 4 0 may need to be executed before you will receive any characters This command enables the CTS line to the sender ON COM COM 10 CONFIG COM 2 13 0 0 0 This example configures COM2 so that the terminator is a carriage return There is no length checking XON XOFF protocol and no character echo lt Data negative gt forn terminator length XON echo lt Data out of range gt ifn isnotl 2 or 3 terminator or length gt 127 XON or echo gt 1 CONFIG Commands 6 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR CONFIG COUNT Tasking Statement CONFIG COUNT aumber
47. 34 INPUT PH METER READING Numeric constants are positive and negative numbers Numeric constants cannot contain commas All CAMBASIC constants are in the range from 1 7E 38 to 1 7E 38 Numbers are assumed to be decimal unless an amp or prefix is present The amp is a hexadecimal prefix for numbers from amp 0 to amp FFFF The is a binary prefix for numbers from 00000000 to 11111111 Up to seven digits decimal of precision may be specified Some examples are 123 1 5678E 34 00110101 567 15E 10 34 9 amp 8200 Numeric constants numbers are compiled as entered The compiled code takes five bytes per constant regardless of the number of digits in the constant Using constants other than variable names in your program speeds execution at the expense of memory Due to the compiling process the maximum number of constants per line is 24 Exceeding that number will invoke the Compile error message Concepts 8 NOTE Attempting to enter a line with more than 24 constants will cause the remainder of the line to be terminated CAMBASIC does this to prevent serious program malfunction If you create a program on a PC and try to download a line with more than 24 constants CAM BASIC will try to send an error message Subsequent lines will become garbled as the synchronous nature of data transmission is lost When numeric constants are printed in a program listing they are always followed b
48. C reserves 100 bytes for strings on power up Using the CLEAR statement more or less memory may be reserved The reserved memory is shared by all the strings String constants do not use any of the reserved space For example 10 AS This is a string constant does not use any of the reserved space as the string is a constant In the example below A and B do not use reserved string space but C does 10 AS Hello 20 BS there 30 CS AS BS In this example only B uses reserved space 10 A 20 B Hello A Strings may be compared using the same relational operators that are used with numbers Adding or concatenating equal gt not equal greater than less than greater than or equal less than or equal A VA VA Consider the following program The string operators are 10 A ABC 20 BS ABD 30 IF A gt B THEN PRINT YES ELSE PRINT NO RUN NO Strings are compared on a character by character basis In the example above B is greater than A as the ASCII value of D is greater than that of C Concepts 7 Lower case characters have a higher ASCII value than upper case characters If two strings are identical up to the point that one string ends the shorter string is said to have a lower value Array Variables An array is a group or table of values referenced by the same name Each individual value in the array is called an element Array elements are variables and
49. COPYRIGHT Copyright 1988 1994 Octagon Systems and Remote Processing Corp All rights reserved Modifications by Remote Processing Corporation Copyright 1995 2003 The software described in this manual is furnished under a license agreement and may be used only in accordance with the terms of the agreement The contents of this manual and the specifications herein may change without notice TRADEMARKS CAM BASIC Micro PC PC SmartLINK and Event Multitasking are trademarks of Octagon Systems IBM PC is a registered trademark of IBM Corporation QBASIC is a registered trademark of Microsoft Corporation Remote Processing Corp 7975 E Harvard Ave Denver CO 80231 Phone 303 690 1588 FAX 303 690 1875 www rp3 com Order 1042 Rev 1 6 HOW TO USE THIS MANUAL This manual contains information on CAMBASIC and its commands You will find that some information is duplicated in this manual This is done on purpose as you will probably want to skip over some sections to read those of imm ediate interest We have included caution and warning notes that are designed to steer you away from potential trouble areas Symbols And Terminology Throughout this manual the following symbols and terminology are used amp A prefix amp denotes a hexadecimal number A decimal number has no prefix For example amp 1000 and 4096 are equivalent A prefix denotes a binary number Only numbers from 0 255 or
50. Data gt 65 535 gt for address CONFIG Commands 10 PROGRAM DEBUGGING CAMBASIC has several constructs which can be used to debug a program This section will outline the methods and give examples Using the STOP statement When a STOP statement is encountered program execution halts and the line number containing the stop statem ent is displayed By inserting the STOP statement in different sections of the program you can determine whether these sections are being executed For example you can test a conditional branch 10 INPUT A 20 IF A 2 THEN 50 ELSE 80 30 40 50 B 23 55 STOP 60 70 B 25 75 STOP 80 In this example a line number followed by a remark statement means that this line would bea part of your program In the example above STOP statements are inserted at lines 55 and 75 to determine if the branch at line 20 is operating correctly When you input 2 the program should stop at line 55 Otherwise it should always stop at line 75 USING THE PRINT AND INPUT STATEMENTS The example above shows how the INPUT statement can be inserted so that you can manually change the value of X to test this program fragment The PRINT statement can also be used to print out the value of any variable or memory location after the program has halted TRON TROFF TRACES EXECUTION PATHS TRON turns on the line num ber tracing function Line numbers are printed as they are executed No other information is pri
51. EM used in other Basics The format provides a more readable remark The old REMARK syntax 10 REM test comments is not allowed 10 test comments is required Remark statements are not executed but are output exactly as entered when the program is listed Remarks are skipped over during execution Thus if memory allows you may leave all your remarks in your final application software with no sacrifice in speed The extra memory required is usually insignificant compared to the additional clarity achieved with the addition of remarks If you put a remark on a line with other CAMBASIC statements the remark must be the last statement on the line and be preceded with acolon Any statements following the remark are ignored This format may be used to designate line labels The maximum length is 159 characters 120 calculate average velocity 130 FORI 1 TO 20 140S S VQ 150 A 0 initialize A none Commands 104 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR RENUM Command RENUM newline increment oldline To renum ber program lines newline is the first line number to be used in the new sequence The default is 10 increment is the increment to be used in the new sequence The default is 10 oldline is the line in the current program where renumbering is to begin The default is the first line of the program RENU M also changes all line number references to reflect the new line numbers
52. HEN operations to test if all conditions are met OR XOR 10 A INP 0 get current status of port 20 A A AND amp FE set bit number 1 low 30 OUT 0 A output new status 40 PRINT A RUN 8 Use AND in an IF THEN statement to make sure all conditions are true 10 IF TEMPERATURE gt 100 AND HUMIDITY lt 5 THEN GOTO dry When the variable TEMPERATURE is more than 3 and variable HUMIDITY lt 25 then the condition is true In this case AND returns a true non zero condition none Commands 3 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR AOT Process Statement AOT channel value To write data to a analog output port AOT causes the analog output voltage to move to a level specified by the value The voltage will remain constant until another AOT statement is executed The analog output ICs change voltage as fast as the CPU can write to them See your hardware manual for more information CONFIG AOT See your hardware manual lt Data negative gt for channel and value lt Data out of range gt if channel too large lt Command not available gt if card does not have hardware support Commands 4 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR ASC Numeric Function n ASC m To return the ASCII code for the first character of the string m The result of the ASC function is a numerical value that is the ASCII code of the first character of t
53. IC checks to see if any interrupt flags are set If so it branches to the line number that was specified for that interrupt The maximum time to service an interrupt is the length of the command previous to the interrupt This is called maximum latency time It ranges from about 0 2 milliseconds to 2 milliseconds There are a few exceptions The INPUT and INPUT KEYP AD statements will ignore interrupts until the input is received The DELAY statement will prevent a response to an interrupt until the delay period If the serial output buffer becomes full and there are still more characters to put in the buffer interrupts will not be serviced until all the characters are in the buffer Interrupt Priorities CAMBASIC does not have an interrupt priority scheme However you can lock outa response to an interrupt for critical program segments with the LOCK command CAMBASIC allows nesting of interrupts That means an interrupt service routine can interrupt another interrupt service routine If there are two interrupt routines A and B and A has partly executed when B interrupts B will execute to conclusion and then A will finish Thus the routine that occurred last in effect has the highest priority Since the sequence of the incoming data must be preserved ON COMS interrupts are internally stacked in CAMBASIC such that each ON COM interrupt will be handled in its entirety before the next one occurs Other types of interrupts such as ON TICK
54. ISPLAY L x y Text Print large size characters DISPLAY L R x y Text Print large size characters in revers color format Medium size characters are position based on a graphical X and Y pixel position When printing a string characters automatically advance to the right X Y coordinates specify the upper right corner of the character block Large size character position is based on pixel and small character resolution X position starts based on small character set For a 320 x 240 pixel display maximum X position is 34 Y position sets the top of the character Character fonts are stored in flash and may be changed Refer to your hardware manual for more information Text can be a number or the CHR command Be sure to terminate the command with a semi colon Leaving it out will send a lt CR gt lt LF gt sequence 2 spaces to the display CONFIG DISPLAY The example below is for the LC D 4x40 display Notice that all DISPLAY statements end with a semicolon so that a carriage return line feed will not be sent 10 CONFIG DISPLAY amp 40 7 0 20 A PRESENTING 30 B 40 C 160 Character LCD display 50 D with LED backlighting 60 DISPLAY 0 5 AS 70 DISPLAY 1 14 B 80 DISPLAY 2 6 C 90 DISPLAY 3 8 D 100 DELAY 2 110 DISPLAY 0 0 CHR 32 80 120 DISPLAY 2 0 CHR 32 80 130 DELAY 5 140 GOTO 60 Line 10 installs the driver for the LCD 4x40 at address am
55. IT END ERL ERR ERROR EXIT EXIT CLEAR EXP FIND FOR NEXT STEP FPEEK FPOKE FRE GOSUB GOTO HEX IF T HEN EL SE INC INCF INKEY INP INPUT INPUT KEYPAD INSTR INT KEYPAD LEFT LEN Syntax DO list UNTIL expr DOn n DPEEK address DPOKE address data EDIT line END n ERL n ERR ERR 7n EXIT line EXIT CLEAR n EXP m FIND variable command FOR x m TO n STEP a FPEE K address segment FPOKE address data segment n FRE 0 n FRE c GOS UB line label GOTO line label n HEX m IF condition THEN ELSE INC variable INCF variable a INKEYS n n INP O address INPUT string var INPUT KEYPAD a a INSTR v a b n INT b a KEYPA D n n LEF T m p n LEN m Purpose Executes until expression is true Fast loop structure Returns 16 bit value from memory Writes 16 bit value to memory address Displays a line for editing Causes program execution to cease Returns line number associated with error Returns error code associated with error Simulates run time error Allows branching out of a loop Resets all loops and stacks Returns exponential function of e Searches for parameter in program Do a loop for n times Returns floating point number from memory Stores data in memory Returns free program and data bytes Returns unused string space Branches to a subroutine Branches to specified line number Returns hex representati
56. LATED EXAMPLE ERROR START INP Tasking Statement START INP a Lal n2 To enable one or more INP tasks declared by the ON INP statement The task parameters are defined by the ON INP statement START INP activates the task NOTE You must execute an ON INP statement first for each corresponding START INP You may start more than one task ata time STOP INP ON INP See the Multitasking Chapter for more information This demonstration program can be expanded to do more complex tasks The state of the input lines are printed by line 30 10 20 30 40 50 60 70 ON INP 0 3 7 5 GOSUB 60 START INP 0 PRINT BINS INP 0 DELAY 25 GOTO 30 PRINT match RETURN lt Data negative gt forn lt Data out of range gt ifn gt 7 Commands 122 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR STOP Statement STOP To terminate program execution and return to command level STOP statements may be used anywhere in a program to terminate execution When a STOP is encountered the following message is displayed lt STOP gt lt Ln nnn gt where nnn is the line number where the STOP occurred CAMBASIC always returns to command level after a STOP is executed Execution is resumed by issuing a CONT command see CONT Command SOUND and multitasking are turned off when STOP is executed A CONT may cause unexpected program operation CONT 10 INPUT A B C 20 K 5 L 3
57. MODE LINE EDITOR To start this tutorial on editing power up your system and enter the following line 10 PRINT This is PRINT a sample edit Now type EDIT 10 10 PRINT This is PRINT a sample edit 10 Program Editing 1 Executing the EDIT statement will cause the target line to be displayed Below this line the line number will be displayed again and the cursor will be positioned at the start of the line In the following text the notation lt ENTER gt means press the key enclosed by the lt gt The underline shows the cursor position CURSOR MOVEMENT The display will appear as above Press lt SPC gt twice You will notice that the first two characters appear as the cursor moves to the right Now press lt 4 gt and then lt SPC gt The cursor now moves 4 spaces to the right Press lt SPC gt twice The characters seem to be erased but are not You can confirm this by pressing lt SPC gt twice again You cannot move the cursor with the lt SPC gt beyond the end of the line or with the lt SPC gt to the left of the text Editing the line number is not allowed Now press lt ENTER gt The line is reprinted and then saved In this case no editing took place This line will be used throughout this section Now type a period 9 You will notice that line 10 once again appears for editing This is the quick form of editing The command causes the current line to b
58. ON COM statement it will interrupt itself The effect of this is that the second interrupt may change variables that the first interrupt has yet to use You can avoid this situation by either disabling the ON COM statement while you are in an interrupt routine or preventing the sender from sending more data until you have processed the first data A good rule of the thumb is that all interrupt service routines should be as short as possible Before downloading a program from the PC always type NEW if a program already exists This will speed up the download When doing a comparison on the result of multiple calculations rounding errors can cause a comparison to be missed In the example below A is the result of multiple calculations the variable A below could increase from 1 22999 to 1 23001 and the equality would not be met 10 IF A 1 23 THEN 100 A better method is 10 IF A gt 1 23 THEN 100 Programing Tips 3 Command Syntax Purpose ABS AIN AND AOT ASC ATN AUTO BCD BIN BIN BIT BIT CALL CHR CLEAR CLEAR COM CLEAR COUNT CLEAR PULSE CLEAR TICK CLS COM CONFIG CONT COS COUNT DATA DATE DEC DECF DELETE DELAY DIM n ABS m n AIN channel n aANDb AOT channel value n ASC m n ATN m AUTO line increment n BCD m n BIN m a BINS m n BIT W O address bit BIT addr bit value CALL addr m1 m2 n CHR m n CHR m n CLEAR string space CLEA
59. OSE REMARKS RELATED EXAMPLE ERROR CLEAR TICK Tasking Statement CLEAR TICK n To reset the internal TICK clock to zero This does not affect a calendar clock or the counter for the ON TICK statem ent There are three TICK timers in CAMBASIC The parameter n is the timer number and the range is 0 to 2 All TICK timers are independent This statement can be used as an electronic stop watch It can be used in conjunction with the ON BIT statement to measure how long an input is active See the Multitasking Chapter for more information ON TICK TICK 10 CLEAR TICK 0 20 IF BIT amp 18 0 1 THEN 20 30 PRINT TICK 0 RUN 37 20 This example measured the elapsed time for bit 0 of address amp 18 to go high lt Data out of range gt ifn gt 2 lt Datanegative gt forn Commands 19 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR CLEAR PULSE Tasking Statement CLEAR PULSE n n1 nm To clear the remaining time in a software timer and restore the I O line polarity Once a timer has been started using the PU LSE statement a CLEAR PULSE statement is used to abort the timing sequence The output bit polarity specified in the PULSE command is restored to the inactive state PULSE statement and function 10 CLEAR PULSE 1 10 CLEAR PULSE 0 1 2 3 4 lt Data negative gt forn lt Data out of range gt ifn gt 7 Commands 20 SYNTAX PURPOSE REMARKS E
60. R n HEX m To return a hex representation of a number The value of m may range from 0 to 65 535 HEXS String Function If the number is 255 or less HEX returns a two hex digit result Larger numbers result in four hex digits being returned none PRINT HEXS 127 7F PRINT HEX 1280 0500 lt Data negative gt form lt Data gt 65 535 gt for m Commands 56 SYNTAX PURPOSE REMARKS EXAMPLE ERROR IF THEN ELSE Statement IF m THEN statement s ELSE statement s IF m GOTO line label IF m THEN Jine label To make decisions regarding program flow based on the results returned by an expression If the expression m is true not zero the THEN clause is executed THEN may be followed by either a line number for branching or one or more statements to be executed If the result of m is false zero the THEN line is ignored and the ELSE line if present is executed Other wise execution continues with the next executable statem ent THEN or ELSE may be followed by either a line number for branching or one or more statements to be executed IF THEN ELSE statements may be nested 10 IF A B THEN C 2 ELSE IF A J THEN PRINT J If an IF THEN statement is followed by a line number in the Immediate Mode a lt Line not found gt error results unless a statement with the specified line number had been previously entered in the Program Mode NOTE If a label is used it
61. R COM n CLEAR COUNT n CLEAR PULSE n CLEAR TICK n CLS n n COM n CONFIG n CONT n COS m n COUNT m DATA constant a DAT ES n DATES string DEC variable DECE variable DELETE Jline line DELAY n DIM variable value Returns absolute value of a number Returns result of A D conversion Performs logical AND Sends data to a D A converter Returns ASCII code for first character Returns the arctangent Generate line numbers auto matically Converts binary to BCD Converts packed BCD to binary Converts 8 bit number to string Reads specific bit at address Writes bit at address Call assem bly program and pass data Converts number to character equivalent Converts number m character n times Clears variables sets string space Resets serial input buffer Clears count in software counter Clears remaining time in software timer Resets an internal system clock to 0 Clears screen Returns string from serial input buffer Initializes system parameters Resumes program execution Returns cosine of m to n Returns the count in software counters Stores numeric and string data Returns date from calendar clock Writes to calendar clock Decrements variable by 1 Decrements variable by 4 Deletes CAMBASIC program lines Delays program by n seconds Specifies max size for array variables Command Summary 1 DISPLAY DISPLAY a Writes data to display Command Summary 2 Command DO UNTIL DO ENDDO DPEEK DPOKE ED
62. RELATED EXAMPLE ERROR TICK Process Function a TICK n To return the time from the TICK timers n is from 0 to 2 corresponding toa tick timer There are three TICK timers in CAM BASIC that accumulate on a 12 hour basis These are separate from the calendar clock and are not battery backed The functions return the time in 0 005 0 010 in 9 MHz systems second increments up to 12 hours Using the process clock has an advantage over the calendar clock in that you deal only with seconds and not hours and minutes On power up all TICK timers start at 0 0 and begin counting You can reset the process at any time by using the CLEAR TICK statement The process clock cannot be preset to a value other than 0 using CLEAR TICK These tick counters are separate from those used in ON TICK CLEAR TICK ON TICK 10 CLEAR TICK 2 20 FOR X 0 TO 5000 NEXT 30 PRINT TICK 2 RUN lt Datanegative gt forn lt Data out of range gt ifn gt 2 Commands 132 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR a TIME n TIME Function The TIME function is used to read the system calendar clock The system clock keeps time on a 24 hour basis with a resolution of one second The time is returned in two forms depending upon the value of the argument n When n 0 the hours minutes and seconds are returned When n 1 the minutes and seconds are returned The clock is set by the TIME statemen
63. RENUM may not be used to change the order of program lines Nor can it be used to create line numbers greater than 65 529 AUTO RENUM Renumbers the entire program The first new line number will be 10 Lines will increment by 10 RENUM 300 50 Renumbers the entire program The first new line number will be 300 Lines will increment by 50 RENUM 1000 1 20 Renumbers the lines from 20 up so they start with line number 1000 and increment by 1 lt Line not found gt newline or oldline does not exist lt Subscript out of range gt if attempt is made to RENUM past line 65 529 Commands 105 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR RESTORE Statement RESTORE line To reset the READ pointer to the beginning of the DATA list After a RESTORE statement is executed the next READ statement accesses the first item in the first data statement in the program If the optional ine number is specified the next READ statement accesses the first item beginning at the line number specified NOTE Labels may not be used with RESTORE DATA READ 10 READ A B C 20 RESTORE 30 READ D E F 40 DATA 12 34 56 50 PRINT A B C D BE E RUN 12 34 56 12 34 56 lt Can t compile gt if optional line does not exist Commands 106 SYNTAX PURPOSE REMARKS RELATED ERROR RESUME Statement RESUME RESUME NEXT RESUME line To continue program execution after an err
64. STOP INP 2 3 4 KEYPAD MULTITASKING CAM BASIC has built in keypad scanner and debounce software When activated a keypad is scanned in the background When a key press is detected the system waits 80 mS and tests again If the key is still pressed the system is notified that a valid input exists The program then jumps to a subroutine which acts on the key press 1 ON KEYPAD GOSUB tells the program where to branch when a key is pressed The syntax is ON KEY PAD GOSUB line label The line label is the beginning of the subroutine to react to the key press The routine must end with a RETURN statement If the line label are omitted this task is disabled Event Multitasking 8 2y KEYPA D function returns either a one character string that has been assigned to each key or the numerical position of the key The two variations are AS KEYPADS 0 returns a string character to a string variable The assignment is shown below A null string is returned if no key was pressed This variation is most useful where a single character can be assigned to match the keypad marking A KEYPADS 1 returns the key position number to a numeric variable A zero is returned if no key was pressed For large keypads the legends often contain some words and symbols in addition to letters The variation is most suited for these cases Assigning Character String to Keys A table in RAM can be programmed to return any ASCII value The table is
65. T Status OK confirm CUR INP 12 IF CUR lt 2 THEN F 0 ELSE F 1 RETURN current _test RUNAMPS 1 5 AIN 2 RETURN gt FIND RUNAMPS Commands 48 ERROR 60 UNTIL RUNAMPS gt 5 310 RUNAMPS 1 5 AIN 2 gt FIND GOSUB 20 GOSUB confirm 50 GOSUB current_test gt FIND 200 confirm 300 current_test gt FIND confirm 200 confirm 210 CUR INP 12 220 IF CUR lt 2 THEN F 0 ELSE F 1 gt FIND CUR 80 COR INP 35 90 IF COR lt 176 THEN PRINT Status OK 210 CUR INP 12 220 IF CUR lt 2 THEN F 0 ELSE F 1 In this case you would be able to detect the conflict between the COR and CUR variables lt Syntax gt for other argument variations Commands 49 SYNTAX PURPOSE REMARKS EXAMPLE ERROR FOR NEXT STEP Statements FOR variable n TO m STEP z NEXT To perform a loop operation a given number of times n and m are positive including zero numbers and the optional z may be negative or positive but not 0 n is the initial value of the counter m is the final value of the counter The program lines following the FOR statement are executed until the NEXT statement is encountered Then the counter is incremented by the amount specified by the STEP value z If z is not specified the increment is assumed to be 1 one A check is performed to see if the value of the counter is now greater than the final value m If itis not gre
66. XAMPLE ERROR CLS Statement CLS n To clear the screen of a terminal connected to a serial port using PC SmartLINK This statement sends a string of control characters lt ESC gt out the serial port n legal serial port number When n is not present the COM 1 port is cleared 200 CLS lt Datanegative gt forn lt Data out of range gt ifn is not a legal port number Commands 21 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR COMS Process Function n COM n To return a string from the serial input buffer This function is usually used in conjunction with ON COMS n legal serial port number 1 or 2 COMS returns the characters in the buffer up to the terminating character if specified or the total number of characters in the buffer When COM is executed the characters in the buffer are removed Immediately executing COM again will produce a null string RPC 2350 NOTE The CAM BASIC statement BIT 128 4 0 may need to be executed before you will receive any characters This command enables the CTS line to the sender CLEAR COM ON COM CONFIG COM See the ON COM statement lt Datanegative gt forn lt Illegal argument gt ifn is not a legal serial port number Commands 22 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR CONFIG Statement CONFIG command list The CONFIG statement is used to set parameters fo
67. able gt if card does not support user serial EEPROM lt Data negative gt for address lt Data gt 65 535 gt for address Commands 113 lt 21 gt lt Hardware gt If Flash EPROM or jumper missing or bad Flash Commands 114 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR n SGN n Determines if number is positive or negative m is any number SGN returns the following n 0 mis 0 n 1 m is positive n 1 m is negative none 10 A 15 20 PRINT SGN A RUN none Commands 115 SGN Numeric Function SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR n SIN m To calculate the trigonometric sine function SIN Numeric Function m is an angle in radians To convert degrees to radians multiply by PI 180 where PI 3 141593 ATN COS TAN PRINT SIN 1 5 997495 none Commands 116 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR SOUND COMMAND SOUND frequency SOUND Generates a square wave signal at frequency frequency is from about 8 Hz to about 60 KHZ depending upon the system Using SOUND with out any parameters turns it off The frequency argument is used in a CPU timer For the RPC 150 and RPC 2300 the clock is 230 4 KHz For the RPC 2350 it is 460 8 KHz If frequency is an exact multiple of this number the output will be accurate For any frequency the actual frequency is calculated as follows Anex
68. able table Put the variables which need to execute fastest at the beginning 10 A 0 B 0 C 0 AS 2 Use constants rather than variables whenever possible in all functions and statements Except for the pre compiled variables above a lookup time is required POKE amp 9000 4 fastest POKE A B fast POKE A B slowest 3 The speed of execution is independent of the length of the variable name 4 Place several statements on the same line This will yield a slight increase in speed at the expense of clarity 5 Use INC and DEC whenever possible They are much faster than the standard syntax to increment variables INC A fastest INC A fast A A 1 slowest 6 All string operations are slow This is especially true when concatenating strings When printing avoid string concatenation PRINT AS BS fast PRINT AS BS slow 7 Certain mathematical operations have long execution times multiply divide SIN COS ATN SQR LOG EXP and 8 Replace a list of conditionals with the ON GOTO statem ent 10 ON X GOTO 200 300 400 500 fast 10 IF X 1 GOTO 200 very slow 20 IF X 2 GOTO 300 30 IF X 3 GOTO 400 40 IF X 4 GOTO 500 9 Even though remarks are not executed there is a slight amount of overhead to skip over the list number You Program ing Tips 1 10 11 12 13 14 15 16 17 18 can use PC SmartLINK to strip out the remarks in the final program However this may have a significant impact on clarity
69. address bit preset AUTO To define the characteristics of a software counter The CONFIG COUNT statement is the initial step in setting up a software counter Up to eight counters can be defined A counter input may be any digital input The counter number has a range of 0 to 7 The address is the address of a parallel I O port The bit parameter specifies bit 0 through 7 of that port The optional preset parameter is only used when you want an interrupt at a specified number of counts When the optional AUTO parameter is specified the counter will automatically reset to zero when the preset is reached For additional information see the Multitasking Chapters ON COUNT START COUNT STOP COUNT RESUME COUNT 10 CONFIG COUNT 4 32 2 5000 This configures counter 4 at address 32 and bit 2 with a preset count of 5000 lt Data negative gt for number address bit preset lt Data gt 65 535 gt for preset and address lt Data out of range gt if number or bit gt 7 CONFIG Commands 7 SYNTAX PURPOSE REMARKS RELATED CONFIG DISPLAY address type cursor To install a driver for a display CONFIG DISPLAY Statement CAMBASIC supports eight vacuum fluorescent DP series and liquid crystal LCD displays When the CON FIG DISPLAY statement is executed a driver is installed that tells CAM BASIC the I O address type and cursor The address is the address of the output port at which the displa
70. am Small programs can be stored in DATA statements and POKEd into memory Other features include a Line renumber ing b 48 error messages to pinpoint problem areas c Access to system information d Bit BCD byte word and floating point data supported e Hex input and hex and binary output supported Introduction 3 Getting Started To program in CAMBASIC you will need aterminal to interface with your CPU card This may be aCRT terminal or a PC configured as a terminal If you use the PC you will need additional software for your PC to communicate SmartLINK turns your PC into a program development workstation See your hardware manual for setup instructions You should review the CAM BASIC commands in Chapter 4 of this manual Don t be overwhelmed by the number of commands available Most programs use only a limited number of commands You will find that most com mands in CAMBASIC are familiar to you if you have ever programmed in any basic before On power up a message is printed like that below If a nonsense message appears your terminal is not set at 19 200 baud one start bit 8 data bits one stop bit and no parity The amount of free memory is product dependent CAMBASIC TM Version 1 00 1985 93 Octagon Systems Corp 1994 Remote Processing Corp All rights reserved Free 30482 gt The underline _ shown to the right of the gt prompt represents the cursor position Y our cursor may be a block
71. ample frequency of 1000Hz on the RPC 2350 is used 1 Internal clock 230 4 KHz or 468 8 KHz desire frequency ratio 468800 1000 468 8 2 Round the ratio 468 8 becomes 469 3 Actual frequency is determined Internal clock ratio Actual frequency 468800 469 999 6 NOTE The RPC 2350 uses the same timer as SOUND for RS 485 communications You cannot use RS 485 at the same time as SOUND none 10 SOUND 1000 lt Data neg gt if frequencyis lt 0 No error occurs when frequency gt 65 535 but output is not correct Commands 117 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR SPI FUNCTION a SPlI channel out_length data delay in_length Where channel 0 to2 the SPI channel number out length 0 to 16 data output length in bits When zero no data is shifted out data can be any value but must be included data 0 to 65 535 command data to send to SPI device delay time to wait before retrieving information from SPI port after the last bit is shifted out Time in micro seconds is calculated as follows time delay 1 1 4 If 0 there is no delay Use 0 if there is no data to retrieve i e sending to D A in_length 0 to 16 data input length in bits Will return a number from 0 to 65535 Writes to and receives data from SPI port This port is not on all boards Refer to hardware manual SPI Serial Peripheral Interface is used to communicate with a number of IC s The
72. and runs it Disables interrupts at a critical time in a program Returns natural log of m Returns part of string m Inserts a string into a string Returns remainder of integer division Invokes the mini monitor Initializes for a new program Performs a negation Used with various statements Calculated branch to a subroutine Declares I O line to monitor logic level Branches program on CONFIG COM Executes subroutine on a preset count Enables error trapping Causes a break on an input pattern to subroutine Branches program on interrupt Branches program with keypad input Causes periodic program branching Read and write to OPTO racks Performs logical OR Sends a byte to an output address Returns byte from memory Returns string from memory Writes byte into memory location Sends string to memory address Outputs data Prints formatted strings or number Command Summary 4 Command PRINTS PULSE READ REMARK RENUM RESTORE RESUME RESUME line RESUME NEXT RESUME COUNT RETURN RETURN ITR n RIGHT RND RUN SAVE SGN SIN SOUND SPI SQR START BIT START COUNT START INP STOP STOP BIT STOP COUNT STOP INP STR SYS TAB TAN TICK Syntax PRINT char char n PULSE m PULSE n m b t p READ variable RENUM newline RESTORE line RESUME RESUME line RESUME NEXT RESUME COUNT m RETURN RETURN ITR 7n n RIGHT m p n RND m RUN line SAVEn n SGN m n SIN m SOUND frequenc
73. ater CAMBASIC branches back to the statement after the FOR statement and the process is repeated If it is greater execution continues with the statement following the NEXT statement This is a FOR NEXT loop If z is negative the test is reversed The counter is decremented each time through the loop and the loop is executed until the counter is less than the final value The body of the loop is executed once if is already greater than m when the STEP value is positive or if n is less than m when the STEP value is negative Ifz is zero an error will be displayed FOR NEXT loops may be nested that is one FOR NEXT loop may be placed inside another FOR NEXT loop When loops are nested each loop must have a unique variable name as its counter The NEXT statement for the inside loop must appear before the NEXT for the outside loop 10 J 10 K 30 20 FOR I 1 TO J STEP 2 30 PRINT I 40 K K 10 50 PRINT K 60 NEXT 1 40 3 50 5 60 7 70 9 80 lt NEXT w o FOR gt if a NEXT is encountered without a corresponding FOR lt Data out of range gt ifz 0 Commands 50 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR FPEEK and FPOKE Memory Function and Statement a FPEEK address a FPEEK address segment FPOKE address data FPOKE address data segment FPEEK returns a floating point number previously stored in memory FPOKE writes a floating point number to memory This function can be used t
74. ax above may be different for your card lt Data negative gt echo port lt Data gt 255 gt echo port Commands 64 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR INSTR Function a INSTR string substring Returns the position of the first occurrence on a sub string within a string The parameter n specifies where the search is to start in the string A 1 signifies the leftmost position in the string This parameter is not optional Its range is 1 to 252 string is a string constant or string variable that is to be searched substring is the string variable or constant to be searched for If n is greater than the length of string or if string is null or if substring cannot be found INSTR returns zero If substring is null INSTR returns n or one LEFT RIGHT LEN and MID 10 A BOOHOO 20 BS HOO 30 PRINT INSTR 1 A B RUN 4 lt Illegal argument gt ifn lt 1 Commands 65 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR INT Numeric Function a INT b To return an integer that is equal to or less than the argument 6 The integer portion is stored in variable a as a floating point number MOD integer divide PRINT INT 45 67 45 PRINT INT 15 02 16 To produce true rounding to the closest whole number use the following syntax A INT B 0 5 Adding 0 5 provides the true rounding and emulates the CINT function fo
75. c Function n BIN m To return anumber from a packed BCD number This function assumes that the BCD digits are packed That is there are four BCD digits per 16 bits A BIN B Normally the only way BCD data can enter the system is through an I O port like those on the 82C55 e g reading a two digit BCD thumb wheel switch Each of the two switches has four outputs Together the eight lines are connected to an I O port input Assuming the thumb wheel switches are set to 98 and connected to I O port amp 18 the port input would look as follows where DO through D7 are the eight data bits D7 D6 D5 D4 D3 D2 DI DO 1 0 0 1 1 0 0 0 The example below appears wrong at first However CAMBASIC assumed that this was a binary number and gave you the decimal equivalent PRINT INP amp 18 152 To get the correct result PRINT BIN INP amp 18 98 lt Illegal argument gt if any BCD digit gt 9 lt Data negative gt form Commands 9 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR BINS String Function n BIN m Returns an 8 bit binary representation of a number The most significant bit bit 7 is on the left and the least significant is on the right If a string argument is inadvertently used the result will be zero This function is primarily used with the INP function to display the status of each input line The HEX function and the binary prefix PRINT BINS 199
76. can be used in expressions and in any CAMBASIC statement or function that uses variables Declaring the name and type of an array and setting the number of elements and their arrangement in the array is known as defining or dimensioning the array Usually this is done using the DIM statement For example 10 DIM G 100 This creates a one dimensional string array named G All its elements are variable length strings The elements are assigned an initial value of null empty zero length 10 DIM TEMP 20 20 This creates a two dimensional array named TEMP All the array elements have an initial value of zero Each array element is named with the array name subscripted with a number or numbers An array variable name has as many subscripts as there are dimensions in the array The subscript indicates the position of the element in the array Zero 0 is the lowest position The maximum number of dimensions for an array is 255 The maximum number of elements per dimension is 32 767 but available system memory will prevent reaching this limit Arrays have a default dimension of 10 This gives a total of 11 elements 0 through 10 Constants Constants are literal values These are known values as opposed to variables which can be assigned any value Constants may be numeric or string A string constant literal string is a sequence of characters enclosed in double quotation marks Examples of string constants are Power Valve
77. ctangular area DISPLAY F X x1l y1 x2 y2 Toggles or XORs a rectangular area DISPLAY P x y Turns on a point at x y DISPLAY LINE x1 y1 x2 y2 Draws a line from xl yl to x2 y2 DISPLAY OFF type Turns display off type is C or G DISPLAY ON type Turns display on type is C or G Some boards have additional commands and XY limits Refer to your hardware manual for these limits xl yl and x2 y2 specify the coordinate points for a command DISPLAY LINE draws line on a graphics display Its syntax is DISPLAY LINE xl y1 x2 y2 Where x1 x2 0 to 159 LCD 5003 on RPC 30 yl y2 0 to 127 LCD 5003 on RP C 30 The P parameter puts a single point to a graphics display Commands 35 RELATED EXAMPLE A point is erased using the CLEAR DISPLAY P x y command Graphics dots in a line are cleared using the CLEAR DISPLAY LINE command ON enables character graphics or both displays Power on default is both graphics and character display ON Turning on or off the character or graphics does not affect the other In other words you could turn characters on without affecting the graphics display It is possible to update the graphics and character screen even if they are off Large Character Commands Some versions of CAM BASIC print larger characters These characters are drawn as graphics DISPLAY M x y text Print medium size characters DISPLAY M R x y text Print medium size characters in reverse color format D
78. cter 10 CVS CHR 27 A 12 20 MID CV 3 23 30 PRINT CVS ESC A23 lt Data negative gt fors and n lt Data out of range gt ifs 0 lt Data gt 255 gt forsandn Commands 78 MOD Operator SYNTAX n aMOD 5b PURPOSE To return the remainder of an integer division REMARKS a is divided by b and the remainder is placed in n The arguments a and b are first rounded to integers These must be in the range from 32 768 to 32 767 no error messages are given The division is then done and the quotient is truncated to an integer The sign of the result is always the sign ofa RELATED for integer division EXAMPLE PRINT 8 MOD 4 8 4 2 with 0 remainder 0 PRINT 5 MOD 3 5 3 1 with 2 remainder 2 PRINT 7 5 MOD 3 7 3 2 with 1 remainder 1 PRINT 7 5 MOD 3 8 3 2 with 2 remainder 2 ERROR lt Division by zero gt ifb is zero Commands 79 SYNTAX PURPOSE REMARKS EXAMPLE MON Command MON To invoke the Mini Monitor The Mini Monitor is used primarily for debugging object code programs Its use assumes that the program mer is familiar with assembly code and debugging techniques Unlike CAMBASIC all data is entered in hexadecimal The Mini Monitor sub commands are D Display memory E Edit memory F Filla block of memory M Math add subtract multiply in Hex Q Quit Mini Monitor See the Mini Monitor Chapter for more inform ation MON
79. curs when the bit pattern is recognized The interrupt will occur on the first instance of the pattern match It will not interrupt again until the inputs change and then change back to match the pattern This is sometimes called an edge triggered mode The parameter n is the task number It ranges from 0 to 7 The address is the I O address of the port to be read The mask parameter determines which bits are of interest Each bit in the mask that is a 1 is a bit of interest When the data at the port matches the compare parameter an interrupt occurs and the program branches to the ine label Up to 8 conditions may be tested on the same port or different ports See the Multitasking Chapter for more information START INP STOP INP 10 ON INP 0 3 7 5 GOSUB 60 20 START INP 0 30 PRINT BINS INP 0 40 DELAY 25 50 GOTO 30 60 PRINT match 70 RETURN lt Data negative gt all parameters lt Data out of range gt if n gt 7 lt Data gt 255 gt for mask and compare lt Data gt 65 535 gt for address lt Can t compile gt if line label not found Commands 87 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERRORS ON ITR Tasking Statement ON ITR n GOSUB line label ON ITR n GOSUB To enable or disable a program branch due to an hardware interrupt Check your hardware manual to determine if this statement is active for your card It is not active for the RPC 2300 or
80. d line has a column range from 40 to 79 When more than 80 characters are written to the display in the sequential mode the display will wrap around back to the beginning If the display lines are 20 characters long a different mode is used The first row has a column range from 0 to 19 Columns 20 through 39 are not used Writing to these columns will not affect the display Columns 40 through 59 form the second display line and columns 60 through 79 are not used No display wrapping will occur from row 1 to row 2 This is true in both the sequential and random access modes DISPLAY functions like the PRINT 10 statement A carriage return line feed will be appended to the DISPLAY statement unless there is a trailing semicolon On LCD character displays this shows up as garbage characters Graphic Commands The LCD graphics display has several command Some or all of these commands are not available on all cards Refer to your hardware manual to determine if itis available CLEAR DISPLAY Clears graphics and characters from display CLEAR DISPLAY LINE Clears characters at current line CLEAR DISPLAY LINE xl yl x2 y2 Clears graphics line from xl yl to x2 y2 CLEAR DISPLAY P x y Clears a point on a graphics screen CLEAR DISPLAY C Clears all characters graphics not affected CLEAR DISPLAY G Clears all graphics characters not affected DISPLAY F x1 y1 x2 y2 Fills rectangular area xl yl to x2 y2 DISPLAY F C x1 y1 x2 y2 Clears a re
81. derline character and the period TIME_OUT MOTOR_ON START_PRE HEAT RELAY 1 The length of an array variable name is not used PUM P n and PP n are seen as the same variable and will return the same value The variables A through Z are pre compiled This gives them two special advantages not shared with the rest of the variables They are not cleared to zero on power up reset or when chaining programs They also execute about 50 faster in an average program NOTE Variables with as the second character may only be used for simple variables and not array or string variables There are simple array and string variables The is used when defining a string variable Different type variables may have the same name For example A A A A 0 Variables may contain keywords as long as the keyword is not first Keywords may be imbedded in variable names Concepts 6 For example GOTOE is not ok EGOTO is ok String variables are limited to 255 characters Arrays may be any length may be multidimensional and include strings String and array space is limited only by available memory Numeric variables take seven bytes of memory Two bytes for the name one byte for the length and four bytes for the value String variables are stored with a 7 byte header and byte for byte as the string was assigned The header and string are stored in different locations String Variables CAM BASI
82. dicates that the number contained digits outside the specified field A 1234 67 PRINT USING A 0 12E 4 In this case the first specifies the leading zero to the left of the decimal point PRINT USING A 1 23E 3 Commands 98 ERROR Leading zeros to the left of the first digit to the left of the decimal point are suppressed A 25 5555 PRINT 10 USING A 25 56 Note that true rounding to the second decimal place took place Output is to the LCD character or graphics display as defined in CONFIG DISPLAY PRINT 2 USING TICK 0 23 7850 Prints to COM2 port current tick time lt Illegal argument gt if the field specifier is longer than 8 characters lt Data out of range gt ifn is not a legal serial port number NOTE Illegal combinations of field declaration characters may cause erratic printing Commands 99 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR PRINTS Statement PRINT n character character R n character character Used to send any character from 0 to 255 out a serial port The statement is often used to send escape sequences to printers displays etc It is the same as PRINT CHR n CHR n CHR n n valid port number Port numbers are 1 and 2 for serial 9 for VF display 10 for LCD display LCD and VF displays must be configured using the CONFIG DISPLAY command before use T
83. dited a line at a time Since you are talking through a serial port to your PC or terminal full screen editing like that on your PC is not possible To insert a new line you just type the line and the CAMBASIC editor will place it in the proper numeric sequence with the rest of the program If there was previously a line with the same line number the previous line is deleted before the new line is added To delete a whole line type the line number and then lt ENTER gt Some commands are prefixed with n This is an optional numeric parameter For example 5D means delete the next 5 characters A Abort all changes and reenter Edit Mode on same line I Insert Mode active L Lists the entire line X Extend the line by moving cursor to end and enter Insert Mode H Hack off the remainder of the line and enter Insert Mode nD Delete n characters nM Delete n characters and enter Insert Mode nR Replace n characters n lt SPC gt Space n characters lt ESC gt Escapes the Insert Mode lt ENTER gt Save the edited line lt BKsp gt Nondestructive cursor backspacing All commands may be used within a single line Use of an illegal command causes the bell on the terminal to sound If an attempt is made to space beyond the actual line length the cursor will simply stop WARNING When using the screen editor in PC SmartLINK do not use the EDIT command Use LIST to put the lines you want to edit on the screen ENTERING THE EDIT
84. e by 0 will cause error A 30 B 10 A 40 GOTO 20 50 PRINT Error ERR occurred on line ERL 60 ON ERR GOTO 50 re enable error trapping 70 RESUME NEXT resume at next statement after error none Commands 43 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR ERR System Variable n ERR To return the error code associated with an error The function returns the error code for the last error It is usually used in conjunction with the ERL function Error trapping is essential in control applications where a halt in execution is not tolerable See the Error Messages Chapter for a list of error codes and messages ERL ON ERR RESUME ERR statement 10 ON ERR GOTO 50 enable error trapping 20 INPUT Enter a number to divide by 0 will cause error 30 B 10 A 40 GOTO 20 50 PRINT Error ERR occurred on line ERL 60 ON ERR GOTO 50 re enable error trapping 70 RESUME NEXT resume at next statement after error none Commands 44 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR ERROR System Statement ERR n To simulate the occurrence ofa runtime error This statement is usually used to test error trapping systems using the ERR and or ERL functions If n is not an assigned error number an unknown error message will result See the Error Messages Chapter for a list of error codes and messages ERL ERR function ON ERR RESUME
85. e edited LINE EDITING COMMANDS A Abort All Changes And Reenter The Edit Mode If you change your mind in the middle of an edit you can use the A command to cancel all the editing work done on the line so far and redisplay the command for further editing If you are in the Insert Mode when the decision to abandon the edit occurs you must exit the Insert Mode To get out of the Insert Mode press the lt ESC gt key then press lt A gt D Delete To delete a character move the cursor to the character to be deleted Note that the character is not printed at the cursor Now press the lt D gt ona terminal do not press lt ENTER gt yet If several characters are to be deleted press the number first and then the lt D gt key The cursor will move leaving blanks where the deleted characters are Now press lt ENTER gt The line is reprinted with the blanks indicating the edit The blanks are not stored in the text You can confirm this by executing gt LIST line CAMBASIC will not let you delete more characters than exist on a line There is no way to undo a delete except by performing an Abort lt A gt To view the changes to the line type lt L gt The entire line will be displayed ESC Escape From Insert And Replace Modes This command turns off the Insert Mode Ifyou wish to use other editing commands while in Insert Mode you must press lt ESC gt Program Editing 2 Hack Remainder Of The Line And Ent
86. e exponential function of e EXP Numeric Function This function returns the result of the number e 2 718282 raised to the power given by m 10 PRINT EXP 1 EXP 2 RUN 2 71828 lt Overflow gt 7 38906 if m gt 88 0296 Commands 47 SYNTAX PURPOSE REMARKS EXAMPLE FIND Command FIND argument Used to locate variables keywords and labels This is auseful tool especially in long programs The variations described below FIND keyword This will list all the lines that contain the specified command or function keyword For example FIND POKE FIND Lists all lines that start with labels It does not list lines where the label is part of a GOSUB etc Executing FIND GOSUB will listall instances of a GOSUB FIND label This will list the subroutine that begins with a specific label name FIND will continue to list every line until it encounters the label symbol or RETURN FIND variable Lists the line of every instance of the variable name It will help locate 10 20 30 40 50 60 70 80 90 200 210 220 230 240 300 310 320 330 conflicting variables For example PIT and PAT have the first and last letter and the same length If you execute FIND PIT then lines with PAT PET PIT POT and PUT are also listed MOTOR 1 GOSUB confirm PRINT Motor OK DO GOSUB current _test UNTIL RUNAMPS gt 5 OUT 35 43 COR INP 35 IF COR lt 176 THEN PRIN
87. e from 0 005 0 010 in 9 MHz systems to 327 67 655 35 in 9 MHz systems seconds Defining a Pulsed Output Setting up a timer is done with the PULSE statement The syntax is PULSE 2n address bit w ait time polarity Where n is the timer reference number and has a range from 0 to 7 address is the I O address of an any 8 bit port either on or off the card bit is the particular bit of the port The value ranges from 0 to 7 time is the time in seconds that the specified bit is active You may specify a time from 0 005 to 327 67 seconds polarity determines whether the specified bit will be active high or low When polarity is 1 the bit will go high during the active time It will go low during the active time if the polarity is 0 The 0 polarity is always used when driving opto module racks In the simplest mode operation with the polarity active high would be as follows ON OFF Figure 2 Faster Code Execution The data that you enter with the PULSE statement is compiled into object code Thus the execution time on the 200 Hz 100 Hz in 9 MHz systems clock tick is only microseconds rather than the milliseconds that it would take in BASIC Operation of a Single Pulsed Output Timer 0 is configured at address 0 and bit 1 The output will go high for 0 050 seconds as soon as the command is Event Multitasking 14 executed and then go low The PULSE function returns the remaining time of each stage The e
88. e input serial buffer you may bring them out one ata time Each time INKEY is executed a character is removed from the buffer The buffer is 255 characters RPC 2350 NOTE The CAM BASIC statement BIT 128 4 0 may need to be executed before you will receive any characters This command enables the CTS line to the sender COMS INPUT 10 A INKEY 1 20 IF A THEN 10 30 IF A Y THEN PRINT YES 40 IF A N THEN PRINT NO 50 GOTO 10 lt Illegal argument gt ifn is not a legal port number lt Datanegative gt forn Commands 59 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR INP I O Function n INP O address OUT I O address data INP returns a byte from an V O address OUT writes a byte to an O address I O address is in the range of 0 to 65 536 amp FF FF data is in the range of 0 to 255 amp FF INP and OUT are used to read and write to hardware devices such as digital I O and counters INP is the complementary function to the OUT statement WARNING SomelI O address are used internally and should not be written to with the OUT statement Generally these are from amp 80 to amp CF See your hardware manual for these addresses BIT 100 A INP 255 120 OUT amp 40 12 lt Datanegative gt for I O address and data lt Illegal argument gt if 1 O address gt 65 535 lt Data gt 255 gt ifdata gt 255 Commands 60 SYNTAX PURPOSE
89. e that it was interrupted It is imperative that the counter numbers in CONFIG COUNT and START count match Otherwise operation will be unpredictable Event Multitasking 5 NOTE It is theoretically possible for the subroutine to take so long to execute that another 2000 counts is reached In this unlikely case the subroutine will interrupt itself CAM BASIC is not recursive The effect of this is that the second interrupt may change variables that the first interrupt has yet to use This situation can be avoided by careful programming and by detailing the system timing It is always a good idea to keep interrupt routines as short as possible COUNT Examples You must do a CONFIG COUNT ON COUNT and START COUNT for each counter you intend to use You may reconfigure a counter to another address or to a different condition at any time as long as the counter has been disabled by CLEAR COUNT The example below lets you get a feel for the operation of the counter while at your desk You can create output pulses by pressing keys on your PC These pulses are then jumpered back into a counter The hardware requires a CM A 26 cable and a STB 26 Plug one end of the CM A 26 into the parallel port and the other end into the STB 26 Place a jumper wire between screw terminals x and y on the STB 26 Enter the following program 10 CONFIG PIO 0 0 1 0 1 1 20 CONFIG COUNT 4 0 1 30 ON TICK 0 1 GOSUB pr_count 40 START COUNT 4 50 INPUT AS 60
90. e too complicated to evaluate A nonexistent line number is referenced in an EDIT DELETE REN UM etc state ment An array element is referenced either with a subscript that is outside the dimensions of the array or with the wrong number of subscripts Two DIM statem ents are given for the same array or a DIM statement is given for an array after the default dimension of 11 has been established for that array A division by zero is encountered in an expression or the value zero has been raised to a negative power In the first case the result is machine infinity with the appropriate sign in the second case the result is positive machine infinity Error Messages 1 NUM 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 MESSAGE lt Illegal imm ediate gt lt Type mismatch gt lt Out of string space gt lt String too long gt lt String too complex gt lt Can t CONT gt lt UNTIL w o DO gt lt Data out of range gt lt DO F OR GO SUB stack gt lt Hardware gt lt System corruption gt lt Expected variable gt lt Can t compile gt lt RESUME w o ON ERR gt lt Data negative gt EXPLANATION A statement that is illegal in Immediate M ode is entered as an Immediate Mode command A string variable name is assigned a numeric value or vice versa a function that expects a numeric argument is given a string argument or vic
91. e versa String variables have caused CAMBASIC to exceed the amount of free memory remaining CAM BASIC will allocate string space dynamically until it runs out of memory An attempt is made to create a string in excess of 255 characters or a string is too long for command limits A string expression is too long or too complex to be processed It should be broken down into smaller expressions An attempt is made to continue a program that a Has been halted due to an error b Has been modified during a break in execution c Does not exist An UNTIL statement has been encountered withouta matching DO A parameter for a statement is outside the allowable range A GOSUB RETURN FOR NEXT and or DO UNTIL loops are nested too deep CAM BASIC is attempting to access an I O device which is not connected or is inoperative The card is trying to execute data rather than code This error trap can prevent some system crashes due to the modification of system RAM either inadvertently or through noise Only a variable may be used as the parameter or argum ent CAM BASIC cannot compile the line because a there are too many numeric constants b a nonexistent line number is referenced Cc a line or label is referenced that does not exist A RESUME was encountered without a corresponding ON ERR statement The argument or parameter may not be negative Error Messages 2 Error Messages 3 NUM 27 28 29 30
92. ed for all channels none 10 CONFIG AIN 0 0 1 Configures channel 0 for differential mode 0 to 5V on the RP C 2350 lt Data negative gt all parameters lt Data out of range gt if illegal parameters CONFIG Commands 1 SYNTAX PURPOSE REMARKS CONFIG BAUD Statement CONFIG BAUD port baud rate mode parity com To change the serial port parameters The power up default for COM1 is 19 200 baud 8 data bits and 2 stop bits no parity The power up default for COM2 is 19 200 baud 8 data bits and 1 stop bit no parity RS 232 All these parameters are programmable Once programmed the serial parameters will remain in place even when the program stops A reset or another power up will cause the default values to be reinstalled port is the COM port number COM1 is 1 COM2 is 2 The baud rate parameter is a number from 0 to 7 or 8 which correspond to the baud rates below 0 150 4 2400 8 38 400 RP C 2350 only 1 300 5 4800 2 600 6 9600 3 1200 7 19 200 The mode parameter determines the data word length whether parity is checked and the number of stop bits 0 7 data no parity 1 stop 4 8 data no parity 1 stop 1 7 data no parity 2 stop 5 8 data no parity 2 stop 2 7 data parity 1 stop 6 8 data parity 1 stop 3 7 data parity 2 stop 7 8 data parity 2 stop The parity parameter determines the type of parity Specifying a 0 is even parity and specifying 1 i
93. ement Thus the hardware interrupt is converted to a software interrupt At the hardware level the interrupts are prioritized However the software response to the interrupts have equal priority Any interrupt can preempt any other interrupt Software Interrupts CAMBASIC has other interrupts which are purely software interrupts For example you can cause program execution to branch on a periodic basis using the ON TICK statem ent All software interrupts have equal priority Any software interrupt can interrupt another software interrupt but not a hardware interrupt In the case of several nearly simultaneous interrupts the following sequence will occur Suppose the first interrupt service routine starts to execute only to be interrupted by a second interrupt If another interrupt occurs before the second routine finishes then the third interrupt routine will execute to completion Then the second interrupt service routine will finish followed by the first The software interrupts include 8 Port status interrupts ON INP 8 Input line interrupts ON BIT 2 Serial input interru pts ON COM 8 Counter interrupts ON COUNT 1 Keypad interrupt ON KEYPAD 3 Periodic interrupts ON TICK Assembly Language Interface You may call an assembly or a compiled language using the CAMBASIC CALL statement The compiled C or assembly language is object code which executes directly This code is generated by your linker on
94. ependent pulse output The lines may be on any digital I O port This command allows you to pulse a line for a period of time while executing other BASIC commands n is a pulse reference number and has a range from 0 to 7 This number is used for CLEAR PULSE and PULSE functions to reference this pulse timer The address is the I O address of an 8 bit port The range is 0 to 65535 amp FFFF The bit parameter is the particular bit of the port The value ranges from 0 to 7 The time parameter is the time in seconds that the specified bitis active You may specify a time from 0 005 to 327 67 seconds The polarity parameter determines whether the specified bit is active high or low When polarity is 1 the bit goes high during the active time If the polarity is 0 it goes low during the active time For more information see the Multitasking Chapter CLEAR PULSE PULSE function PULSE 5 0 2 2 55 1 Pulse number 5 is configured to output bit 2 at address 0 so the bit will go high for 2 55 seconds and then return low This sequence will execute only once lt Data gt 255 gt for address lt Data negative gt for n address bit wait active lt Time gt 327 67 sec gt for t lt Data gt 65 535 gt for address lt Data out of range gt if bit or bit gt 7 Commands 102 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR READ Statement READ variable variable To read
95. er Insert The Hack command deletes from the cursor position to the end of the line and enters the Insert Mode EDIT 10 10 PRINT This is PRINT a simple edit 10 Move the cursor to the e in edit 10 PRINT This is PRINT a simple edit 10 PRINT This is PRINT a simple _ Now type lt H gt and then the phrase hack and finally lt ENTER gt 10 PRINT This is PRINT a simple hack Insert The lt I gt key is used for insert The cursor is normally a blinking underline character When in the Insert Mode this changes to a blinking block character When using a CRT terminal lt I gt turns on the Insert Mode and lt ESC gt turns it off After the Insert Mode is turned off you can continue editing the remainder of the line Typing an lt ENTER gt when in the Insert Mode will cause the edited line to be saved List The Entire Line Use the L command to finish listing the line and remain in the Edit Mode This command is useful when you have made several inserts and deletions in a line Modify By Deleting And Inserting The Modify command deletes n characters and enters the Insert Mode It is a combination of the Delete and Insert Modes EDIT 10 10 PRINT This is PRINT a simple edit 10 Space the cursor out to the I in is 10 PRINT This is PRINT a simple edit 10 PRINT This _ Now type lt 2M gt and the word was followed with lt ENTER gt The word is wa
96. f a binary 1 in either operand For example Operand 1 0001 0111 23 Operand 2 0100 1010 74 Operand 1 0101 1111 95 OR Operand 2 The AND operator detects the coincidence of two binary 1 s Operand 1 0001 0111 23 Operand 2 0100 1010 74 Operand 1 0000 0010 2 Concepts 10 AND Operand 2 Concepts 11 The NOT operator performs a logical negative of a value Operand 1 0001 0111 23 NOT Operand 1 1110 1000 232 Value of expression Value of NOT expression 1 2 2 3 2 1 1 0 NOTE The NOT expression is false only if the expression evaluates to a value of 1 If you define Boolean constants or variables for use in your programs use 1 for true The XOR operator essentially detects the presence of a binary 1 in either operand For example Operand 1 0001 0111 23 Operand 2 0100 1010 74 Operand 1 0101 1101 7 93 XOR Operand 2 Expression Evaluation Parenthesis The usual rules for order are followed in evaluating expressions The order of evaluation is controlled by parentheses Their liberal use is recommended both for error free code and for clarity They are required when mixing functional mathematical logical or relational operators Spaces CAM BASIC has a very forgiving attitude towards the use of spaces They may be used almost anywhere They must be used after keywords If the keyword is followed by a variable for example PRINTF will give a syntax error All spaces are
97. f one second The date string may be a variable or a constant In either case the format is the same The string must be in one of the forms below mm dd yy mm dd yy dw where mm is the month and ranges from 01 to 12 dd is the day 01 31 yy is the year 00 99 and dw is the day of the week 0 6 The RP C 2350 does not support dw or day of week DATES function and TIME 10 DATES 11 01 91 10 A 01 15 91 20 DATES A 10 A 04 02 99 4 20 DATES A lt Syntax gt if two digits are not used mm dd yy or if digits not 0 9 are entered lt Data out of range gt when month day and year are out of range or not numbers Extensive range checking is not performed You can enter 02 39 99 as a valid date Range checking on RPC 2350 series only Commands 28 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR DATE System Function a DATE n The DATES function is used read the date of the system calendar clock The system clock keeps time on a 24 hour basis with a resolution of one second The date is returned in two forms depending upon the value of the argument n When n 0 the months days and years are returned When n 1 the day of the week is returned The RPC 2350 does not support day of week The clock is set by the DATE statement DATES statement and TIME 10 DATES 02 11 91 4 20 PRINT DATES 0 30 PRINT DATES 1 02 11 91 04 lt Datanegative
98. grams and data to flash EPROM Some cards such as the RPC 150 and RP C 2300 only allow the first SAVE syntax Cards with 128K or more of flash EPROM allow saving more than 1 program These same cards also allow saving binary data Refer to your hardware manual to see if it supports 128K of flash The RPC 150 and RPC 2300 do not The RPC 2350 does program is 0 or 1 when using a 128K Flash 0 7 when using a 512K Flash Both RAM and Flash address are in the range of 0 to amp FF FF 65535 Flash segment is from 8 to 15 Memory segments 0 7 are RAM while 8 15 are for Flash Segments may be limited depending upon the amount of memory installed RAM segment is 0 or 1 with 128K RAM installed and 0 7 with 512K RAM A simple SAVE transfers a program from RAM to Flash It begins saving at Flash address 0 SAVE program allows you to save programs as 0 or 1 using a 128K Flash or as 0 7 using a512K program and Flash segment are related by the following formula Flash segment program 8 Be careful when saving data It is possible to clobber a program by accessing the same location SAVE allows you to store information POKE d into RAM Data should be saved above where the program is stored to prevent clobbering The 3rd syntax can be executed during run time Use LOAD to transfer blocks of memory from Flash to RAM or RAM to RAM SAVE SAVE 1 Saves a program to Flash segment 1 SAVE 9 SA 1 RA 5500 Saves data to Flash lt Command not avail
99. gt 65 535 gt for address CONFIG Commands 9 RETURN SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR CONFIG PIO Statement CONFIG PIO init port A port B port LC port UC address To initialize an 82C55 parallel I O IC The 82C 55 parallel I O IC has four I O ports Each port can be programmed as input or output They are defined as follows Port A 8 bits 0 to 7 Port B 8 bits 0 to 7 Port LC 4 bits 0 to 3 Port UC 4 bits 4to7 The init parameter is the value you want output ports to be after the command is executed The 82C55 initializes itself to all inputs on power up When an input port is changed to an output port the 82C55 forces all the bits to a low state When it drives devices such as opto isolator modules this would be undesirable as all the modules would turn on Specifying 1 will make the ports go high specifying 0 will make the outputs go low The inputs will be unaffected PortA UC are direction parameters and are specified as 1 for an input port and 0 as an output port The address parameter is the base address of the chip You normally do not specify an address since CAMBASIC will use the default of 0 none 10 CONFIG PIO 1 0 0 1 1 This configures an 82C55 at the address default to have ports A and B as outputs Ports UC and LC are inputs Ports A and B will have high outputs lt Data negative gt for address init port directions lt
100. h your Systems card When you call please have the following at hand Your CAMBASIC Program ming Guide A description of your problem TEL 303 690 1588 FAX 303 690 1875 Preface 2 ABOUT CAMBASIC CAMBASIC is the result of 18 years of industrial language development at Octagon Its major strengths are ease of use unequaled performance and the rich vocabulary of industrial BASIC commands This version was adapted for Remote Processing Corporation CAMBASIC is a real time multitasking language for control and data acquisition applications It programs easily and has most of the BASIC language commands found on personal computers However the performance and the industrial extensions set CAMBASIC apart from any other BASIC dialect While all the commands and structures in this manual have examples of their use this manual is not intended to teach you how to program in BASIC We assume that you have at least some familiarity with BASIC or some other high level language If you have not had any program ming experience there are literally dozens of books that can teach you to program in BASIC Knowledge of electronics and or digital circuitry is not required to write successful programs Major Features In addition to the commands and features in BASICs like those found in personal computers CAMBASIC has some important extensions for industrial control data acquisition and ease of use 1 Labels Supported You can cal
101. han standard variables Event Multitasking CAMBASIC provides several types of multitasking All defined tasks operate in the background and are checked 200 times per second on 18 MHz systems and 100 times per second on 9 M Hz systems This includes periodic interrupts counting timed outputs checking the keypad input checking input combinations and checking inputs for a change of state Individual Bit Manipulation Most industrial control is done on a line or bit basis rather than an 8 line port basis CAM BASIC can set and reset individual bits without affecting other bits on the port It can also cause individual bits to be timed outputs that time out independently of program execution Automatic Serial Data Capture In many applications your microcomputer card may be connected to a host computer either through a modem or radio link or directly The computer can transmit a message to the microcomputer card while the card is executing a program An automatic interrupt can be generated when the message is completed or CAMBASIC can interrogate the message at its convenience Input and output characters are always buffered automatically Multi dimension Numeric and String Arrays Both numeric and string arrays may have up to 255 dimensions Error Handling In most applications it is important that program execution not be broken when a run time error occurs CAMBASIC can trap these errors and corrective action can be taken without stopp
102. haracters from m beginning with the pth character equal to zero or p is greater than the length of m then MID returns a null string If q is omitted then a string from position p to the end of m is returned LEFT LEN RIGHTS INSTR MID Statement 10 A ABCDEFG 20 PRINT MID AS 5 2 RUN EF lt Illegal argument gt ifp or q is out of range lt Illegal argument gt ifp 0 lt Datanegative gt forporq Commands 77 If q is SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR MID String Statement MID a s n b To replace a portion of one string with another A common usage for the MID statement is in networking protocols The network commands are standard strings defined by string variables Using the MID statement to modify these strings is much faster than other string methods The string a is the target string while b is the replacement string The parameter s is the starting point within a where b will be inserted The optional parameter n indicates how many characters of b are to be used When n is omitted all of b is used If b is longer than a replacement will not exceed the length of a No error message will be given LEFT LEN RIGHTS INSTR MID Function 10 FS Hopeless 20 R Help 30 MIDS FS 1 R 40 PRINT FS Helpless The example below is for a communications protocol Note that the escape character is not a printable chara
103. he string The CHR function is the inverse of the ASC function and is used to convert from the ASCII code to acharacter CHR STR VAL 10 FS Alert 20 PRINT ASC FS RUN 65 lt Illegal argument gt if m is a null Commands 5 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR ATN Numeric Function n ATN m To return the arctangent of m The result n of the ATN function is a value in radians in the range of PI 2 to PI 2 where PI 3 141593 The expression may be integer but the evaluation is always performed in floating point To obtain the tangent of m when m is in degrees use TAN m x180 Trigonometric functions are computed as a power series in CAMBASIC Calculations are done in single precision floating point to seven digits of precision Since the power series is an approximation the result will be accurate to four to six digits depending upon the value ofm COS SIN TAN 10 PI 3 141593 20 RADIANS ATN 1 30 DEGREES RADIANS 180 PI 40 PRINT RADIANS DEGREES RUN 785398 45 none Commands 6 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR AUTO COMMAND AUTO line increment Generate a line number automatically each time you press lt Enter gt after a program line AUTO is used for entering programs especially when downloading those without line numbers Num bering begins at line and increments each subsequent line by i
104. he syntax below displays the current line for editing The current line is the last line entered OR the last line edited OR the last line executed OR the last line in a download OR the line in which an error occurred whichever was the last condition lt ENTER gt 10 A 15 10 _ See the Editing Programs Chapter for more information NOTE Labels cannot be used in place of line number with EDIT NOTE PC SmartLINK has a screen editor which may also be used WARNING You cannot use EDIT when using the full screen editor in PC SmartL INK at the same time none lt Line label not found gt if line does not exist Commands 41 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR END To halt execution of a program at a given point END causes execution to cease without any message STOP 10 GOSUB 50 20 PRINT 30 END 50 PRINT 60 RETURN STATEMENT END END Statement Without the END statement at line 30 execution would continue through lines 50 and 60 with a second end printed A GOSUB error would also occur none Commands 42 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR ERL System Variable n ERL To return the line number associated with an error The function returns the line number of the last error encountered by CAMBASIC ERR ON ERR RESUME 10 20 ON ERR GOTO 50 enable error trapping INPUT Enter a number to divid
105. he valid character values are number prints numbers as a character string print the string constant within the quotes You cannot use string variables NOTE Due to compiler limitations the number of numeric parameters following the PRINT may not exceed 24 PRINT PRINT USING 10 PRINTS 27 71 33 END replaces 10 PRINT CHR 27 CHR 71 CHR 33 END 10 PRINT 2 27 72 33 Prints to COM 2 port lt Data negative gt for character lt Data gt 255 gt for character lt Data out of range gt ifn is not a valid serial port number Commands 100 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR PULSE Process Function n PULSE m To return the remaining time of a pulsed output The resolution of the software pulse timers is 0 005 seconds 0 01 sec in 9 Mhz systems The remaining time is returned in seconds A time of 0 indicates the PULSE command finished The argument range for m is 0 to 7 which is the pulse number set by the PULSE command See the Multitasking Chapter for more information CLEAR PULSE PULSE command 10 A PULSE 2 lt Datanegative gt form lt Illegal argument gt ifm gt 7 Commands 101 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR PULSE Tasking Statement PULSE n address bit tim e p olarity To configure a digital output line as a timed or pulsed output You may configure up to eight digital I O lines as ind
106. ified n is the source number For example 2 is COM2 If the is omitted the default is COMI Be careful when using this statement on boards with a watchdog timer Unless the input is already there in the serial buffer or the external device is quick the watchdog is likely to reset Also multi tasking routines such as ON TICK ON INP are not executed while INPUT is active RPC 2350 NOTE The CAM BASIC statement BIT 128 4 0 may need to be executed before you will receive any characters This command enables the CTS line to the sender none 10 INPUT Input pH volume PH VO RUN Input pH volume _ none Commands 61 Commands 62 SYNTAX PURPOSE REMARKS RELATED INPUT KEYPAD Statement INPUT KEYP AD echo port variable INPUT KEYP AD echo port text variable INPUT KEYP AD echo port text variable To input data from a keypad Optionally print text to echo port The INPUT KEYP AD statement is similar to the INPUT statement in that the program pauses to accept data from a matrix keypad The echo port parameter tells the system where to echo the keys pressed on the keypad The display must be previously initialized for an echo 0 no echo 1 COMI 2 COM2 3 7 no echo 8 Graphics display RPC 2350 only no echo on others 9 DP display 10 LCD display 11 speaker 12 255 no echo The INPUT KEYP AD statement terminates when a carriage return lt CR gt is received One of the keypad
107. ill branch when 8 characters have been received The XON and XOFF protocol functions are disabled via CONFIG COM statement All characters will be echoed lt Data negative gt n lt Data out of range gt ifn is not a legal serial port number lt Can t compile gt if line label does not exist Commands 84 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR ON COUNT Tasking Statement ON COUNT n GOSUB line label ON COUNT n GOSUB To execute a subroutine when a preset count is reached To use this statement you must first set up a counter with CONFIG COUNT and specify a preset count Every time the preset count is reached the counter is reset to zero and program flow branches to the routine specified by line When the subroutine is finished the program will resume execution If the line is not specified after the GOSU B the function is disabled The parameter n is the counter number which ranges from 0 to 7 See the Multitasking Chapter for more information CLEAR COUNT COUNT START COUNT STOP COUNT RESUME COUNT 10 CONFIG PIO 0 1 1 1 1 SET FOR INPUTS 20 CONFIG COUNT 0 0 0 500 AUTO 30 ON COUNT 0 GOSUB 60 35 START COUNT 0 40 50 GOTO 40 60 PRINT limit reached 70 RETURN lt Data negative gt forn lt Data out of range gt n gt 7 lt Can t compile gt if line label does not exist Commands 85 SYNTAX PURPOSE REMARKS RELATED EXAMPLE
108. ing program does an instant branch to one of 16 routines based on the position number 10 Branch on the Key Position 40 ON KEYPAD GOSUB Key interrupt 50 GOTO 50 60 Key interrupt 70 K KEYPADS 1 80 ON K GOTO 100 200 300 400 1600 90 RETURN 100 service key position 1 150 RETURN 200 service key position 2 250 RETURN and so forth Line 40 tells CAMBASIC to call a subroutine by the name of Keypad_interrupt every time a key is pressed Line 50 is used only as part of this demo program so that the system will wait You could insert the rest of your control program Line 70 assigns the input position to variable K Line 90 returns program execution to the place that was executing before the key was pressed However the program should never get to this point if 16 line numbers are specified Line 100 would be the routine to handle the operation desired by pressing key 1 Line 150 returns program execution to the place that it was executing before the key was pressed Line 200 would be the routine to handle the operation desired by pressing key 1 Line 250 returns program execution to the place that it was executing before the key was pressed Using INPUT KEYPAD The previous examples have shown how to use a keypad on an interrupt basis In some applications it is acceptable for the program to wait for operator input INPUT KEYPAD will accept data in the same manner as the INPUT statement does from a serial
109. ing the program Keypad and Display Support The DISPLAY and KEYPAD commands fully support RPC keypads and displays Large Programs Supported You can run programs as large as 32K in all cards Automatic Type Conversion In CAMBASIC you never need to declare integer or floating point variables C AM BASIC converts automatically as needed by the program Data is always stored as floating point so no precision is lost EEPROM Programming Supported CAM BASIC programs are developed in the on card RAM Once you are satisfied with its operation you type SAVE and an autorun EEPROM is programmed automatically Your program then runs from the EEPROM on power up Introduction 2 13 14 15 16 Process Functions Simplify Programming Most functions return the result of a numeric or string calculation A process function manipulates and acquires data from a hardware device For example the AIN function causes the A D converter to begin its conversion When the converter has finished the data is read and converted to the appropriate format Trace and Debug C apability The TRON and TROFF statements can be invoked to print out line numbers as the lines are executed Assembly Code and Compiled C Programs From BASIC Assembly code and compiled C programs may be combined with CAM BASIC programs The machine code segments are executed with the CALL statement You can pass up to 20 parameters to the machine code progr
110. intable or not may be used in a string The following characters have special significance in CAMBASIC Space or Blank Equals sign or assignment symbol Plus sign for addition or string concatenation Ea Minus sign for subtraction Asterisk or multiplication symbol Slash or division symbol Caret Control Key or exponent Left par enthesis Right parenthesis Left bracket Right bracket Percent or PRINT USING overflow indicator Binary number prefix or logical unit declaration Dollar sign or string declaration Comma and print separation symbol Period or decimal point Semicolon or carriage return suppressor Colon or program line statement delimiter lt Less than gt Greater than and system prom pt amp Ampersand or hexadecimal number prefix Binary num ber pr efix lt BKSP gt Backspace and erase the previous character lt ESC gt Escape input mode or halt execution Back slash and integer divider lt C gt Control C to break an INPUT statement lt S gt Control S is XON code lt Q gt Control Q is XOFF code des Two periods or label prefix lt ENTER gt Carriage return lt SPC gt Space Apostrophe or remark Concepts 3 Below isa list of CAMBASIC commands manual for exceptions if any ABS AIN AND AOT ASC ATN AUTO BCD BIN BIN BIT CALL CHR CLEAR CLS COM CONFIG CONT COS COUNT DATA DATE DEC DECF DEL DELAY DIM DISPLAY DO DPEEK DPOKE EDIT
111. ith the same m number it will produce the same sequence of pseudo random numbers An m of zero will cause RND to return the previous random number An m of greater than zero will cause RND to return the next random number in the sequence 10 R RND 1 20 S RND 0 30 T RND 1 40 PRINT R S T RUN 7 65943E 06 7 65943E 06 163989 none Commands 111 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR RUN Command RUN line To begin the execution ofa program RUN resets the numeric variables to zero string variables to null resets the interrupt pending flag and runs the current program RUN resets memory reserved by the last CLEAR statement RUN causes parts of the program to be compiled A typical program compiles at 800 lines per second RUN may also be used at run time with the optional line number The effect will be to clear all variables and reserved space Great care should be taken when using RUN with the optional line number NOTE The program must be compiled by executing RUN before performing a RUN line LOAD RUN 10 PRINT 7 1 20 PRINT HELLO RUN 20 HELLO lt Syntax gt if line not found when using RUN line Nonsense line number will be displayed Commands 112 SYNTAX PURPOSE REMARKS EXAMPLE ERROR SAVE Command SAVE SAVE program SAVE to Flash segment to Flash address from RAM segment from RAM address length Saves pro
112. ivate the task Another START INP will reactivate the task You do not need to execute ON INP to start the task again Declaring a Task This is done with the ON INP statement The syntax is ON INP n address mask com pare GOSUB line label Where n is the task number The range ofn is 0 to 7 address is the I O address of the port in interest The port can be an actual input port like that on an 82C55 a readable latch or an internal CPU register mask determines which of the input bits or lines are of interest For example if we want to look at lines 0 1 2 3 and 7 then the mask would be 10001111 in binary or 8F in hex or 143 in decimal The 1 bits of the mask are the bits of interest During execution the mask is ANDed with the port value If the result is equal to the compare parameter then a interrupt occurs The program then branches to the GOSUB line label The inputs are checked 200 100 in 9 MHz systems times per second In most applications the inputs will be changing much more slowly Thus if a match occurred and remained the same for one second then 200 100 in 9 MHz systems interrupts would occur To prevent this from happening the ON INP operates in the edge triggered mode The program branch occurs only on the first instance of the match All subsequent matches are ignored until at least one input changes so that a match is not present The example below will let you demonstrate the INP task
113. l a subroutine by name in addition to the line number This makes programs self documenting The example below shows a fragment of an over temperature program 10 IF TEMP gt 150 THEN 500 500 OUT HEAT O With labels the same code would be 10 IF TEMP gt 150 THEN HEAT OFF 500 HEAT OFF 510 OUT HEAT 0O The labels may be any length up to 40 characters Since they are pre compiled long labels do not slow program execution Line labels may be used only with GOTO and GOSUB statements They may not be used with ON GOTO or ON GOSUB type commands Labels may be used as a part of conditional IF THEN statements provided the GOTO command precede the labels 2 No line numbers Line labels m ean you can write code virtually w ithout line numbers The above examples could easily be written in a text file as IF TEMP gt 150THEN HEAT_OFF HEAT_ OFF Introduction 1 10 11 12 OUT HEAT 0 All you need is the addition of the AUTO command at the beginning of the program No program lines can be blank Each line must have a remark if nothing else Nonvolatile Variables CAM BASIC has a special set of 26 process variables A through Z that are not zeroed on power up or reset These variables are used in exactly the same manner as the normal variables With a battery backed RAM module these variables will automatically retain their values if the power goes off They also are pre compiled so they execute faster t
114. lt Out of string space gt when not enough string space is reserved Commands 16 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR CLEAR COM Process Statement CLEAR COM n To reset a serial port input buffer to the power up condition Executing this statement will clear the serial input buffer specified by n n legal serial port number The input buffer parameters are reset Any previous CONFIG COM and ON COM commands will be canceled This statement does not clear serial output buffers See the Multitasking Chapter for more information COM CONFIG COM ON COM The following clears the primary serial port input buffer 10 CLEAR COM 1 lt Datanegative gt forn lt Data out of range gt ifn is not a legal serial port number Commands 17 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR CLEAR COUNT Tasking Statement CLEAR COUNT n ni Gam To clear the accumulated count in a software event counter CLEAR COUNT is functional both during timed operation and when the counter is stopped The counter number n ranges from 0 to 7 See the Multitasking Chapter for more information NOTE This statement has no effect on 82C54 hardware counters CONFIG COUNT ON COUNT RESUME COUNT START COUNT STOP COUNT 10 CLEAR COUNT 0 10 CLEAR COUNT 5 6 3 lt Data negative gt forn lt Data out of range gt ifn gt 7 Commands 18 SYNTAX PURP
115. may be read at any time with the COUNT function This function is synchronized with the counter so that valid data is always read 35 You can program the counter so that the program branches to a subroutine when it reaches a preset am ount using the ON COUNT statement 4 You can also create a module n counter by having the counter automatically reset when it reaches a preset count using the CONFIG COUNT statement 5 The counters are 16 bit and can accumulate up to 65 535 counts 6 You can stop and zero the counters individually or in groups with the CLEAR COUNT statement 7 You can start the counting individually or in groups with the START COUNT statement 8 You can suspend counter operation while maintaining the count with the STOP COUNT statement 9 You can restart the counters without resetting the count using the RESUME COUNT statement How Counting is Done A specified input line is sampled 200 times 100 times in 9 MHz systems per second As shown in Figure 1 when the software detects that the input changes from a high logic state to a low logic state the counter is incremented Count input Sample Counter Increment Figure 1 Event Multitasking 3 Theoretically a 100 Hz square wave can be counted However due to sample timing variations dependent upon other multitasking events the maximum square wave frequency rate should be 80 Hz To obtain the full frequency response the minimum time the signal is l
116. mmand which is not implemented on your card For example the AIN is useless on cards without analog input Encountered an END DO without a previous DO n statem ent Self explanatory Error Messages 4 Event Multitasking Event Multitasking was developed to give faster response to real time events It is different than the multitasking that was originally designed for business applications and later used in some industrial control languages Time Slice Multitasking The Old Way This older form of multitasking usually takes two forms The most popular is called time slice Each task is written as if it were a separate program The first task starts and on a clock tick usually 60 times per second that task is suspended and the next task starts After another clock tick the second task is suspended and the third task begins This continues until all tasks have had their slice of time and the process starts over To get some idea of the performance level of this type of multitasking assume that there are 10 equal tasks Tasks are switched 60 times per second With 10 tasks each task is serviced only 60 10 or 6 times per second The second form is really a version of the first Tasks are switched after each command in each task This increases the task switching to several hundred times per second but the switching overhead seriously slows the throughput The problem with time slice is that all the tasks are written in BASIC Si
117. n gt available string space Commands 15 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR CLEAR Statement CLEAR string space To set all numeric variables to zero set all string variables to null restore the data pointer and negate all DIM statements You can optionally set the string space size If the optional parameter string space is specified variables are cleared and the string space is made equal to the number of bytes specified 100 bytes is the default value on power up You can figure the amount of string space by adding up the number of characters you expect each string variable to use and add the length of the longest string you will use Then add 10 to that total For example if you expect A to hold 75 characters and B to hold 45 you would need 45 75 75 x 1 1 215 For safety you should round up to the next 100 NOTE Make sure you execute CLEAR before you execute any DIM statem ent Execute this statement if your program uses a large number of string variables for storage or manipulation You will geta lt Out of string space gt error if there is not enough space set aside none The following clears all variables and sets the string space to 100 bytes 10 CLEAR The following clears all variables and reserves 500 bytes of RAM for strings 10 CLEAR 500 lt Datanegative gt for string lt Out of memory gt if an attempt is made to clear more memory than is available
118. n opto isolator racks that are external to the card The channel parameter ranges from 0 to 23 0 3 on RPC 30 or 100 to 123 and corresponds to the position numbers on the opto module racks The value is the state of the output To turn an output on enter a 1 or ON To turn the output off enter a 0 or OFF The ON and OFF execute faster than 1 or 0 Inputs and outputs are active low when interfacing with opto isolator racks Thus writing a 1 to an opto output module will turn it off This confusion is eliminated with the OPTO statement It automatically inverts the logic so that a 1 represents on and a 0 represents off The OPT O statement is similar to the BIT statement in that individual I O bits or channels can be controlled It differs in that it is used specifically with opto isolator racks and it executes much faster OPTO function 10 OPTO 3 0ON 20 PRINT OPTO 103 RUN 1 In this example channel 3 was turned on Thus a 1 is returned lt Data negative gt channel and value lt Data out of range gt if channel gt 23 or value gt 1 or ON OFF Commands 92 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR OUT I O Statement OUT I O address data Sends a byte to an I O address The J O address is any on or off card address in the range of 0 to 65 535 data is between 0 and 255 NOTE I O addresses 128 through 141 are used internally by the CPU Writing to these addresse
119. nce there is only one microprocessor chip and task switching takes processor time away from program execution the system will actually run slower than with a non multitasking program Event Multitasking For Real Time Control Event Multitasking in CAMBASIC solves the speed problem by compiling all tasks into machine code which executes much faster than BASIC CAMBASIC executes about 3600 commands per second which is very fast by BASIC standards It also can execute 5000 tasks per second in the background while maintaining the foreground rate NOTE These numbers are half for 9 MHz systems There are some limitations to this method You can only use the tasks defined by the language These are Output Timing PULSE Input Counting COUNT Keypad KEYPA D Communications COM Hardware Interrupts ITR Change of state on inputs INP Periodic Interrupts TICK A series of special commands are used for the tasks You do not use CAM BASIC commands like POKE GOTO etc for the tasks Hardware vs Software Interrupts It is important to understand the difference between hardware and software interrupts when dealing with a high level language CAMBASIC can respond to hardware interrupts but only indirectly When a hardware interrupt occurs an internal flag is set within a few microseconds In the same manner any task that can cause an interrupt set an internal flag Event Multitasking 1 Between each program statement CAM BAS
120. ncrement When both values are omitted the default is 10 10 When Zine is specified but not increment the default increment is 10 line is the initial number used to start num bering lines increment is the value added to each subsequent line AUTO is terminate by typing lt Enter gt with no other data on the line When a line already exists an asterisk is displayed after the number none The following generates lines number 100 150 200 etc AUTO 100 50 none Commands 7 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR BCD Numeric Function n BCD nm To return four digits n packed BCD format from a number The four BCD digits are stored in the variable n Each BCD digit is 4 bits and the four BCD digits are stored in 16 bit form These are known as packed BCD numbers One common use is to convert a count to BCD to send to displays that have BCD inputs BIN A 456 PRINT BCD A 1110 At first the answer above appears to be wrong This is due to the fact that the 4 digit BCD number has been packed into 16 bits and the print command is treating it as a binary number The following converts a 4 digit number and outputs it to two ports 10 N BCD 6789 20 M N AND 255 30 OUT 1 M 40 N N 256 50 OUT 2 N lt Illegal argument gt ifm gt 9999 lt Data negative gt form Commands 8 SYNTAX PURPOSE REMARKS EXAMPLE ERROR BIN Numeri
121. ng down sealing head for 4 seconds return Event Multitasking 15 emergency Emergency stop pressed Turn off all outputs out 2 255 return headup Head has moved up Time to move product over pulse 3 2 16 5 0 return preheat Pre heater done Now turn on heat for 1 second pulse 2 2 8 1 0 return Head Pre heat Heat Start Switch Pusher The restof your program starting after preheat executes independently ofthe timed outputs Each output will time without further intervention by the program Thus the program can do other tasks like handle communications check safety limits and acquire process data such as temperatures pressures etc The above example shows the timing generated by the program An active state is shown high Pressing a start switch initiates operation The head is on for the full heat time A pre heater is on for 2 seconds Then the real heater is on for 1 second The head stays down for an additional second before the pusher shoves the product out The sequence repeats when the start switch is pressed If the program should terminate before a timer times out the bit will be leftin the active state When program execution stops all timers are canceled If the program is restarted with the CONT statement the timers will not restart Event Multitasking 16 DIFFERENCES CAMBASIC vs QBASIC 1 CAM BASIC is a multitasking language while the others are not This adds features
122. nted However all PRINT statements execute properly Because the line numbers are printed execution is slowed The slowdown is less noticeable at higher baud rates To turn the trace off execute TROFF Use TROFF to turn off the trace function These two statements are most useful when tracing portions rather than entire programs Below is a test program 10 AS Down 20 TRON 30 FOR X 0 TO 2 40 GOSUB 90 Program debugging 1 50 NEXT 60 TROFF 70 END 80 S 0 90 INC H 100 RETURN RUN 30 40 90 100 50 40 90 100 50 40 90 100 50 60 USING MON TO EXAMINE MEMORY When storing data into memory it is sometimes necessary to verify that a block is correct You can display 128 bytes ata time with the MON D command The syntax is MON D address segment where address is the starting address in hexadecimal The command will display 8 lines of 16 bytes The optional segment parameter can be used to view memory segments above segment 0 The segment is entered in hexadecimal The program will pause at the end of each display Pressing the space bar will cause another block to be displayed Pressing lt ENTER gt returns you to the Immediate Mode Pressing lt ESC gt during the listing will abort the display Program debugging 2 The following list of error messages are returned by CAMBASIC These indicate clearly what is wrong within the context of a program and should be of great use in program debugging
123. nted in successive print zones 10 FOR X 1 TO 5 20 PRINT X 30 NEXT RUN This does a carriage return 10 PR NOTE The use of PR instead of PRINT does not save memory space It eliminates the number of keystrokes lt Data out of range gt ifn is not a legal serial port number lt Datanegative gt forn Commands 97 SYNTAX PURPOSE REMARKS RELATED EXAMPLE PRINT USING Statement PRINT n USING format string expression To print strings or numbers using a specified format n valid portnumber Portnumbers are 1 and 2 for serial 9 for VF display 10 for LCD character and graphics display LCD and VF displays must be configured using the CONFIG DISPLAY command before use The format string is one or two strings that specify the print format The three possibilities are Used to specify the number of digits to be printed on each side of the decimal point Used to print numbers in scientific or engineering notation This format string must contain 4 carets and be used in conjunction with the format string Failure to do the latter will produce unpredictable results Used to specify the location of the decimal point in a field determined by the use of NOTE You cannot print a string expression in the same line containing a format declaration The string will be taken as numerical PRINT PRINT A 1 2345 PRINT USING A 1 23 PRINT USING A 1 23 The sign in
124. null The default value is 11 for numerical values and 253 for strings This means that the numerical array subscripts for 0 to 10 are allowed The number of subscripts is always one more than the dimension The maximum number of dimensions for an array is 255 NOTE When CLEAR is executed all dimensioned arrays are redimensioned to 11 0 10 NOTE String arrays are single dimension only Unlike scalar variables dimensioned array names use only the first and last letters A variable name PUMP n is seen as the same as PP n and returns the same number The following dimensions a single dimension numeric and string array 10 DIM A 25 A 30 The following dimensions a numeric array with three dimensions 20 DIM B 10 10 10 lt Out of memory gt if dimensioned space exceeds memory lt Data negative gt if value is negative lt Array already dimensioned gt if an attempt is made to redimension an array or dimension an array that has already been referenced in the execution path Commands 33 DISPLAY Process Statement SYNTAX DISPLAY data data DISPLA Y data data DISPLAY format data DISPLAY text DISPLAY variable DISPLAY row column data data DISPLAY row column text DISPLAY row column data data DISPLAY row column USING format data PURPOSE To write information to character and graphic displays REMARKS The basic syntaxes above can be
125. o COM1 quick version of above LIST 1 list the entire program to COM1 LIST 2 list the entire program to COM2 LIST list 16 lines at a time LIST list program with no line numbers For simplicity the next group of variations shown for COM 1 LIST 50 list only line 50 LIST 100 500 list from the line 100 to line 500 LIST 220 list from line 220 to the end of the program LIST 50 list from the beginning of the program to line 50 To combine the two groups of variations LIST 2 10 200 list through COM2 from line 10 to line 200 LIST lists 16 lines ata time Pressing the space bar will list the next 16 lines Pressing any other key will abort the listing The command is valid only on the COM 1 port You can use the optional line numbers to define a range none Commands 72 ERROR lt Line not found gt if line does not exist Commands 73 SYNTAX PURPOSE REMARKS EXAMPLE ERROR LOAD Command LOAD LOAD program LOAD program RUN LOAD to RAM segment RAM address from memory segment memory address length LOAD with no parameters reads a program from Flash and puts it into RAM LOAD program retrieves a program from 0 or 1 ina 128K Flash EPROM or 0 to 7 in a 512K Flash and puts it nto RAM LOAD with all the other parameters transfers data from Flash to RAM or RAM to RAM LOAD with no parameters is the only valid LOAD command on the RPC 150 and RPC 2300 LOAD n RUN is used within a program
126. o write and retrieve data stored in memory This is very useful in data logging and process data storage and retrieval The first syntax applies to the first 64K of memory segment 0 For addresses above segment 0 use the second syntax Not all cards support segmented memory FPEEK and FPOKE are the fastest way to write and retrieve data from memory DPEEK DPOKE PEEK PEEK POKE POKE 10 FPOKE amp A000 1 25 20 A FPEEK amp A000 10 D FPEEK 200 1 lt Data gt 65 535 gt address data and segment lt Data negative gt for address lt Data out of range gt ifsegment gt 15 Commands 51 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR FRE Function a FRE 0 a FRE c Returns the number of bytes of unused but allocated string space or the number of bytes left for program and variables Also performs garbage collection on string space The argument 0 returns the number of bytes which are currently unused and available for program and variables When the argument is any string variable variable name does not matter the number of bytes of unused string space is returned It also clears up unused string space garbage collection Executing this function FR E c just before a section of code that manipulates a lot of strings can speed up program execution none On power up you type PRINT FRE 0 FRE AS 35210 100 The first number is the bytes for programs and all va
127. ome cases especially where time is critical it is desirable that the current program not be interrupted until it is completed When the command LOCK is executed any interrupts will be latched but not executed until the UNLOCK command is executed The UNLOCK RETURN is only used at the end of a GOSUB routine In this case a previous LOCK must occur in the subroutine For these commands to prevent any part of a subroutine from being interrupted LOCK must be the first line of the subroutine Therefore the GOSUB must use a line number not a label UNLOCK EXIT may be used to quickly get out of a FOR NEXT GOSUB or other nested routine 10 GOSUB 500 20 IF PRESSURE gt 234 THEN ALARM 1 500 LOCK 510 PRESSURE AIN 6 AIN 0 520 UNLOCK RETURN If this construct were not used an interrupt could occur between lines 500 and 510 and or between lines 510 and 520 and delay the alarm flag being set in line 20 none Commands 75 SYNTAX PURPOSE REMARKS EXAMPLE ERROR n LOG m To return the natural logarithm of m The natural logarithm is the logarithm to the base e 2 718282 PRINT LOG 45 7 1 86075 lt Illegal argument gt ifm is zero or negative Commands 76 LOG Numeric Function SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR MID String Function n MID m p q To return the requested part of a given string The function returns a string of length q c
128. on of m Performs conditional operations Increments variable by 1 Increments variable by 4 Returns serial characters Returns a byte from an I O port Returns data from serial port Returns string from keypad Returns the position of b in a Returns integer portion of b Returns last key from keypad port Returns left most characters of m Returns number of characters in m Command Summary 3 Command LINE LIST LOAD LOAD RUN LOCK LOG MID MOD MON NEW N BIT N COM N COUNT N ERR oO 80 80 Oo 8 N INP ON ITR ON KEYPAD ON TICK OPTO OR OUT PEEK PEEK POKE POKE PRINT PRINT USING Syntax a LINE n LINE n m LIST LOAD LOAD n RUN LOCK n LOG m n MID m p q MID m8 p 4 n n a MOD b MON NEW n NOT a Command OFF N expression GOSUB N BIT task addr bit GOSUB N COM chan GOS UB line N COUNT n GOSUB line N ERR GOTO line Or OTO Or OYO N INP n address mask GOSUB line label N ITR GOSUB line O ON KEY PAD GOSUB line ON TICK n t GOSUB line n OPTO channel OPTO n m n aORb OUT I O address data n PEEK address segment X PEEK address segment POKE address data segment POKES address a segment PRINT expression PRINT USING format exp Purpose Read a single line on a STB 26 Write to a line number on a STB 26 Outputs program listing Moves program from memory to RAM Loads program from Flash to RAM
129. or recovery procedure has been per formed If NEXT is not declared the main program will resume operation by re executing the statement that originally caused the error Every error handling routine must eventually end either by executing a RESUME statement or by terminating the program If NEXT is specified execution resumes at the statement immediately following the one which caused the error When an error trap occurs it has the effect of disabling the ON ERR GOTO statement that enabled the trap Any further error occurring prior to the execution of another ON ERR GOTO statement will cause the termination of the program An ON ERR GOTO statement may be included at the end of the error handling routine to maintain the error trap enabled Error traps may be nested in the same manner as GOSUBs and function calls and the error routine may begin with an ON ERR GOTO statement with its own error handling routine Each error handling routine must be terminated with a RESUME statement NOTE You cannot use program labels with RESUME Make sure you re declare error handling using ON ERR When the error routine is executed the previous ON ERR is disabled Consider using EXIT CLEAR in an error handling routine This will clear loop stacks and subroutines You can then start at the beginning of your program ON ERR lt RESUME w o ON ERR gt if no corresponding error condition lt Can t compile gt if line does not exis
130. ounter reaches 65 535 the next count will roll the counter over to zero This mode requires only that CONFIG COUNT and START COUNT be executed in that order A short example would be 10 CONFIG COUNT 5 0 1 2000 AUTO 20 START COUNT 5 Line 10 configures counter 5 to read bit 1 of address 0 as an input When the count reaches 2000 the counter will automatically reset Line 20 starts counter operation These two lines do not need to be adjacent in the program However line 20 must be executed after line 10 Event Multitasking 4 The second is the interrupt mode When the preset count is reached a software interrupt is generated and the program branches to a subroutine which acts on the preset count This mode requires that CONFIG COUNT ON COUNT and START COUNT be executed in that order Below isa short example of a prescaler 10 CONFIG COUNT 5 0 1 2000 AUTO 20 ON COUNT 5 GOSUB 200 30 START COUNT 5 200 INC A 210 RETURN Line 10 configures counter 5 to read bit 1 of address 0 as an input When the count reaches 2000 the counter will automatically reset Line 20 directs CAM BASIC to branch to a subroutine when the preset count is reached Line 30 starts counter operation These three lines do not need to be adjacent in the program However they must be executed in this order Line 200 increments variable A Thus the value of A is the number of times the counter has counted to 2000 Line 210 returns program execution to the plac
131. ow or highis 8 mS The software is written to reject high frequency noise Defining a Counter Setting up a counter is done with the CONFIG COUNT statement The syntax is CONFIG COUNT counter address bit preset AUTO Where counter is the counter number which may be 0 through 7 address is the I O address of the port of 8 bits that you want to use for the input This will typically be an 82C55 port bit is the particular bit or line of the port addressed The range is 0 through 7 preset is an optional parameter that tells the counter to notify the system when a preset count has been reached The program will branch if an ON COUNT statement has been executed The value may range from 1 to 65 656 AUTO is an optional parameter Without AUTO the counter will continue to increment after the preset count is reached When AUTO is specified the counter will reset to zero after reacting the preset count This way no counts are missed while the subroutine branch is executing Background Tasking is Much Faster The data that you enter with the CONFIG COUNT and ON COUNT statements is compiled into object code Thus the execution time on the 200 Hz 100 times in 9 MHz systems clock tick is only microseconds rather than the milliseconds that it would take in BASIC Modes of Oper ation At there are two modes of operation The first is the polled mode in which counts are accumulated and read from time to time by the program When the c
132. p 40 with no visible cursor Commands 36 Lines 20 to 50 define the four strings to be printed Lines 60 to 90 display the strings in the random access mode Line 100 has a 2 second delay Lines 110 and 120 erase all four lines two at a time by writing a strings of 80 spaces to each line Line 130 is a 0 5 second delay and the program repeats ERROR lt Data negative gt for row and column lt Data out of range gt if row or column exceed that for the specified display Commands 37 SYNTAX PURPOSE REMARKS EXAMPLE ERROR DO ENDDO Statements DO value ENDDO To execute a loop a number of times quickly value range is 1 to 65535 It can be a number or variable The DO ENDDO statements cause a list of statements to be executed for a number of times It is 3 times faster than using a FOR N EXT loop You can NOT exita DO ENDDO with the EXIT statement A way to gracefully exit a DO ENDDO loop isto set DO 1 then GOTO the line at ENDDO NOTE Nesting of DO ENDDO loops is NOT permitted This construct s speed is due to the use of a single counter 10 A 45 20 DO 45 30 INC A PRINT A 50 ENDDO Nesting DO ENDDO loops is NOT allowed An example of what NOT to do is shown below DO 25 GOSUB routine ENDDO routine DO 50 A AIN 0 A ENDDO RETURN A DO loop counter empty error is returned after the GOSUB routine lt ENDDO gt if ENDDO encountered without corresponding DO
133. ports are configured they can simultaneously capture data in the background while the program executes If the ON COM statement is used CAMBASIC will branch to the user s routine to handle the incoming data when the message is complete Both ports also have output buffering When the PRINT statement is executed the characters to be printed are sent to the multitasker and program execution continues at the next statement The program does not wait until all the characters are printed This is especially useful when data is being transmitted at a low baud rate over a modem or radio link The output buffers are 255 characters long Real time Multitasking CAMBASIC can perform several kinds of tasks at assembly language speed while the program is running See the Multitasking Chapter for more information Concepts 2 Reserved Words CAM BASIC comprises a set of statements commands and function names which are treated as reserved words and cannot be used at the beginning of variable names These are sometimes referred to as keywords Character Set The CAMBASIC character set includes all characters which are legal in CAMBASIC commands statements functions and variables The set comprises alphabetic numeric and special characters Alphabetic characters are automatically converted to upper case unless they are part of a string and enclosed in quotation marks or are part of a remark Numeric digits are 0 through 9 Any character whether pr
134. r a number of industrial commands Each sub command has a list of parameters See the CONFIG Chapter for details The configuration variations are CONFIG BAUD sets the serial port parameters CONFIG BREAK enables disables break characters CONFIG CLOCK set up calendar clock CONFIG COM defines the serial port interrupt CONFIG COUNT sets the event counter parameters CONFIG DISPLAY defines display type CONFIG PIO initializes parallel I O ICs See CONFIG Chapter for more information See CONFIG Chapter See CONFIG Chapter Commands 23 SYNTAX PURPOSE REMARKS EXAMPLE ERROR CONT Command CONT To resume program execution after a break The CONT command may be used to resume program execution after a break from the serial port or an END or STOP statement has been executed Execution continues at the point where the break happened CONT is invalid if the program has been edited during the break or if any statements have been executed in the immediate mode WARNING All tasks and sound output are canceled when a program stops CONT inuing when using multitasking is not recommended In the following example we create a long loop 10 A 1 20 PRINT A 30 INC A GOTO 20 RUN 1234567 8 At this point we interrupt the loop by pressing ESC lt Stop gt lt Ln 20 gt CONT 9 10 11 12 13 14 15 16 17 18 19 20 CON T if executed after a program edit Commands 24 SYNTAX PURPOSE
135. riables The second is the default string The line below increases the string space to 1000 bytes CLEAR 1000 PRINT FRE 0 FRE A 34310 1000 Notice that the unused string space is now 1000 which reduced the total program and variable space by 900 bytes none Commands 52 SYNTAX PURPOSE REMARKS EXAMPLE GOSUB Statement GOS UB line label RETURN To branch to and return from a subroutine line label is the beginning of the subroutine A subroutine may be called any number of times in a program and a subroutine may be called from within another subroutine The RETURN statement causes CAM BASIC to branch back to the statement following the most recent GOSUB statement A subroutine may contain more than one RET URN statement should logic dictate a return at different points in the subroutine Subroutines may appear anywhere in the program To prevent inadvertent entry into the subroutine you may put an END or GOTO statement in front of it to direct program control around the subroutine NOTE The execution of the GOSUB statement is independent of the location of the target line in the program No run time search occurs When a label is used with GOSUB a statement cannot follow GOSUB on the same line 10 GOSUB 40 20 PRINT Back from subroutine 30 END 40 PRINT subroutine 50 PRINT in 60 PRINT progress 70 RETURN RUN subroutine in progress Back from subroutine Commands 53
136. s does a short delay and prints again Line 50 increments a variable and represents the number of seconds In some applications multiple interrupts are required This can be done with the TICK statement The only limitation is that the interrupt times must be multiples of each other For example 1 0 and 3 0 seconds would be acceptable but 1 0 and 2 7 seconds would not Below is a program that demonstrates clock interrupts every 1 and 5 seconds 10 ON TICK 0 1 GOSUB 50 20 PRINT foreground 30 DELAY 25 40 GOTO 20 50 PRINT TAB 20 tick 60 INC A IF A 5 THEN A 0 GOSUB 70 ELSE PRINT RETURN 70 PRINT tock 80 RETURN Line 10 sets up an interrupt every 1 00 seconds Lines 20 through 40 simulate your foreground program as in the first example Line 50 prints tick every second Line 60 increments a second counter When it reaches 5 the counter is reset and tock is printed at line 70 Event Multitasking 13 PULSE MULTITASKING Introduction CAM BASIC supports eight timed or pulsed outputs These are generated in software and have a resolution of 5 milli seconds Each timer is assigned through software to any digital I O line on any CPU or expansion card Once configured timing is done independently in the background The timers have the following features 1 The time resolution is 5 mS 10 mS in 9 MHz systems 2 The timers may be read at any time with the PULSE function 3 The timers are 16 bit with a rang
137. s may disrupt system functions BIT INP In the following example the number 2 is written to I O address 100 OUT 100 2 lt Datanegative gt for address data lt Data gt 255 gt for data lt Data gt 65 535 gt for address Commands 93 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR PEEK and POKE Memory Function and Statement n PEEK address n PEEK address segment POKE address data POKE address data segment PEEK returns a byte from memory POKE writes a byte to memory The returned value from PEEK will be an integer in the range 0 to 255 address is the address in memory PEEK is the complement to the POKE statement The first syntax applies to the first 64K of memory segment 0 For addresses above segment 0 use the second syntax Not all products support segmented memory DPEEK DPOKE PEEK POKE FPEEK FPOKE 10 A PEEK amp 7000 10 A PEEK amp 2000 1 20 POKE amp A000 12 1 lt Datanegative gt for address data and segment lt Data gt 65 535 gt for address lt Data out of range gt if segment gt 15 Commands 94 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR PEEKS and POKES Memory Function and Statement x PEEK address x PEEK address segment POKE address X POKE address X segment PEEKS returns a string from successive memory addresses POKE writes a string to memory The first
138. s deleted and the word was was inserted 10 PRINT This was PRINT a simple edit Program Editing 3 Replace The Replace command does a delete and insert on a character basis For example EDIT 10 10 PRINT 10 _ Now press the lt SPC gt until the cursor is under the a 10 10 Type lt R gt 10 10 10 PRINT PRINT and then lt I gt PRINT PRINT PRINT This is PRINT a sample edit 66 in sample This is PRINT This is PRINT a sample edit as_ 66 You have replaced the a This is PRINT This is PRINT This is PRINT a sample edit a si a simple edit with an I Finally type lt ENTER gt If you change your mind in the middle ofa Replace you can exit by pressing lt ESC gt Extend The Line To add more to the end of an existing line type lt X gt character past the end of the line and enters the Insert Mode This command moves the cursor to the next The cursor will change from the underline to the block You may now insert test Program Editing 4 How to Maximize Execution Speed 1 Use the pre compiled variable A to Z In an average program these will run 50 faster Use as many as possible especially in FOR NEXT loops and software counters For other variables there is a lookup time To minimize lookup time declare the variables at the beginning of the program to force them to be at the beginning of the vari
139. s example the bit 0 of the port at address 0 was set high lt Data negative gt terminal Commands 70 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR LINE Process Statement LINE terminal value To write directly to the STB 26 terminal board The terminal has a one to one correspondence with the terminals on the STB 26 This feature eases documentation and troubleshooting Refer to card manual for terminal number range The LINE statement is similar to the BIT statement in that individual I O bits or channels can be controlled It differs in that it is used specifically with the STB 26 terminal board and it executes much faster The value is the state of the output To turn an output on enter a 1 or ON To turn the output off enter a 0 or OFF The ON and OFF execute faster than 1 or 0 LINE function 10 LINE 113 0N 20 PRINT LINE 113 RUN In this example line 3 was turned on Thus a 1 is returned lt Data negative gt terminal 1 and value lt Data out of range gt if value gt 1 or not ON OFF Commands 71 SYNTAX PURPOSE REMARKS RELATED LIST Command LIST line line LIST line line LIST To list a part or all of the program currently in memory You can stop the listing by pressing lt ESC gt The program is listed through the COM1 serial port unless you specify otherwise The basic variations are LIST list the entire program t
140. s not work in hidden programs lt Line label not found gt If the first line does not exist Commands 31 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR DELAY Statement DELAY n To create a precision delay The resolution is 5 mS 10 mS on 9 MHz systems Program execution is suspended during the delay period Interrupt service will be delayed until the end of the delay period For breakable delays use a FOR N EXT loop For applications which require high accuracy the execution of the DELAY statement itself and the number of interrupts occurring must be considered If a delay of 0 is specified the delay will be less than 0 5 mS NOTE This command uses a 5 mS system clock 10 mS in 9 MHz systems The actual delay can vary by 0 005 0 010 seconds Background tasks are latched but not serviced during the delay period Pressing lt ESC gt will abort the delay and stop the program None 10 DELAY 5 delays second 10 DELAY 3 25 delays 3 25 seconds lt Datanegative gt forn lt Time gt 327 67 gt forn Commands 32 SYNTAX PURPOSE REMARKS EXAMPLE ERROR DIM Statement DIM variable value variable value To specify the maximum size for array variables and reserve memory accordingly The DIM statement sets all elements of the specified numerical arrays to an initial value of zero String array elements are of variable length with an initial value of zero
141. s odd parity If the mode parameter is set for no parity then enter a 0 com is an optional parameter and is valid only for COM2 on boards with a RS 422 485 port It determines if this port is RS 232 RS 422 or RS 485 When in RS 485 mode the output is automatically turn on when printing and turn off when it is finished The transmitter is turned off CONFIG Commands 2 within one character time after the last character is sent 0 RS 232 de fault 1 RS 422 transmitter always on 2 RS 485 RPC 2350 NOTE The CAM BASIC statement BIT 128 4 0 may need to be executed before you will receive any characters This command enables the CTS line to the sender RELATED none EXAMPLE 10 CONFIG BAUD 1 7 5 0 This sets COM1 for the default values ERROR lt Data negative gt all parameters lt Data out of range gt if illegal baud mode or parity parameter CONFIG Commands 3 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR CONFIG BREAK Statement CONFIG BREAK com port mode To enable or disable response to a break character on a communications port In normal operation an lt ESC gt to COM1 while the program is running will stop program execution The same is true for C in an INPUT statement This response is disabled with CONFIG BREAK The com port parameter is 1 or 2 The mode parameter tells the system whether or not to suppress break A 0 will allow normal break operation
142. se include D A s A D s UART s and other devices The number of ports is hardware dependent The SPI function is used to read and write data Unfortunately SPI has a variety of data formats Data to send and receive from a device can be anywhere from 8 to 24 bits The clock polarity can idle high or low and the phase when data is latched The SPI function supports the following format Clock idle polarity low Clock data phase low This format supports the Maxim MAX186 188 and Burr Brown AD S7843 IC s If your format needs are different the CAMBASIC program SPIDEM O BAS can be used as a basis to read and write to other SPI devices Some boards such as the RPC 2350 have pre assigned ports Refer to your hardware manual for specific information Not all boards support this command such as the RPC 150 and R PC 2300 none 10 SPI 2 8 amp e8 10 12 lt Dataneg gt for any parameters Commands 118 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR n SQR m Calculates the square root of a number m is any positive number raise to power of mathematical function PRINT SQR 1 5 1 22474 lt Illegal argument gt when m is negative Commands 119 SQR Numeric Function SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR START BIT Tasking Statement START BIT task number task number To enable a BIT task that has previously been defined with
143. set up so that the first character is the upper left hand corner and the last character is the lower right hand corner You can assign a single character string to the keys in the following manner 10 FOR X 0 TO 15 20 READ AS 30 POKE SYS 8 X ASC A 40 NEXT 50 DATA 1 2 3 A 4 5 6 B 7 8 9 C 0 D This example matches the KP 1 Keypad except that the sign is replaced by a carriage return value 13 Applications Examples Basic 16 Key Example The first example is written for the KP 1 Keypad No characters were entered into RAM The CAMBASIC system defaults to the KP 1 character set 10 Basic 16 Key Demo Program 40 ON KEYPAD GOSUB Key interrupt 50 GOTO 50 60 Key interrupt 70 PRINT KEYPAD 0 80 RETURN Line 40 tells CAM BASIC to call a subroutine by the name of Keypad_interrupt every time a key is pressed Line 50 is used only as part of this demo program so that the system will wait You could insert the rest of your control program Line 70 prints the keypad character Event Multitasking 9 Line 80 returns program execution to the place that it was executing before the key was pressed Inputting Multi digit Numbers The basic examples print out the key that was pressed The following example is a variation of the basic 16 key demo that inputs a multi digit number 10 Input a multi digit number 30 ON KEYPAD GOSUB Key interrupt 35 PRINT R 40 DELAY 25 45 GOTO 35 50
144. syntax applies to the first 64K of memory segment 0 For addresses above segment 0 use the second syntax Not all products support segmented memory NOTE Due to compiler memory allocation executing PEEK in the immediate mode will return an error 30 lt Expected gt error DPEEK DPOKE PEEK FPEEK POKE FPOKE 10 A String 20 BS stuffer 30 POKES 0 AS 1 40 POKES 10 BS 1 50 PRINT PEEKS 0 1 PEEKS 10 1 RUN string stuffer lt Datanegative gt for address data and segment lt Data gt 65 535 gt for address lt String too long gt if string gt 254 characters lt Data range gt if segment gt 15 Commands 95 PURPOSE REMARKS RELATED EXAMPLE PRINT Statement PR n expression or expression PRINT n expression or expression To output data through the specified serial or display port If all of the expressions are omitted a carriage return is performed If the list of expressions is included the values of the expressions are displayed on the screen The expressions in the list may be numeric and or string expressions String constants must be enclosed in quotation marks The position of each printed item is determined by the punctuation used to separate the items in the list In the list of expressions a comma causes a tab to the next print zone print zones are 14 characters wide A semicolon does not place any spaces between the
145. t TIME statement and DATES 10 20 30 11 23 TIMES 11 23 45 PRINT TIMES 0 PRINT TIMES 1 2 23 45 245 lt Datanegative gt forn lt Illegal argument gt ifn gt 1 Commands 133 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR TIME Statement TIME time string TIME is used to set the time on the system calendar clock The clock keeps time on a 24 hour basis with a resolution of one second The time string may be a variable or a constant In either case the format is the same The string must be in the form hh mm ss where Ah is the hour and ranges from 00 to 23 mm is the minute 00 to 59 and ss the second 00 to 59 NOTE No error checking is done on the entries If you enter 99 for the minutes no error message will be given TIME function and DATE 10 TIMES 11 23 45 10 A 01 45 12 20 TIMES A lt Syntax gt if two digits are not used hh mm ss or if digits not 0 9 are entered Commands 134 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR TRON TROFF TRON TROFF Statement To trace program execution Execute TRON to turn on the trace and TROFF to turn the trace off It may be executed in the immediate mode to trace a whole program or be placed within a program to trace only a section WARNING TRON and TROFF must be the only command or last command on a line TRON should be used cautiousl
146. t Commands 107 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR RESUME COUNT Tasking Statement RESUME COUNT m m1 m2 mn To reenable a software event counter The statement reenables a counter after a STOP COUNT statement has been executed The counter contents remain unchanged The m parameter is the count number which ranges from 0 to 7 See the Multitasking Chapter for more information CLEAR COUNT CONFIG COUNT ON COUNT START COUNT STOP COUNT 10 START COUNT 2 20 STOP COUNT 2 30 RESUME COUNT 2 lt Data negative gt form lt Data out of range gt ifm gt 7 Commands 108 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR RETURN Statement RETURN line label RETURN ITR number To resume execution after a GOSUB interrupt multitasking or communications call The RETURN ITR reenables the interrupt RETURN is used as a return from a GOSUB call Program execution continues at the statement following the GO SUB number is 0 or 1 or as limited by your hardware It is the interrupt number that the subroutine declared by ON ITR n declared If the optional line label is specified the program will branch to the specified line label RETURN ITR is used as a return from an ON ITR GOSUB declaration In this case the return is to the next statement where the interrupt occurred The hardware interrupt is reenabled If ITR number is left off the return is s
147. t gt if counter gt 7 lt Data negative gt for counter Commands 26 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR DATA Statement DATA constant constant To provide a means to store numeric and string constants and object code programs The data may be accessed by the READ statement DATA statements are skipped over during execution and may be placed anywhere in the program A DATA statement may contain as many constants as will fiton a line and any number of DATA statements may be used in a program The information contained in the DATA statements may be thought of as one continuous list of items regardless of how many items are on a line or where the lines are placed in the program The READ statements access DATA statements in line number order Each constant may be a numeric or string constant No expressions are allowed in the list The numeric constants may be decimal or hex String constants in DATA statements need to be surrounded by quotation marks You can use the RESTORE statement to reread information from the beginning of the list of DATA statements See the RESTORE statement READ RESTORE See the READ statement none Commands 27 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR DATE System Statement DATE date string DATES is used to set the date on the system calendar clock The system clock keeps time on a 24 hour basis with a resolution o
148. t memory addresses This program works by reading the last byte written to this port performing the bit operation and writing it back to the same I O address Ports like those on the 82C55 can be read back The BIT statement cannot be used with ports that lack read back capability Four syntaxes are allowed The first syntax is the most flexible as the value parameter can be a variable The next three are more descriptive where ON sets the bit high OFF sets the bit low and NOT writes the complement ofthe bit These execute faster than the first variation and are self documenting BIT function INP ON BIT OUT 10 BIT amp 10 2 1 Set bit 2 of address amp 10 to a high state 10 BIT amp 10 5 A Set bit 5 of address amp 10 to the value of A 10 BIT amp 10 1 0OFF Set bit 1 of address amp 10 to a low state 10 BIT amp 10 0 NOT This reverses the value of bit 0 at address amp 10 lt Data negative gt if I O address bit or value lt Data out of range gt if value is not 0 1 ON NOT or OFF or if bit gt 8 lt Data gt 65 535 gt for O address Commands 12 SYNTAX PURPOSE REMARKS CALL Statement CALL address m1 m2 To execute an assembly language program at the specified address and optionally to pass data The specified address may be an expression and is the absolute address of the assembly language program The optional data may be expressions After conversion to 16 bit integers
149. t of the keypad string table Keys may be redefined by PO KEing into the address corresponding to the key s new value The following routine prints the address of the keypad string and the key values 10 FOR N SYS 8 TO SYS 8 15 20 A PEEK N 30 PRINT N A CHRS A 40 NEXT SYS Q and SYS 10 return the number of characters in the COM1 port input buffer and the COM2 port input buffer SYS 11 and SYS 12 return the COM1 port buffer full flag and the COM2 port buffer full flag 0 means the buffer is not full 1 means the buffer is full SYS 13 and SYS 14 display the cursor position of the VF display lt Datanegative gt forn lt Illegal argument gt ifn gt number of functions Commands 129 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR PRINT TA B m To tab to position m m ranges from 0 to 255 If the current print position is at or beyond space m TAB is ignored PRINT PRINT S TAB 10 E S E lt Data negative gt form lt Data gt 255 gt form Commands 130 TAB Print Function SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR n TAN m To return the trigonometric tangent of m TAN Numeric Function The angle m must be in radians To convert degrees to radians multiply by PI 180 where PI 3 141593 ATN COS SIN 10 PRINT TAN 1 5 14 1014 none Commands 131 SYNTAX PURPOSE REMARKS
150. ta 00 FF An optional segment may be entered MATH This feature is a hexadecimal calculator You enter two 8 bit numbers and the Mini Monitor displays the sum difference and product of the two MON gt M 65 44 AQ 21 1AD4 QUIT This command is used to exit the Mini Monitor and return to CAMBASIC Mini Monitor 2
151. tended memory This function returns an integer value that is the address in memory at which the value of a specified numeric variable or numeric array resides VARPTR will not return the address of a string array This function may be used directly in the PEEK or POKE functions and in the CALL statement for memory address references The format of the stored CAMBASIC variable values is as follows Numbers are first normalized to a standard fractional binary form with the binary point to the right of the sign bit of the mantissa and stored in four bytes The least significant byte appears at the lowest address The first three bytes are the mantissa with the sign in the most significant bit of the third byte A sign bit of 1 designates a negative value The fourth byte contains the exponent in excess 128 notation i e the value is always positive and equals the actual binary exponent plus 128 As an example the hexadecimal string LSB Man tissa MSB Exponent MMMMMMMM MMMMMMMM S MMMMMMM 1EEEEEEE Mem Mem 1 Mem 2 Mem 3 The normalized binary notation yields decimal equivalents which may not be obvious The floating point numbers are shown with the LSB on the left For more information see An Introduction to Microcomputers Volume 1 by Osborne McGraw Hill Scalar simple and numeric array variables reside above a program in RAM and are relocated upward as new program lines are entered Strings are stored one charac
152. ter per byte with the left hand character first The address returned is the left hand character Commands 137 EXAMPLE 1 EXAM PLE 2 EXAMPLE 3 EXAMPLE 4 Strings are stored in two ways A literal string e g A string is stored in the program line in which it appears Other strings that are formed as a result of string operations like concatenation are stored starting at the top of RAM and build down towards the numeric variables On power up you have 100 bytes of string space You can change this with the CLEAR statement Beneath the string area is the stack Thus unused RAM extends from the top of the array space to the bottom of the stack 10 A 1 1 20 B VARPTR A 30 PRINT B 40 FOR X 0 TO 3 50 PRINT PEEK B X 60 NEXT PRINT RUN 17487 205 204 12 129 This example is for a simple numeric variable The first number printed is the address of the first byte of the floating pomt representation of the number or 1 1 This is the same as shown on the previous page 10 H O 1 1 20 Z VARPTR H 0 30 PRINT Z 40 PRINT PEEK Z PEEK Z 1 PEEK Z 2 PEEK Z 3 RUN 17512 205 204 12 129 This routine returns the address of the first element of array H The next element if present would be at address 17004 the next at 17008 and so forth Addresses of array variables change each time a simple variable is assigned For example 10 T 0 0 20 PRINT VARPTR T 0 30 W
153. ters The first two syntaxes are for the RPC 2300 and RPC 150 Only a 16 position keypad is supported on these cards The last two syntax are for the RPC 2350 and RPC 2350G size specifies the keypad size of 16 or 24 KEYPADS SYS 8 10 ON KEYPADS GOSUB 70 20 30 GOTO 20 70 PRINT KEYPADS 0 80 RETURN lt Can t compile gt if line label does not exist Commands 89 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR ON TICK Tasking Statement ON TICK n t GOSUB line label ON TICK n t GOSUB To cause periodic program branching This statement is used when periodic tasks must be executed The GOSUB is executed every t seconds n is the tick number and ranges from 0 to 2 Up to 3 ON TICK subroutines can execute simultaneously There are three TICK timers in CAMBASIC The parameter n ranges from 0 2 The TICK timers are independent of each other The range of ft is 0 005 to 327 68 seconds The GOSUB branch occurs every seconds unless the second syntax 1s executed Not specifying a line number or label after GOSUB disables the ON tick subroutine Every seconds an interval flag is set At the conclusion of the current CAMBASIC command a GOSUB branch occurs See Multitasking Chapter for more information CLEAR TICK TICK 10 ON TICK 1 1 GOSUB 50 20 PRINT 30 FOR X 0 TO 600 NEXT 40 GOTO 20 50 PRINT TICK 1 60 RETURN lt Datanegative gt fortandn lt Data out of range
154. the RENUM command Concepts 1 Line Labels You can write a program to GOTO or GOSUB to a label instead of a line number This makes for more readable code 90 A3 AIN 0 100 GOSUB FILTER 110 IF FL gt 138 THEN GOTO OVER_LIMIT 5460 FILTER 5470 FL 875 FL 125 A3 5480 RETURN 8950 OVER_LIMIT 8960 OUT 49 3 shut down Using line labels makes it easier to review code You would probably know what FILTER does before remembering the line number it is on Line labels must be the first and only information on a line NOTE Labels may not be used with ON GOTO ON GOSUB RESTORE or RESUME When labels are used with GOTO etc no other statements may follow the label on the same line Debugging CAMBASIC provides you with several methods to help debug your program As with all debugging technique is usually more important than tools See the Debugging Programs Chapter for more information Bit Manipulation CAMBASIC has commands for manipulating and reading bits The BIT statement and BIT function can modify and read individual bits In order to modify a bit at an I O port the port must first be read the appropriate bit set and the byte written back to the port The BIT statement does this automatically The BIT function reads back individual bits It returns a 1 or 0 to reflects the state of the bit Communications Ports CAMBASIC supports two serial ports COM 1 console and COM2 Once the serial
155. till to the next statement where the interrupt occurred However interrupt number is disabled until a RETURN ITR number is executed or ON ITR GOSUB is declared again This is useful when you want to recognize an interrupt once and enable it again at some later time GOSUB ON ITR 10 ON ITR 0 GOSUB 40 20 A 23 This is a dummy loop 30 GOTO 20 40 PRINT Interrupt 50 RETURN ITR 0 lt RETURN w o GOSUB gt ifno corresponding GOSUB lt Can t compile gt if line label does not exist lt Data out of range gt if number is not 0 or 1 when used with ITR lt Expected gt if number is missing when used with an ITR Commands 109 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR n RIGHT m8 p To return the right most p characters of m as a string RIGHTS String Function If p is greater than or equal to LEN m then m is returned If p is zero a null string is returned LEFT MID LEN INSTR 10 AS ABCDEFG 20 PRINT RIGHTS A 3 RUN EFG lt Datanegative gt forp lt Data gt 255 gt forp Commands 110 SYNTAX PURPOSE REMARKS EXAMPLE ERROR RND Numeric Function n RND m To return a pseudo random number between 0 and 1 The RND function returns a pseudo random number between 0 and 1 An m of less than zero will initialize the pseudo random number sequence Each time the pseudo random number generator is initialized w
156. to lt less than Xx lt Y or equal to Relational operations return a value of 0 if false 1 if true Logical Operators Logical operators perform logical or Boolean operations on numeric values Just as relational operators usually make decisions regarding program flow logical operators usually connect two or more relations and return a true or false value to be used in a decision see IF statement in CAMBASIC COM MANDS A logical operator takes a combination of true false values and returns a true or false result An operand of a logical operator is considered true if it is not equal to zero like the 1 returned by a relational operator or false if it is equal to zero The result of the logical operation is a number which is again true if it is not equal to zero or false if it is equal to zero The number is calculated by performing the operation bit by bit The logical operators are NOT AND XOR and OR In the following table T indicates a true or nonzero value F indicates a false or zero value The operators are listed in order of precedence A NOTA A B A ANDB T F T T T F T T F F F T F T F F F F F F A B A ORB A B A XOR B T T T T T F T F T T F T F T T F T T F F F F F F Logical operations are carried out on 16 bit operands with 16 bit results The examples use 8 bit operands for simplicity The OR operator essentially detects the presence o
157. und in other BASICs none Commands 66 SYNTAX PURPOSE REMARKS RELATED EXAMPLES ERROR KEYPAD Process Function a KEYPA DS 0 a KEYPA D 1 To return a one character string in response to a keypad input or return the position of the key KEYPA D 0 returns a single character string that has been assigned to a key It is most useful on 16 key devices If no key was pressed or if you read the keypad again before another key is pressed a null string is returned KEYP AD 1 returns the key position Keypads often have legends that are not single letters Thus the first syntax may not make sense If no key was pressed or if you read the keypad again before another key is pressed a zero is returned A table in RAM can be programmed to return any ASCII value The table is set up so that the first character is in the upper left hand corner and the last character is in the lower right hand corner See SYS 8 You can assign a single character string to the keys in the following manner 10 FOR X 0 TO 15 20 READ AS 30 POKE SYS 8 X ASC A 40 NEXT 50 DATA 1 2 3 A 4 5 6 B 7 8 9 C 0 D This example matches many 16 position keypads ON KEYPAD INPUT KEYPAD 40 ON KEYPAD GOSUB Key interrupt 50 GOTO 50 60 Key interrupt 70 PRINT KEYPADS 0 80 RETURN The RPC 2350 requres an extra parameter 16 or 24 after KEYPA D to designate keypad size none Commands 67 SYNTAX
158. used to write to the DP seriesand LCD series displays Before using the DISPLAY command you must first execute the CONFIG DISPLAY statement to install the driver for your display text is a literal or assigned string DISPLAY A or DISPLAY This is text variable is any number function or evaluation DISPLAY N or DISPLAY N 35 or DISPLAY TICK 0 There are two ways to access the display sequential and random access In the sequential mode characters are displayed starting from the last position continue to the right The random access mode lets you place the cursor anywhere on the display using row column parameters and commence wr iting at that point On power up the cursor position is atrow 0 and column 0 Printing will continue to the right At the end of the line the DP series displays wrap to the next line The LCD displays generally do not wrap The cursor must be positioned to the next line Commands 34 Random access mode is most commonly used when presenting data or during operator feedback You specify a row and column where you want the first character to be printed The third syntax formats the data like the PRINT USING command in other BASICs LCD character display notes The integrated electronics within the LCD displays treat the unit as either one or two 1x80 displays If the lines are 40 characters long then there are two physical lines rows The first hasa column range from 0 to 39 and the secon
159. values from a DATA statement and assign them to variables See the DATA state ment A READ statement must always be used in conjunction with a DATA statement READ statements assign DATA statement values to variables in the READ statement on a one to one basis READ statement variables may be numeric or string A single READ statement may access one or more data statements they will be accessed in order or several READ statements may access the same DATA statement If the number of variables is fewer than the number of elements in the DATA statement s subsequent READ statements will begin reading data at the first unread element If there are no subsequent READ statements the extra data is ignored To reread the DATA statements from the start use the RESTORE statement CLEAR also restores the data pointer DATA RESTORE 10 FOR X 1 TO 9 20 READ A X 30 NEXT 40 DATA 153 124 5432 10 7 812 11 50 DATA 201 332 762 902 0 34 69875 This program segment READs the values from the DATA statements into array A After execution the value of A 1 will be 153 and so on lt Syntax gt if data type does not match variable type lt Out of DATA gt if the number of RE ADs exceed the number of data Commands 103 SYNTAX PURPOSE REMARKS EXAMPLE ERROR REMARK Statement any characters To allow explanatory remarks to be inserted in a program or designate a line label This syntax is different from the R
160. xample below demonstrates this 10 PULSE 0 0 1 05 1 30 A PULSE 0 IF A 0 THEN STOP 40 PRINT A 50 GOTO 30 RUN 03 02 02 02 01 01 01 5E 03 5E 03 5E 03 STOP Operation of a Multiple Pulsed Outputs The real power of the PULSE operation comes when it is combined with the ON INP tasking statement and multiple timed outputs are required The application could involve pneumatic valves injection molding steps or other sequence oriented operations The following lame example simulates a drum timer by turning on outputs when a previous timed pulse is complete The job here is a bag sealing operation A pre heater is started and sealing head is brought down when the start switch is pressed After the pre heater is timed out the heater is turned on for a second The head is down for 4 seconds When the head is done an interrupt is generated which moves the package to the next place Opto rack positions 04 are used to controla sealing head pre heater heater and pusher CONFIG PIO 1 0 0 0 0 0 Detect start switch ON INP 0 0 1 1 GOSUB start Detect emergency or STOP switch on inp 1 0 2 2 gosub emergency Generate interrupt when head goes up on inp 2 2 2 1 GOSUB headup Generate interrupt when pre heat done on inp 3 1 1 2 gosub preheat rest of program Start Start switch was pushed Now start sequence bit 2 4 1 reset bag pusher pulse 0 2 0 2 0 turn on pre heat for 2 seconds pulse 1 2 1 4 0 Bri
161. y SPI chan len data dly in x SQR m START BIT task number START COUNT n START INP n STOP STOP BIT task number STOP COUNT a STOP INPn n STR m a SYS n PRINT TA B m n TAN n a TICK n Purpose Prints string of characters Returns time from pulsed output Pulses an output bit Reads DATA statement values Allows program comments Renumbers program lines Resets read pointer Continues program execution Continues program execution Continues program execution Reenables software counter Resumes execution after GOSUB Resumes execution after interrupt Returns right most p char of m Returns pseudo random number Begins program execution Saves program or data to memory device Returns the sign of m Calculates sine function Outputs square wave at a frequency Communicates with SPI devices some cards only Returns square root Enables a BIT task Activates software counter s Activates port checking task Terminates program execution Disables BIT task Deactivates software counter s Deactivates port checking task Converts m to a string n Accesses system data Tabs to position m Returns the tangent indirectly Return time from 12 hour clock Command Summary 5 Command Summary 6 Command TIME TROFF TRON UNLOCK UNNEW USING VAL VARPTR XOR Syntax n TIME n TIME n TROFF TRON UNLOCK UNNEW USING n VAL m VARPTR variable n a XOR b Purpose Reads calendar clock Writes
162. y a space The space is added by the LIST statement and is not stored in your program OPERATORS Arithmetic Operators CAM BASIC is capable of manipulating single bits within an 8 bit field packed BCD data 8 bit bytes 16 bit words and real floating point numbers CAM BASIC assumes that all numbers contained in a program and those input by the operator are decimal It can also accept hexadecimal numbers The prefix of the number determines its modulus For example Decimal 33797 no prefix needed Hexadecimal amp 8405 amp means hexadecimal Binary 11001001 means binary The output can be in decimal hexadecimal or binary format Decimal 242 Hexadecimal E2 Additional math operators are Operator Operation Example addition X Y subtraction X Y z multiplication X Y division X Y integer division X Y mod modulo X mod Y Expression analysis of multiplication and division is carried out first from left to right Then addition and subtraction are evaluated from left to right NOTE Values for X and Y cannot exceed 32767 or be less than 32768 when performing integer division If these values are exceeded overflow will occur data will be erroneous and no error message will be generated Relational Operators Operator Relation Example Tested equal X Y lt gt not equal X lt gt Y Concepts 9 gt greater than X gt Y lt less than X lt Y gt greater than X gt Y or equal
163. y in a multitasking or time critical program The reason is the print buffer easily fills up halting execution until the buffer is low enough to execute the next line The program will slow down tremendously and not operate on a real time basis none 10 TRON 20 FOR X 30 A X 40 NEXT 50 TROFF RUN 20 30 40 30 40 30 40 30 40 50 none WNHrFR oO 0 TO 3 Commands 135 SYNTAX PURPOSE REMARKS RELATED EXAMPLE ERROR n VAL m To convert a string to a number The VAL function strips leading spaces from m before calculating the result VAL Numeric Function A leading alphanumeric character will always cause zero to be returned regardless of the characters that follow the alphanumeric character Trailing alphanumeric characters are ignored STR ASC CHR PRINT VAL 98 98 PRINT VAL A56 0 PRINT VAL 12BB 12 PRINT VAL LAST 0 none Commands 136 SYNTAX PURPOSE REMARKS VARPTR Numeric Function VARPTR variable To return the address in RAM of the variable This command is similar to VARPTR found in other BASICs Unlike VARPTR the address of a string variable is returned directly variable is any CAMBASIC variable This function may be used to pass data other than single bytes to external machine or assembly language routines It can find uncommitted RAM for temporary data storage Use it to transfer data from arrays to Flash or ex
164. y is located See your hardware manual for more information The type parameter is determined by the display type as shown in the table below Ww Ne o Eo S ZA DP 1x16 DP 2x20 DP 2x40 DP 4x20 LCD 2x20 LCD 2x40 LCD 4x20 LCD 4x40 LCD VF 1 line 16 char line VF 2 line 20 char line VF 2 line 40 char line VF 4 line 20 char line LCD 2 line 20 char line LCD 2 line 40 char line LCD 4 line 20 char line LCD 4 line 40 char line LCD Graphic The cursor parameter sets the cursor type This may not be valid depending upon the display type For DP series displays N cursor not displayed all models cursor displayed 2x40 4x20 For LCD character displays DISPLAY cursor not displayed blinking cursor steady cursor CONFIG Commands 8 EXAMPLE ERROR The example below is for a vacuum florescent 2x20 display It illustrates both continuous updating and periodic updating of the display 500 ON TICK 1 GOSUB 590 510 CONFIG DISPLAY amp 40 3 0 520 DISPLAY REMOTE PROCESSING 530 DISPLAY 3 1 Tick 540 DISPLAY 3 8 550 PRINT 9 USING TICK 0 560 IF TICK 0 gt 110 THEN CLEAR TICK 570 GOTO 540 580 590 INC S IF S 20 THEN S 0 DISPLAY 2 19 DISPLAY 2 S gt 600 DISPLAY 2 S 1 gt 610 DISPLAY 3 8 620 RETURN lt Datanegative gt for all parameters lt Data range gt iftype gt 7 orcursor gt 2 lt Data
165. your PC The resultant Intel hex format data is downloaded by PC SmartLINK into the system RAM You may save your assembly code program to EEPROM along with your BASIC program We suggest that you save your BASIC program first then load your assembly code in the free area on the EEPROM above BASIC SAVING AND LOADING PROGRAMS Saving and loading programs to and from nonvolatile memory is as easy as typing SAVE and LOAD You can download programs through a modem hundreds of miles from the computer Concepts 5 AUTORUN OPERATION Once a program has been stored in nonvolatile memory it can autorun on power up PROTECTING YOUR PROGRAMS You can cause your program to be completely hidden so that it cannot be viewed by unauthorized people Once hidden the program cannot be modified or listed The procedure is very simple Just make the following line the first in your program 10 The three periods tell the runtime executor that the contents are to be hidden WARNING Once hidden the process cannot be reversed We made it that way so that programs would truly be p protected Before hiding a program save a copy on disk VARIABLES More than 25 000 unique variables may be defined for use in CAM BASIC programs Variable names may be up to 40 characters long In order to maximize speed the first and last characters and the length are significant Variables must begin with an alpha character They may contain numbers the un

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