TITLE "lm_mega.asm" ; controller for LitterMaid Mega LIST P=16F684, R=DEC INCLUDE "p16f684.inc" ERRORLEVEL -302 ; no bank warnings __CONFIG _FCMEN_OFF & _IESO_OFF & _BOD_OFF & _CPD_OFF & _CP_OFF & _MCLRE_OFF & _PWRTE_ON & _WDT_OFF & _INTRC_OSC_NOCLKOUT #define END_sw PORTA,4 ; the END switch #define HOME_sw PORTC,4 ; the HOME switch #define LED 3 ; the status LED #define IR_sens PORTC,2 ; infrared sensor input #define FORW 2 ; motor forwards pin @ PORTA #define REW 5 ; motor reverse pin @ PORTA #define STUCK PORTC,0 ; rake stuck sensor #define BATT PORTC,1 ; low battery sensor #define ATTEMPT 3 ; # of attempts to clean the litter box TIMEOUT EQU 10*60/2 ; 10-minutes timeout after pet used the device CBLOCK 0xF0 ; data segment in common area w_save, stat_save, del:2 petIn ; pet presence indicator counter:2 ; time interval counter attempts ; attempts counter to clean the litter box debounce ; for buttons debouncing ENDC ORG 0 ; code segment goto main ORG 4 ; TMR1 ISR routine movwf w_save ; save Wreg swapf STATUS, w ; save stat reg without movwf stat_save ; changing flags call check4Pet ; check for pet incf counter, f ; increment waiting counter btfsc STATUS, Z ; (16-bit walue) incf counter+1, f ISR_end bcf PIR1, TMR1IF ; clear TMR1 interrupt flag swapf stat_save, w ; get original flags in STATUS movwf STATUS swapf w_save, f ; restore Wreg swapf w_save, w retfie main ;################# STATE 0: initial state after power-up clrf PORTA ; when the PORTA will be set up clrf PORTC movlw 0x07 movwf CMCON0 ; comparators OFF bsf STATUS, RP0 ; switch to BANK 1 clrf ANSEL ^ 0x80 ; all inputs digital movlw b'011000' ; motors off movwf TRISA ^ 0x80 ; configure PORTA for input movlw b'011111' ; enable IR lED movwf TRISC ^ 0x80 ; enable RC5 for intput movlw b'01000001' movwf OSCCON ^ 0x80 ; oscillator freq = 1 MHZ clrf ADCON1 ^ 0x80 ; ADC clock = FOSC/2 movlw 24 movwf PR2 ^ 0x80 ; PWM period 10KHz bsf PIE1, TMR1IE ; enable TMR1 interrupt bcf STATUS, RP0 ; back to BANK 0 clrf INTCON ; enable periferal interrupts bsf INTCON, PEIE ; (needed for TMR1) movlw b'00110101' ; enable TMR1 oscillator with 1:8 prescaler movwf T1CON ; it takes 2 sec for TMR1 to overload movlw b'10001000' ; ADC setup: right justify, movwf ADCON0 ; Vref=Vdd, AN2, On movlw 4 ; enable Timer 2 with 1:1 prescaler movwf T2CON movlw 0x20 ; disable single output PWM movwf CCP1CON ; set 2 lower order bits of duty cycle movlw 0x0C movwf CCPR1L ; setup PWM duty period 50% movlw 0x85 ; load PORTA address movwf FSR clrf attempts goto moveForwards ;################# STATE 1: waiting for pet wait4Pet ; wait for pet clrf petIn bcf PIR1, TMR1IF ; clear TMR1 interrupt flag bsf INTCON, GIE ; enable interrupts globally waitLoop btfsc BATT ; check for battery voltage goto malfunction movf petIn, w ; is pet in? btfsc STATUS, Z goto waitLoop ; NO - keep waiting clrf counter ; wait for 10 seconds to check for pet clrf counter+1 ; presence again movlw 5 ; this eliminates short IR ray interruptions subwf counter, w ; caused by whatever reasons btfss STATUS, Z goto $-3 movf petIn, w ; is pet still in? btfsc STATUS, Z goto waitLoop ; No - ignore the previous check and keep waiting clrf counter ; YES - wait for TIMEOUT letting the pet clrf counter+1 ; do its job wait4Timeout btfsc BATT ; check for battery voltage goto malfunction movlw LOW TIMEOUT subwf counter, w btfss STATUS, Z goto wait4Timeout movlw HIGH TIMEOUT subwf counter+1, w btfss STATUS, Z goto wait4Timeout wait4Leave movf petIn, w btfsc STATUS, Z ; is pet still in? goto startCleaning ; NO - start cleanup movlw LOW 60000 movwf del ; YES - wait another minute for pet movlw HIGH 60000 ; to leave and check again movwf del+1 call delay goto wait4Leave startCleaning clrf attempts ; clear the attempts counter goto moveForwards ; at the beginning of cleaning ;################# STATE 2: move rake forwards to clean the litter box moveForwards ; move rake towards the litter can bcf INTCON, GIE ; disable interrupts globally incf attempts, f ; increment attempts counter btfsc END_sw ; is rake at its end position? goto moveBackwards ; YES - move backwards bcf INDF, REW ; make sure that the rake is not moving back bsf INDF, FORW ; move rake forwards clrf debounce decf debounce, f ; Z=0 is guaranteed bcf debounce, 7 forwLoop btfsc END_sw ; check if the end position is reached decf debounce, f btfsc STATUS, Z goto rakeAtEnd btfsc BATT ; check for battery voltage goto malfunction btfss STUCK ; check if rake is stuck goto forwLoop ; all OK - keep going bcf INDF, FORW ; stop the rake call checkAttempt ; if the function returns, it was not the last one movlw LOW 1000 ; make another attempt after 1 sec delay movwf del movlw HIGH 1000 movwf del+1 call delay goto moveBackwards rakeAtEnd bcf INDF, FORW ; stop the rake movlw LOW 3000 ; delay at the rake end position movwf del ; to let the stuff drop into the cab movlw HIGH 3000 movwf del+1 call delay clrf attempts ; no more attempts are needed goto moveBackwards ; move the rake back home ;################# STATE 3: move rake to home position moveBackwards ; return rake to home position bcf INTCON, GIE ; disable interrupts globally bcf INDF, FORW ; make sure that the rake does not move forwards bsf INDF, REW ; move rake home clrf debounce decf debounce, f ; Z=0 is guaranteed bcf debounce, 7 backLoop btfsc HOME_sw ; chek if home position is reached decf debounce, f btfsc STATUS, Z goto rakeAtHome btfsc BATT ; check for battery voltage goto malfunction btfss STUCK ; check if rake is stuck goto backLoop ; all OK - keep going goto malfunction ; stop service if rake is stuck by going backwards rakeAtHome bcf INDF, REW ; stop the rake movf attempts, w ; attempts counter is non-zero if rake is stuck btfsc STATUS, Z ; in this case we give it another try goto wait4Pet movlw LOW 1000 ; make another attempt after 1 sec delay movwf del movlw HIGH 1000 movwf del+1 call delay goto moveForwards ;################# STATE 4: final state - blink the LED and wait for manual reset malfunction bcf INTCON, GIE ; disable interrupts globally bcf INDF, REW ; make sure that the rake is not moving bcf INDF, FORW movlw 0x87 ; setup for blinking the LED movwf FSR ; FSR points to TRISC movlw 1 << LED xorwf INDF, f ; start blinking LED movlw LOW 500 movwf del ; THIS IS A FINAL STATE movlw HIGH 500 ; EXIT FORM IT IS ONLY POSSIBLE movwf del+1 ; BY RESETTING THE DEVICE call delay ; BY TURNING IT OFF AND ON goto $-7 ;;;;;;;;;;;;;;;;;;;PROCEDURES check4Pet ; check for pet presence and setup petIn variable movlw 0x0C iorwf CCP1CON, f ; enable IR transmitter movlw 1 ; timeout in milliseconds movwf del clrf del+1 call delay ; short delay for the sensor to catch up clrf petIn ; petIn = 1 if pet is in btfss IR_sens ; and 0 otherwise incf petIn, f movlw 0xF0 andwf CCP1CON, f ; disable IR transmitter return checkAttempt ; this function checks if the current attempt movf attempts, w ; number to clear the litter box exceeds sublw ATTEMPT ; the max number of attempts btfss STATUS, C ; if this is not the case, the function returns goto malfunction ; otherwise, the device does to the final state return delay ; a delay for del milliseconds movlw 50 ; delay duration is passed in del (2 bytes) sublw 1 ; this loop takes 20us*50 = 1ms sublw 0 ; for PIC @ 1 Mhz btfss STATUS, Z goto $-3 movf del, w ; decrement delay counter btfsc STATUS, Z decf del+1, f decf del, f movf del, w ; del=0? iorwf del+1, w btfss STATUS, Z goto delay return END