;;;;;;; Variables ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; cblock Bank0RAM ;Temporary storage for STATUS during interrupts

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Jeffrey McLaughlin
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1 TotPrgm2 Senior Design Program for Total Project (LED and Motor Control) Hayden Callender list P=PIC16F877, F=INHX8M, C=160, N=77, ST=OFF, MM=OFF, R=DEC, X=OFF #include P16F877.inc config(_cp_off & _PWRTE_ON & _XT_OSC & _WDT_OFF & _BODEN_OFF) Equates Bank0RAM equ H'20' Start of Bank 0 RAM area MaxCount1 equ 150 Number of loops in half a second for LED MaxCount2 equ 250 Number of loops in half a second for PWM TenMsH equ 13 TenMsL equ 250 Variables cblock Bank0RAM W_TEMP STATUS_TEMP BLNKCNT TEMP Temporary storage for W during interrupts Temporary storage for STATUS during interrupts Loop counter for blinking LEDs every half sec. Temporary variable for BlinkTable subroutine TEMP1 TEMP2 LOOPTIME DESIRED DESIRED2 ACTUAL CENTERTIME LEFTLIMIT RL LL DESIREDDIG DESIREDDIG2 COUNT PULSECOUNT PULSE DUTYCYCLE1 DUTYCYCLE2 DIRECTION PDELAY COUNTH COUNTL COPYD endc Macro definitions MOVLF macro literal,dest movlw literal movwf dest endm MOVFF macro source,dest movf source,w movwf dest endm

2 Vectors org H'000' Reset vector nop nop goto Mainline Branch past tables org H'004' Interrupt vector goto IntService Branch to interrupt service routine BlinkTable subroutine This subroutine reads PORTD and retains only the upper three LED bits. It uses them to access table. It s in W the bits of PORTD to be toggled. BlinkTable MOVFF PORTD,W Copy present state of LEDs to TEMP andlw B' ' Keep only bits to be shifted addwf PCL,F Change PC with PCLATH and offset in W retlw B' ' 0000->0001 forward (initialize) retlw B' ' 0001->0010 to right retlw B' ' 0010->0100 to left retlw B' ' 0011->0001 reinitialize to forward retlw B' ' 0100->1000 to backward retlw B' ' 0101->0001 reinitialize to forward retlw B' ' 0110->0001 reinitialize to forward retlw B' ' 0111->0001 reinitialize to forward retlw B' ' 1000->0001 backward to forward retlw B' ' 1001->0001 reinitialize to forward retlw B' ' 1010->0001 reinitialize to forward retlw B' ' 1011->0001 reinitialize to forward retlw B' ' 1100->0001 reinitialize to forward retlw B' ' 1101->0001 reinitialize to forward retlw B' ' 1110->0001 reinitialize to forward retlw B' ' 1111->0001 reinitialize to forward End of Tables Mainline program Mainline call Initial Initialize everything MainLoop call Blink Blink upper 4 LEDs call LoopTime Force loop time to be ten milliseconds goto MainLoop LED's Blink Routine Initial subroutine This subroutine performs all initializations of variables and registers for LEDs. Initial Set register access to bank 1 MOVLF B' ',ADCON1 Select PORTA pins for ADC or digital I/O MOVLF B' ',TRISA Set I/O for PORTA MOVLF B' ',TRISB Set I/O for PORTB MOVLF B' ',TRISC Set I/O for PORTC clrf TRISD Set I/O for PORTD MOVLF B' ',TRISE Set I/O for PORTE MOVLF 249,PR2 Set up Timer2 for a looptime of 10 ms

3 Set register access back to bank 0 MOVLF B' ',T2CON Finish set up of Timer2 (see page 62) clrf PORTD Turn off LEDs MOVLF B' ',INTCON Enable RB0/INT interrupts (see page 98) Blink subroutine This subroutine blinks a new LED every 1 second. Blink decfsz BLNKCNT,F Decrement loop counter and if not zero goto BlinkEnd movlw MaxCount1 Reinitialize BLNKCNT movwf BLNKCNT call BlinkTable Get bits to change into W xorwf PORTD,F and toggle them into PORTD BlinkEnd LoopTime subroutine This subroutine waits for Timer2 to complete its ten millisecond count sequence. LoopTime Test if head-switch is pressed. If so, go to motor driver code bsf PORTD,5 bsf PORTD,0 btfsc PORTD,5 call Steering If not, continue with blinking LED's btfss PIR1,TMR2IF Check whether ten milliseconds are up goto LoopTime bcf PIR1,TMR2IF Clear flag movlw B' ' Toggle PORTA, bit 5 xorwf PORTA,F for testing loop time Motors' Driver Routine Motor Control duty M1 M2 75% frwd bkwd 25% bkwd frwd 50% stop stop NOTE: Above relative to the wheelchair!!! Steering

4 Steering Turn the contents of PORTD to the COPYD flag before continuing bcf PORTD,5 MOVLW PORTD MOVWF COPYD Initialize ADC Initialize MOVLF 2,DIRECTION initialize Direction to center clrf COUNT MOVLF B' ',TRISA setup PORTA for input MOVLF 0xCF,TRISB set PORTB data direction <0> input clrf TRISB clrf TRISC clrf TRISD clrf OPTION_REG set rising edge counting of Pulse bsf OPTION_REG,6 bcf PIE1,ADIE disable ADC interrupt clrf PORTA clrf PORTB MOVLF B' ',INTCON clrf PORTD MOVLF B' ',ADCON0 clrf ADRESH MOVLF B' ',ADCON1 bcf PIR1,ADIF clear conversion complete flag Initialize PWM InitPWM clrf TRISC set pin as output clrf TRISD movlw B' ' set PWM period movwf PR2 clrf CCPR1L bcf CCP1CON,5 bcf CCP1CON,4 bsf T2CON,2 start timer2 bcf PIR1,TMR2IF clear timer2 over flag bcf PIE1,TMR2IE disable TIMER2 interrupt movlw B' ' start PWM movwf CCP1CON clrf CCPR2L bcf CCP2CON,5 bcf CCP2CON,4 bsf T1CON,2 start timer1

5 bcf PIR1,TMR1IF clear timer1 over flag bcf PIE1,TMR1IE disable TIMER2 interrupt movlw B' ' start PWM movwf CCP2CON Test the bits of PORTD before the headswitch was pressed to let the program determing witch direction the client wishes to travel The test of PORTD will be done through the dummy flag COPYD. btfsc COPYD,0 call MoveFwd btfsc COPYD,1 call MoveRt btfsc COPYD,2 call MoveLt btfsc COPYD,3 call MoveBwd call Stop Move Forward MoveFwd ContFwd bsf PORTD,4 Light Stop LED MOVLF B' ',DUTYCYCLE1 Output M1 w/ duty cycle of 75% MOVLF B' ',DUTYCYCLE2 Output M2 w/ duty cycle of 25% call Delay2 call ContFwd If headswitch is hit again, continue goto Stop else stop Move Right MoveRt ContRt bsf PORTD,4 Light Stop LED MOVLF B' ',DUTYCYCLE1 Output M1 w/ duty cycle of 75% call Delay2 call ContRt If headswitch is hit again, continue goto Stop else stop Move Left MoveLt ContLt bsf PORTD,4 Light Stop LED MOVLF B' ',DUTYCYCLE2 Output M2 w/ duty cycle of 25%

6 call Delay2 call ContLt If headswitch is hit again, continue goto Stop else stop Move Backward MoveBwd ContBwd bsf PORTD,4 Light Stop LED MOVLF B' ',DUTYCYCLE1 Output M1 w/ duty cycle of 25% MOVLF B' ',DUTYCYCLE2 Output M2 w/ duty cycle of 75% call Delay2 call ContBwd If headswitch is hit again, continue goto Stop else stop Stop Stop MOVLF B' ',DUTYCYCLE1 Output M1 w/ duty cycle of 50% MOVLF B' ',DUTYCYCLE2 Output M2 w/ duty cycle of 50% bcf PORTD,4 Clear Stop led bsf PORTD,0 Light Forward led goto Mainline Set PWM SetPWM movwf DUTYCYCLE1 bcf CCP1CON,5 set duty cycle --> following lines btfsc DUTYCYCLE1,7 bsf CCP1CON,5 bcf CCP1CON,4 btfsc DUTYCYCLE1,6 bsf CCP1CON,4 movf DUTYCYCLE1,W movlw B' ' andwf DUTYCYCLE1,W movwf CCPR1L MOVWF DUTYCYCLE2 BCF CCP2CON,5 set duty cycle --> following lines BTFSC DUTYCYCLE2,7 BSF CCP2CON,5 BCF CCP2CON,4 BTFSC DUTYCYCLE2,6 BSF CCP2CON,4 MOVF DUTYCYCLE2,W MOVLW B' ' ANDWF DUTYCYCLE2,W MOVWF CCPR2L Delay Delay

7 nop movlw TenMsH movwf COUNTH movlw TenMsL movwf COUNTL DelayLoop decfsz COUNTL,F goto DelayLoop decfsz COUNTH,F goto DelayLoop Delay2 Delay2 call Delay decfsz PDELAY goto Delay2 nop IntService interrupt service routine This interrupt service routine fields all interrupts. It first sets aside W and STATUS. It assumes that direct addressing will not be used in the mainline code to access Bank 1 addresses (once the Initial subroutine has been executed and interrupts enabled). It polls each possible interrupt source to determine whether it needs service. IntService end

MicroToys Guide: Motors N. Pinckney April 2005

MicroToys Guide: Motors N. Pinckney April 2005 Introduction Three types of motors are applicable to small projects: DC brushed motors, stepper motors, and servo motors. DC brushed motors simply rotate in a direction dependent on the flow of current.