;;;;;;; P3 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 and sends it ; to the computer as an integer value from 0 to 8. ; 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). ; ;;;;;;; Program hierarchy ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; Mainline ; Initial ; PotDisplay ; ReadPot ; TXbyte ; RateDisplay ; FXD0808U ; TXbyte ; 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 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 endc #include ;;;;;;; Macro definitions ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; MOVLF macro literal,dest movlw literal movwf dest 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 PotDisplay ;run the potentiometer read and display functions 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 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 movff ADRESH, POTVALUE ;sends the ADC value to POTVALUE 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 movlw 0x0d ;sends 0x0d to the wreg for ascii conversion call TXbyte ;transmits wreg to the Computer movlw 0x30 ;sends 0x30 to the wreg for ascii conversion addwf SMALLPOT,W ;converts the value to ascii call TXbyte ;transmits wreg to the computer 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 bsf ADCON0,GO_DONE ;initiate Conversation REPEAT_ UNTIL_ ADCON0,GO_DONE == 0 ;wait for completion of conversion 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 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 steps the stepper motor in accordance to the STEPRATE variable ControlStepping movf STEPRATE, W ;Add STEPRATE into the step motor accumulator addwf ACCUM, F IF_ .C. ;If there is an overflow from the accumulator then... 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 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 ;;;;;;; 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 end