;;;;;;; P5 for QwikFlash board ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; ; Name: Shane Connelly ; Name: Grant Lohsen ; Handle: WSCL ; ; PIC18F452's internal clock period is 0.4 microseconds. ; Use Timer2 for a loop time of approximately ten milliseconds (see Figure 16-3) ; with A=16, B=223, C=7 for 24976 internal clock cycles = 9990.4 microseconds. ; Toggle B0 output every ten milliseconds for measuring looptime with scope. ; Step stepper motor at a rate of 100 steps per second. ; Blink "Alive" LED every two seconds. ; Also, the code reads the value of the potentiometer every 1 second ; After it reads the potentiometer, it sets the stepper motor to step n times per ; second where n = 12 * (the potentiometer value from 0-8). You may enter the number ; of steps to take with the keypad, as well as the direction to turn (*: clockwise, ; #: counterclockwise). ; ;;;;;;; Program hierarchy ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; Mainline ; Initial ; PotDisplay ; ReadPot ; TXbyte ; RateDisplay ; FXD0808U ; TXbyte ; Keypad ; ReadKeypad ; SendStrg ; TXbyte ; ResetKeypad ; ControlStepping ; BlinkAlive ; LoopTime ; ;;;;;;; Assembler directives ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; list P=PIC18F452, F=INHX32, C=160, N=0, ST=OFF, MM=OFF, R=DEC, X=ON #include P18F452.inc __CONFIG _CONFIG1H, _HS_OSC_1H ;HS oscillator __CONFIG _CONFIG2L, _PWRT_ON_2L & _BOR_ON_2L & _BORV_42_2L ;Reset __CONFIG _CONFIG2H, _WDT_OFF_2H ;Watchdog timer disabled __CONFIG _CONFIG3H, _CCP2MX_ON_3H ;CCP2 to RC1 (rather than to RB3) __CONFIG _CONFIG4L, _LVP_OFF_4L ;RB5 enabled for I/O ;;;;;;; Variables ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; cblock 0x000 ;Beginning of Access RAM COUNT ALIVECNT ;Counter for blinking "Alive" LED HUNDRED ;Counter for reading the potentiometer value POTVALUE ;Holds the raw potentiometer value SMALLPOT ;Holds the scaled value of the potentiometer STEPRATE ;The rate in steps/second of the stepper motor ACCUM ;The accumulator for the motor NUML ;Low byte of number entered NUMH ;High byte of number entered NUMSTPSL ;Low byte of NUMSTPS and the number of steps to take NUMSTPSH ;High byte of numstps POSH ;High byte of the stepper motor position POSL ;Low byte of the stepper motor position DISP_POS:7 ;Display information for stepper motor position DISP_RATE:4 ;Display information for stepper motor rate DISP_BUF:6 ;Display information for numerical input KEYSTRG:4 ;A 4-byte string to hold digit keycodes entered in succession FLAGS ;The bits of flags are used as state bits DISPLAYNUMH ;High byte of the number to be displayed on the LCD DISPLAYNUML ;Low byte of the number to be displayed on the LCD DISPLAYPOS ;Position of the LCD display number in RAM DISPLAYLEN ;Length of the LCD display number in RAM DISPLAYSIGN ;Sign of the LCD display endc #include ;;;;;;; Macro definitions ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; MOVLF macro literal,dest movlw literal movwf dest endm POINT macro stringname MOVLF high stringname, TBLPTRH MOVLF low stringname, TBLPTRL endm ;;;;;;; Vectors ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; org 0x0000 ;Reset vector goto Mainline org 0x0008 ;High priority interrupt vector goto $ ;Trap org 0x0018 ;Low priority interrupt vector goto $ ;Trap ;;;;;;; Mainline program ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; Mainline call Initial ;Initialize everything LOOP_ btg PORTB,RB0 ;Toggle pin, to support measuring loop time bsf PORTC, RC2 ;Toggle pin to support measuring useful function time ;call ResetKeypad call PotDisplay ;run the potentiometer read and display functions call Keypad call ControlStepping ;control the motor step rate call BlinkAlive ;Blink "Alive" LED bcf PORTC, RC2 ;set the pin low to end timing call LoopTime ;Wait for ten milliseconds to be up ENDLOOP_ ;;;;;;; Initial subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine performs all initializations of variables and registers. Initial MOVLF B'01001110',ADCON1 ;Enable PORTA & PORTE digital I/O pins MOVLF B'01100001',ADCON0 ;Select pot input to ADC MOVLF B'11100001',TRISA ;Set I/O for PORTA MOVLF B'11001100',TRISB ;Set I/O for PORTB MOVLF B'11010000',TRISC ;Set I/O for PORTC MOVLF B'00001111',TRISD ;Set I/O for PORTD MOVLF B'00000100',TRISE ;Set I/O for PORTE MOVLF B'00010000',PORTA ;Turn off all four LEDs driven from PORTA bsf PORTB,RB5 ;Step direction is CW MOVLF B'10110111',T2CON ;Set up Timer2 (10 millisecond looptime) MOVLF 222, PR2 MOVLF 200,ALIVECNT ;set the time/loop MOVLF 100,HUNDRED ;set the time/loop call InitLCD return ;;;;;;; InitLCD subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; Initialize the Optrex 8x2 character LCD. ; First wait for 0.1 second, to get past display's power-on reset time. InitLCD MOVLF 10,COUNT ;Wait 0.1 second REPEAT_ rcall LoopTime ;Call LoopTime 10 times decf COUNT,F UNTIL_ .Z. bcf PORTE,0 ;RS=0 for command POINT LCDstr ;Set up table pointer to initialization string tblrd* ;Get first byte from string into TABLAT REPEAT_ bsf PORTE,1 ;Drive E high movff TABLAT,PORTD ;Send upper nibble bcf PORTE,1 ;Drive E low so LCD will process input rcall LoopTime ;Wait ten milliseconds bsf PORTE,1 ;Drive E high swapf TABLAT,W ;Swap nibbles movwf PORTD ;Send lower nibble bcf PORTE,1 ;Drive E low so LCD will process input rcall LoopTime ;Wait ten milliseconds tblrd+* ;Increment pointer and get next byte movf TABLAT,F ;Is it zero? UNTIL_ .Z. return ;;;;;;;;DisplayC subroutine;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine is called with TBLPTR containing the address of a constant ; display string. It sends the bytes of the string to the LCD. The first ; byte sets the cursor position. The remaining bytes are displayed, beginning ; at that position. ; This subroutine expects a normal one-byte cursor-positioning code, 0xhh, or ; an occasionally used two-byte cursor-positioning code of the form 0x00hh. DisplayC bcf PORTE,0 ;Drive RS pin low for cursor-positioning code tblrd* ;Get byte from string into TABLAT movf TABLAT,F ;Check for leading zero byte IF_ .Z. tblrd+* ;If zero, get next byte ENDIF_ REPEAT_ bsf PORTE,1 ;Drive E pin high movff TABLAT,PORTD ;Send upper nibble bcf PORTE,1 ;Drive E pin low so LCD will accept nibble bsf PORTE,1 ;Drive E pin high again swapf TABLAT,W ;Swap nibbles movwf PORTD ;Write lower nibble bcf PORTE,1 ;Drive E pin low so LCD will process byte rcall T40 ;Wait 40 usec bsf PORTE,0 ;Drive RS pin high for displayable characters tblrd+* ;Increment pointer, then get next byte movf TABLAT,F ;Is it zero? UNTIL_ .Z. return ;;;;;;; DisplayV subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine is called with FSR0 containing the address of a variable ; display string. It sends the bytes of the string to the LCD. The first ; byte sets the cursor position. The remaining bytes are displayed, beginning ; at that position. DisplayV bcf PORTE,0 ;Drive RS pin low for cursor positioning code REPEAT_ bsf PORTE,1 ;Drive E pin high movff INDF0,PORTD ;Send upper nibble bcf PORTE,1 ;Drive E pin low so LCD will accept nibble bsf PORTE,1 ;Drive E pin high again swapf INDF0,W ;Swap nibbles movwf PORTD ;Write lower nibble bcf PORTE,1 ;Drive E pin low so LCD will process byte rcall T40 ;Wait 40 usec bsf PORTE,0 ;Drive RS pin high for displayable characters movf PREINC0,W ;Increment pointer, then get next byte UNTIL_ .Z. ;Is it zero? return ;;;;;;; T40 subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; Pause for 40 microseconds or 40/0.4 = 100 clock cycles. ; Assumes 10/4 = 2.5 MHz internal clock rate. T40 movlw 100/3 ;Each REPEAT loop takes 3 cycles movwf COUNT REPEAT_ decf COUNT,F UNTIL_ .Z. return LCDstr db 0x33,0x32,0x28,0x01,0x0c,0x06,0x00 ;Initialization string for LCD ;;;;;;; LoadBuffer subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine loads data into a buffer formatted correctly for the LCD display. ; It assumes the position of the data is loaded via lfsr 0 LoadBuffer ; movf DISPLAYLEN,W clrf POSTDEC0 ;first set the 0x00 terminator IF_ DISPLAYNUMH,7 == 1 ;check for a negative number negf DISPLAYNUML ;if it is, form the 2s compliment comf DISPLAYNUMH, F IF_ .C. incf DISPLAYNUMH, F ENDIF_ ENDIF_ REPEAT_ movlw 10 ;We need to divide 10 from the the value to produce ;the division movwf BARGB0 ;Store 10 in the B argument of divide (A/B) movff DISPLAYNUMH, AARGB0 ;Store the high byte in the value of A for the divide movff DISPLAYNUML, AARGB1 ;Store the low byte in the value of A for the divide call FXD1608U ;Perform the division function movlw 0x30 ;Load an ASCII adjuster addwf REMB0, W ;To add to the remainder of the division movwf POSTDEC0 ;Move the value into the buffer and decrement the position movff AARGB0, DISPLAYNUMH ;Set the remaining value for further division movff AARGB1, DISPLAYNUML ;Set the remaining value for further division decf DISPLAYLEN,F ;decrement the remaining length IF_ .NZ. movf AARGB0,W iorwf AARGB1,W ENDIF_ UNTIL_ .Z. ;until it becomes zero movf DISPLAYLEN,F ;check the display length to see if we need spaces WHILE_ .NZ. movlw 0x20 movwf POSTDEC0 decf DISPLAYLEN,F ;decrement the remaining length ENDWHILE_ return ;;;;;;; PotDisplay subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine briefly displays a range between 0 and 8 of the Potentiometer. PotDisplay decf HUNDRED,F ;Decrement hundred loop counter and return if not zero IF_ .Z. MOVLF 100,HUNDRED ;Reinitialize BLNKCNT call ReadPot ;sends the potentiometers value to the ADC movf POTVALUE,W ;copies potvalue to the wreg mullw 9 ;multiplies potvalue(in wreg) by 9 movff PRODH, SMALLPOT ;get the upper byte and store it in smallpot movf SMALLPOT, W ; multiply the potentiometer value by 12 to generate the mullw 12 ; motor stepping rate between 0 and 96 (in steps/second) movff PRODL, STEPRATE ;save the stepping rate in variable STEPRATE call RateDisplay ;Show the motor rate on the computer ENDIF_ return ;;;;;;; ReadPot subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine reads the potentiometer and puts the upper byte into ADRESH ReadPot bcf ADCON0,3 ;select pot input to ADC bcf ADCON0,4 ; bcf ADCON1,ADFM ;Left Justify data movlw 15 ;initalize wait loop REPEAT_ ;wait loop for 15 iterations decf WREG, F UNTIL_ .Z. bsf ADCON0,GO_DONE ;initiate Conversation REPEAT_ UNTIL_ ADCON0,GO_DONE == 0 ;wait for completion of conversion movff ADRESH, POTVALUE ;sends the ADC value to POTVALUE return ;return with result in ADRESH ;;;;;;; RateDisplay subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine sends the value of the variable STEPRATE to the computer as ASCII digits RateDisplay movlw 0 movwf DISPLAYNUMH movff STEPRATE,DISPLAYNUML movlw 2 movwf DISPLAYLEN lfsr 0,DISP_RATE+3 call LoadBuffer movlw 0xc0 movwf DISP_RATE lfsr 0,DISP_RATE call DisplayV ;movlw 10 ;We need to divide 10 from the STEPRATE to produce ;an ASCII value to transmit ;movwf BARGB0 ;Store 10 in the B argument of divide (A/B) ;movff STEPRATE, AARGB0 ;Store the step rate in the value of A for the divide ;call FXD0808U ;Perform the division function ;movlw 0x0d ;This sends the loads the carriage return value ;call TXbyte ;And send it to the computer ;movlw 0x30 ;Load an ASCII adjuster ;addwf AARGB0, W ;To add to the integer result of the division ;call TXbyte ;Send this ASCII value to the computer ;movlw 0x30 ;Load an ASCII adjuster ;addwf REMB0, W ;To add to the remainder of the division ;call TXbyte ;Send this ASCII value to the computer return ;;;;;;; TXbyte subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine first waits on the UART if a byte is in the process of being ; sent. Then it sends the content of WREG to the PC. TXbyte REPEAT_ ;If an earlier transmission is still UNTIL_ PIR1,TXIF == 1 ;in progress then wait movwf TXREG ;send new byte from wreg return ;;;;;;; ControlStepping subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine sets the stepper motor speed in accordance to the STEPRATE variable ; Also, this subroutine steps the motor the number of steps specified by the NUMSTPS(H:L) variable ControlStepping movf NUMSTPSL,w ;xor numstpsl with numstpsh to see if it is an overall zero value number iorwf NUMSTPSH, w IF_ .NZ. ;check for non-zero value in xor of NUMSTP(H:L) movf STEPRATE, W ;Add STEPRATE into the step motor accumulator addwf ACCUM, F IF_ .C. ;If there is an overflow from the accumulator then... IF_ NUMSTPSH,7 == 1 ;check for ccw decf POSL,f ;decrement the position IF_ .B. decf POSH, f ENDIF_ bcf PORTB,RB5 ;set direction to CCW incf NUMSTPSL,f ;increment the number of steps left to be taken IF_ .C. incf NUMSTPSH, f ENDIF_ ELSE_ ;check for cw incf POSL,f ;increment the current stepper motor position IF_ .C. incf POSH, f ENDIF_ bsf PORTB,RB5 ;set step direction to CW decf NUMSTPSL,f ;decrement the number of steps left to be taken IF_ .B. decf NUMSTPSH, f ENDIF_ ENDIF_ btg PORTB,RB1 ;Toggle RB1 for motor time measurement bsf PORTB,RB4 ;Set the stepper motor movement bcf PORTB,RB4 ;Clear the stepper motor movement movlw 100 ;Move 100 into WREG for subtraction subwf ACCUM,F ;Subtract 100 to drop the counter down from the overflow movff POSH,DISPLAYNUMH ;Move the position codes into the buffer variables movff POSL,DISPLAYNUML movlw 4 ;Set the display length movwf DISPLAYLEN lfsr 0,DISP_POS+6 ;Move DISP_POS into the register for buffer formatting call LoadBuffer ;Format the buffer movlw 0x81 ;Load the LCD control code movwf DISP_POS movlw 0x20 ;Set a space at the beginning for as a formatting break movwf DISP_POS+1 IF_ POSH,7 == 1 ;Check for a negative number in the position variable (POS) movlw 0x2d ;If it's negative, load a - sign ELSE_ movf POSH,W ;Otherwise, we need to check if its either 0 or over 0 iorwf POSL,W IF_ .NZ. movlw 0x2b ;If positive, use a plus sign ELSE_ movlw 0x20 ;otherwise, load a space ENDIF_ ENDIF_ movwf DISPLAYSIGN ;Set the sign into the beginning of the string lfsr 0,DISP_POS+5 movlw 0x20 ;Check for the first space xorwf POSTDEC0,w REPEAT_ movlw 0x20 ;Loop through the entire code xorwf POSTDEC0,w UNTIL_ .Z. iorwf PREINC0, w movff DISPLAYSIGN, POSTINC0 ;Once the first space is found, add the sign in lfsr 0,DISP_POS call DisplayV ENDIF_ ENDIF_ return ;;;;;;; BlinkAlive subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine briefly blinks the LED next to the PIC every two seconds. BlinkAlive bsf PORTA,RA4 ;Turn off LED decf ALIVECNT,F ;Decrement loop counter and return if not zero IF_ .Z. MOVLF 200,ALIVECNT ;Reinitialize BLNKCNT bcf PORTA,RA4 ;Turn on LED for ten milliseconds every 2 sec ENDIF_ return ;;;;;;; ReadKeypad subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ;Reads the input from the keypad ReadKeypad bsf ADCON0,3 ;select keypad input to ADC bsf ADCON0,4 ; bsf ADCON1,ADFM ;Right Justify Data movlw 15 ;initalize wait loop REPEAT_ ;wait loop for 35 iterations decf WREG, F UNTIL_ .Z. bsf ADCON0,GO_DONE ;initiate Conversation REPEAT_ UNTIL_ ADCON0,GO_DONE == 0 ;wait for completion of conversion return ;return with result in ADRESH ;;;;;;; SendStrg subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine sends keypress values to the computer. SendStrg movlw 0x0d ;This sends the carriage return value call TXbyte ;And send it to the computer movlw 0x0a ;This sends the linefeed value call TXbyte ;And send it to the computer movf SIGN,w ;load sign into wreg call TXbyte ;And send it to the computer lfsr 0, KEYSTRG ;puts address of keystring into memory movf KEYSTRG,w ;loads digit of keystring into wreg REPEAT_ call TXbyte ;And send it to the computer movf PREINC0,W UNTIL_ .Z. movlw 0x0d ;This sends the carriage return value call TXbyte ;And send it to the computer movlw 0x0a ;This sends the linefeed value call TXbyte ;And send it to the computer return ;;;;;;; ResetKeypad subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine clears keypress information. ResetKeypad clrf NUMH ;clear numh variable clrf NUML ;clear numl variable movlw 0x20 movwf KEYSTRG ;clear keystrng locations in ram movwf KEYSTRG+1 movwf KEYSTRG+2 movlw 0x30 movwf KEYSTRG+3 ; call ByteOutBuffer ;lfsr 0,KEYSTRG ;remap the location of keystrng return ;;;;;;; Keypad subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine checks for a new keypress. ; This is done by implementing a statemachine which acts both as a button debouncer ; as well as a check to see if the key has been released (thus a new key is being entered). ; Keypad call ReadKeypad IF_ ADRESH,0 == 1 ;if bit 0 of adresh is 1 then clear bits 0 and 1 of flags bcf FLAGS,0 bcf FLAGS,1 ELSE_ IF_ FLAGS,0 == 0 IF_ FLAGS,1 == 0 ;if FLAGS = 00 bsf FLAGS,0 ;set flags bit 0 to 1 ENDIF_ ELSE_ IF_ FLAGS,1 == 0 ;if FLAGS = 01 bsf FLAGS,1 ;set flags bit 1 to 1 movff ADRESL, TBLPTRL ;copy adresl to tblptrl movlw 0x5f ;put 0x5f into tblptrh movwf TBLPTRH tblrd* ;copies keyvalue of pressed button into tablat movlw 0x2a ;xor the tablat with 2a resulting in a 0 if *(0x2a) is pressed xorwf TABLAT,w IF_ .Z. ;if * is pressed movlw 0x2b ;store + in sign movwf SIGN movf NUML, w ;adds the NUMH:NUML values to the NUMSTPSH:NUMSTPSL values storing in NUMH:NUML addwf NUMSTPSL, f movf NUMH, w addwfc NUMSTPSH,f ; call SendStrg ;sends values to computer call ResetKeypad ;clears numh:numl ELSE_ movlw 0x23 ;23 ;xor the tablat with 23 resulting in a 0 if #(0x23) is pressed xorwf TABLAT,w IF_ .Z. ;if # is pressed movlw 0x2d ;store - in sign movwf SIGN movf NUML, w ;adds the NUMH:NUML values to the NUMSTPSH:NUMSTPSL values storing in NUMH:NUML subwf NUMSTPSL, f movf NUMH, w subwfb NUMSTPSH,f ; call SendStrg ;sends values to computer call ResetKeypad ;clears numh:numl ELSE_ movf NUMH, w IF_ .NZ. call ResetKeypad ;resets the keypad ENDIF_ ;movff TABLAT, POSTINC0 ;store the tablat value in keystrng movff KEYSTRG+1, KEYSTRG movff KEYSTRG+2, KEYSTRG+1 movff KEYSTRG+3, KEYSTRG+2 movff TABLAT, KEYSTRG+3 ;call ByteOutBuffer movf NUML, W ;multiply NUML by 10 storing the result in NUMH:NUML mullw 10 movff PRODH, NUMH movff PRODL, NUML movlw 0x30 ;subtract 0x30 from tablat value subwf TABLAT, w addwf NUML, f ;add tablat value to NUMH:NUML movlw 0 addwfc NUMH,f ENDIF_ call ByteOutBuffer ENDIF_ ENDIF_ ENDIF_ ENDIF_ return ;;;;;;; ByteOutBuffer subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine updates the display for each new keypress. ; ByteOutBuffer movlw 0xc4 ;sets the Cursor position code into the buffer movwf DISP_BUF movlw 0x20 ;this portion of the code removes leading space characters replacing them with zeros xorwf KEYSTRG,w IF_ .Z. movlw 0x30 movwf KEYSTRG movlw 0x20 xorwf KEYSTRG+1,w IF_ .Z. movlw 0x30 movwf KEYSTRG+1 movlw 0x20 xorwf KEYSTRG+2,w IF_ .Z. movlw 0x30 movwf KEYSTRG+2 ENDIF_ ENDIF_ ENDIF_ movlw 0x30 ;this portion of the code removes leading zero characters replacing them with spaces xorwf KEYSTRG,w IF_ .Z. movlw 0x20 movwf KEYSTRG movlw 0x30 xorwf KEYSTRG+1,w IF_ .Z. movlw 0x20 movwf KEYSTRG+1 movlw 0x30 xorwf KEYSTRG+2,w IF_ .Z. movlw 0x20 movwf KEYSTRG+2 ENDIF_ ENDIF_ ENDIF_ movff KEYSTRG, DISP_BUF+1 ;this portion of the code copies the characters stored in the key buffer into the display buffer movff KEYSTRG+1, DISP_BUF+2 movff KEYSTRG+2, DISP_BUF+3 movff KEYSTRG+3, DISP_BUF+4 movlw 0x00 ;terminating the display buffer with a null character movwf DISP_BUF+5 return ;;;;;;; LoopTime subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; When Timer2 rolls over and sets the TMR2IF flag, approximately ten ; milliseconds have passed since the last time the flag was set. The flag ; is cleared and execution returns from the subroutine to the mainline loop. LoopTime REPEAT_ UNTIL_ PIR1,TMR2IF == 1 ;Wait for completion of ten milliseconds bcf PIR1,TMR2IF ;Clear flag return #include #include #include end