;;;;;;; P8 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. ; Blink "Alive" LED every one seconds. ; LCD is initalized and top line set to Freq Hz ; CCP2CON is set to trigger a high priority interrupt when clocked on pin CCP2/RC1 ; Low priority interupts occur when an overflow in tmr3 occurs ; Every second the measurement is restarted; then .4 seconds of measurement are taken ; and displayed on the LCD with a decimal point in the correct position ; ;;;;;;; Program hierarchy ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; Mainline ; Initial ; InitLCD ; LoopTime ; DisplayC ; T40 ; BlinkAlive ; StartMeasureFreq ; CalculateHz ; FLO2432S ; FPD32 ; FLO2432U ; FPM32 ; Normalize ; FPM32 ; INT3232 ; DecimalDisplay ; FXD2408U ; DisplayV ; T40 ; LoopTime ; ; HiPriISR ; ; LoPriISR ; ;;;;;;; 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 ALIVECNT ;Counter for blinking "Alive" LED MX ;Highest byte of counter for frequency measurement MH ;High byte of counter for frequency measurement ML ;Low byte of counter for frequency measurement NX ;Highest byte of start edge to stop edge time difference NH ;High byte of start edge to stop edge time difference NL ;Low byte of start edge to stop edge time difference AXP ;Exponential value of variable A AX ;Highest byte of generic variable A AH ;High byte of generic variable A AL ;Low byte of generic variable A STARTX ;Highest byte of start time STARTH ;High byte of start time STARTL ;Low byte of start time TMR3X ;Highest byte of timer3 CCPR2X ;Highest byte of CCPR2 FIRSTMEAS ;is this the first measurement BYTESTR:10 ;10 word byte buffer to hold the hex DIGITCOUNT ;digit count for the display COUNT ;used by LCD routines TMP0 ;holds location of decimal from normalize STATUS_TEMP ;temporary variable to hold status during interrupt 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 HiPriISR ;Trap org 0x0018 ;Low priority interrupt vector goto LowPriISR ;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 BlinkAlive ;Blink "Alive" LED IF_ PIE2,CCP2IE == 0 ;if CCP2 is not enabled We use the if in the mainline cause we can movf FIRSTMEAS,F ;and if CCP2 was enabled last cycle through IF_ .Z. movlw 1 ;set FIRSTMEAS indicating last cycle ran through movwf FIRSTMEAS call CalculateHz ;calculate the frequency, in Hz ENDIF_ ENDIF_ bcf PORTC, RC2 ;Toggle pin to support measuring useful function time call LoopTime ;PWM blue LED while waiting for ten milliseconds 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'11010010',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 MOVLF B'00000101',CCP2CON ; capture rising edge of input MOVLF B'10001001',T3CON ;bsf PORTB,RB5 ;Step direction is CW bcf IPR2, TMR3IP ;assign low priority to TMR3 overflow interupt bcf PIR2, TMR3IF ;clear flag for overflow interupt bsf PIE2, TMR3IE ;enable timer3 overflow interupts bsf IPR2, CCP2IP ;assign high priority to TMR3 overflow interupt bcf PIR2, CCP2IF ;clear flag for overflow interupt bsf RCON, IPEN ;enable high.low interupt structure bsf INTCON, GIEL ;enable low priority interupts to cpu bsf INTCON, GIEH ;enable high priority interupts to cpu MOVLF B'10110111',T2CON ;Set up Timer2 (10 millisecond looptime) MOVLF 222, PR2 MOVLF 200, ALIVECNT call InitLCD ;Initialize AFTER setting up LoopTime and ports POINT FirstLine ;output Freq Hz to the top line of the LCD call DisplayC return ;;;;;;; HiPriISR subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine is triggered for the high priority interrupt HiPriISR movf FIRSTMEAS, f ;check for a 1 in first measurement IF_ .NZ. ;if it is a one MOVLF 0, FIRSTMEAS movff CCPR2X,STARTX ;copy the current TMR3X:H:L values into startX:H:L movff CCPR2H,STARTH movff CCPR2L,STARTL ELSE_ ;if it is a 0 incf ML,F ;increment MX:H:L, with carry IF_ .C. incf MH,F IF_ .C. incf MX,F ENDIF_ ENDIF_ ENDIF_ IF_ CCPR2X,6 == 1 ;if approximatly 1 million ticks have occured bcf PIE2, CCP2IE ;disable interrupts from CCP2 input movff CCPR2L,NL ;copy CCPR2L:H to NL:H and TMR3x to NX movff CCPR2H,NH movff CCPR2X,NX movf STARTL, w ;subtract STARTX:H:L from NX:H:L subwf NL, f movf STARTH,w subwfb NH, F movf STARTX,w subwfb NX, f ;ELSE_ ENDIF_ bcf PIR2, CCP2IF ;clear interrupt flag for ccp2if IF_ PIR2,TMR3IF == 1 ;check to see if low priority interrupt was triggered movf CCPR2H,F IF_ .Z. incf TMR3X,F ;increase TMR3X if necessary bcf PIR2,TMR3IF ENDIF_ ENDIF_ movff TMR3X,CCPR2X ;copy TMR3X to CCPR2X retfie FAST ;return from function ;;;;;;; LowPriISR subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine is triggered for the low priority interrupt LowPriISR bcf INTCON,GIEH movff STATUS, STATUS_TEMP ;store status into temporary variable incf TMR3X,F ;increment TMR3X bcf PIR2,TMR3IF ;clear the timer3 flag movff STATUS_TEMP, STATUS ;restore status bsf INTCON,GIEH retfie ;and 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 ;;;;;;; CalculateHz subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine calculates the frequency and displays it on the LCD. CalculateHz movff NX,AARGB0 ;move NX:NH:NL into AARGB0:AARGB1:AARGB2 movff NH,AARGB1 movff NL,AARGB2 call FLO2432U ;convert NX:NH:NL into a floating point number ; movff AEXP,BEXP ;place the floating point representation of N into BARGB0:1:2,BEXP ; movff AARGB0,BARGB0 ; movff AARGB1,BARGB1 ; movff AARGB2,BARGB2 movff AEXP,AXP ;place the floating point representation of N into AX:AH:AL,AXP movff AARGB0,AX movff AARGB1,AH movff AARGB2,AL movff MX,AARGB0 ;convert MX:MH:ML into a floating point number movff MH,AARGB1 movff ML,AARGB2 call FLO2432U ;convert MX:MH:ML into a floating point number movff AXP,BEXP ;move AX:AH:AL,AXP into BARGB0:1:2,EXP movff AX,BARGB0 movff AH,BARGB1 movff AL,BARGB2 call FPD32 ;divide floating point M/N, store result into AARGB movff AEXP,AXP ;place the floating point representation of M/N into AX:AH:AL,AXP movff AARGB0,AX movff AARGB1,AH movff AARGB2,AL MOVLF upper 2500000,AARGB0 ;move 2500000 into AARGB0:1:2 MOVLF high 2500000,AARGB1 MOVLF low 2500000,AARGB2 call FLO2432U ; calculate 2500000 in floating point movff AXP,BEXP ;move AX:AH:AL,AXP into BARGB0:1:2,EXP movff AX,BARGB0 movff AH,BARGB1 movff AL,BARGB2 call FPM32 ;multiply 2500000 by M/N in floating point call Normalize ;normalize the value held by 2500000*M/N call DecimalDisplay ;display this on the LCD return ;;;;;;; DecimalDisplay subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine initializes the bytestr buffer ; converts the number returned from normalize into ascii placing the result into ; the bytestr buffer while inserting the decimal point into the string and calling ; displayv DecimalDisplay lfsr 0, BYTESTR+10 ;load bytestr into the memory MOVLF 0x00, POSTDEC0 ;terminate bytestr buffer MOVLF 7, DIGITCOUNT ;put 7 into digit count so we know when we are in position to put the decimal in REPEAT_ movf TMP0,w ;check to see if this is where the decimal should be xorwf DIGITCOUNT, w IF_ .Z. ;if so enter decimal MOVLF 0x2e, POSTDEC0 ENDIF_ MOVLF 10, BARGB0 ;get the current digit call FXD2408U movf REMB0, W iorlw 0x30 ;convert to ascii movwf POSTDEC0 ;load into bytestr buffer ;movf DIGITCOUNT, f ;are we at the beginning of the number being converted to ascii decf DIGITCOUNT,f ;decrement digitcounter UNTIL_ .Z. MOVLF 0xc0, INDF0 ;load cursor position code call DisplayV ;display lower line return ;;;;;;; StartMeasureFreq subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine initializes the frequency measurement bariables and sets up the timer StartMeasureFreq MOVLF 1, FIRSTMEAS ;indicates this is the first measurement MOVLF 0x2f, TMR3X ;clear the TMR information MOVLF 0x2f, CCPR2X clrf TMR3H clrf TMR3L bcf PIR2,CCP2IF ;clear the interrupt flag for CCP2 clrf MX ;clear the MX:H:L information clrf MH clrf ML bsf PIE2,CCP2IE ;re-enable the CCP2 interrupt 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 ; call StartMeasureFreq ;initate measurement ENDIF_ movlw 100 ;test every second xorwf ALIVECNT,W IF_ .Z. call StartMeasureFreq ;initate measurement ENDIF_ 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 ;;;;;;; Normalize subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;; Normalize subroutine ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; This subroutine normalizes AARG to a floating point representation of its ; decimal equivalent with the decimal point moved to the right of a seven-digit ; number (i.e., a decimal number between 1,000,000 and 9,999,999). It is ; assumed that the decimal equivalent of the actual number is less than ; 9,999,999 and more than 0.1000000. ; The location of the actual decimal point is returned in TMP0 with TMP0=0 ; representing a number with no digits to the left of the decimal point. ; For example, if AARG is initially the floating point representation of ; 12.34567, then this subroutine will return with AARG holding the floating ; point representation of 1234567.X and with TMP0 = 2. Normalize MOVLF high PowTen, TBLPTRH ;Point to first table entry MOVLF low PowTen, TBLPTRL MOVLF 8,TMP0 ;Initialize decimal point position REPEAT_ decf TMP0,F ;Decrement decimal point position IF_ .B. ;If it borrows, then we've gone too far BREAK_ ; so exit the loop ENDIF_ TBLRD*+ movff TABLAT,BEXP ;First move table entry to BARG TBLRD*+ movff TABLAT,BARGB0 TBLRD*+ movff TABLAT,BARGB1 TBLRD*+ movff TABLAT,BARGB2 movf AARGB2,W ;Subtract AARG from power of ten subwf BARGB2,W movf AARGB1,W subwfb BARGB1,W movf AARGB0,W subwfb BARGB0,W movf AEXP,W subwfb BEXP,W UNTIL_ .NC. ;Continue until AARG is larger than power of ten MOVLF high PowTen, TBLPTRH ;Form TBLPTR = PowTen + 4(TMP0) MOVLF low PowTen, TBLPTRL decf TMP0,W ;Use the decimal point position to select bcf STATUS,C ;the power of ten needed rlcf WREG,F rlcf WREG,F addwf TBLPTRL,F ;And point to it in the table clrf WREG addwfc TBLPTRH,F TBLRD*+ ;Now retrieve this power of ten to BARG movff TABLAT,BEXP TBLRD*+ movff TABLAT,BARGB0 TBLRD*+ movff TABLAT,BARGB1 TBLRD*+ movff TABLAT,BARGB2 call FPM32 ;Multiply AARG by this power of ten ; to get a value greater than 1,000,000 ;;;;;;; Need to convert to a four-byte integer because the largest signed three- ;;;;;;; byte number has a decimal value of 8388607 call INT3232 movff AARGB1,AARGB0 ;Keep the lower three bytes movff AARGB2,AARGB1 movff AARGB3,AARGB2 return LCDstr db 0x33,0x32,0x28,0x01,0x0c,0x06,0x00 ;Initialization string for LCD FirstLine db "\x80Freq Hz\x00" ;Freq Hz for first line display PowTen db 0x92,0x74,0x24,0x00 ;Floating point representation of 1000000 db 0x8F,0x43,0x50,0x00 ;100000 db 0x8C,0x1C,0x40,0x00 ;10000 db 0x88,0x7A,0x00,0x00 ;1000 db 0x85,0x48,0x00,0x00 ;100 db 0x82,0x20,0x00,0x00 ;10 db 0x7F,0x00,0x00,0x00 ;1 db 0x7b,0x4c,0xcc,0xcd ;0.1 #include #include end