TITLE "tempAn.asm" ; 0 - 50C termometer List P=PIC16F684, R=DEC INCLUDE "p16f684.inc" ; data segment CBLOCK 0x20 temp, tempAve:2, cnt, tint ; storage for temp measurement del, n, r, d, tmp ; local variables bcd32, bcd10 ; BCD rep of 10*temp w_save, stat_save ; ISR variables point, scale, button ; decimal point flag temp1, temp2, temp3 ; temp readings for averaging segments:12 ENDC ; code segment PAGE __CONFIG _FCMEN_OFF & _IESO_OFF & _BOD_OFF & _CPD_OFF & _CP_OFF & _MCLRE_OFF & _PWRTE_ON & _WDT_OFF & _INTRC_OSC_NOCLKOUT ORG 0 goto main ORG 4 ; ISR movwf w_save ; save W reg swapf STATUS, w ; save stat reg without movwf stat_save ; changing flags bcf PIR1, 0 ; clear TMR1 interrupt flag ; main ISR body (get temp, round it off, and convert to BCD) decfsz tint, f ; time to check temp? goto ISR_end ; not yet - back to main thread bsf tint, 2 ; update the temp interval cntr. call getTemp ; get temp reading from ADC call computeAve ; average temp readings call bin2bcd ; convert it into BCD ISR_end swapf stat_save, w ; get orig flags in STATUS movwf STATUS swapf w_save, f ; restore the original W swapf w_save, w retfie main ; main code bcf STATUS, RP0 ; activate BANK 0 clrf PORTA ; initialize PORT A clrf PORTC ; initialize PORT C movlw 0x07 movwf CMCON0 ; comparators OFF ; ADC configuration movlw b'00001' movwf ADCON0 ; Left justify, Vdd Vref, AN0, On bsf STATUS, RP0 ; change to BANK 1 movlw 1 movwf ANSEL ^ 0x80 ; make RA0/AN0 analog input movlw b'01110000' ; set ADC Frc clock movwf ADCON1 ^ 0x80 movlw 1 movwf PIE1 ^ 0x80 ; enable TMR1 interrupt movlw b'0001001' movwf TRISA ^ 0x80 ; enable RA0 and RA3 for input clrf TRISC ^ 0x80 ; enable output on RC<5:0> bcf STATUS, RP0 ; back to BANK 0 movlw 4 ; INITIALIZATION movwf tint ; setup temp reading interval (4sec) clrf scale ; scale: 0=C 1=F call initSegments ; initialize 7-seg codes call getTemp ; get the first temp reading movf temp, w movwf temp1 movwf temp2 movwf temp3 movwf n movlw 10 movwf bcd10 ; setup scale (temp in C) call bin2bcd ; initialize temp BCD array ; TMR1 configuration movlw b'10110001' ; TMR1 with 1:8 prescaler movwf T1CON movlw b'11000000' ; enable periferial interrupts movwf INTCON bcf PIR1, 0 ; clear timer interrupt flag loop ; main loop btfss PORTA, 3 ; check C/F button status goto $+3 clrf button ; buton is not pressed - continue goto displayTemp btfsc button, 0 ; button debouncing: goto displayTemp ; button was pressed and not released bsf button, 0 ; button is just presed movf scale, w ; toggle the C/F status sublw 1 movwf scale ; scale = 1 - scale addlw 10 ; W = 10 or 11 to display C/F movwf bcd10 ; setup the scale letter code call bin2bcd ; according to the scale (C/F) displayTemp movlw 6 movwf d ; by setting d=6 we start with swapf bcd32, w ; the leftmost digit andlw 0x0F movwf r ; status flags are not modified btfss STATUS, Z ; do not display the leading 0 call displayDigit decf d, f ; get to the middle digit decf d, f clrf point movf bcd32, w andlw 0x0F movwf r ; we display it in any case movlw 0xF0 andwf bcd10, w btfsc scale, 0 ; Celcius? goto $+3 ; NO -proceed with displaying btfss STATUS, Z ; turn on the decimal point? bsf point, 7 call displayDigit clrf point decf d, f ; get to the fraction digit decf d, f swapf bcd10, w ; get the fraction digit andlw 0x0F movwf r btfsc scale, 0 ; Celcius? goto $+2 ; NO - proceed with displaying btfss STATUS, Z ; skip it if it is 0 call displayDigit decf d, f decf d, f movf bcd10, w ; get the scale (C,F) andlw 0x0F movwf r call displayDigit goto loop ; procedures getTemp ; get temp reading from ADC bsf ADCON0, GO ; start ADC operation btfsc ADCON0, GO ; and wait for its completion goto $-1 movf ADRESH, w ; get higher 8 bits of ADC movwf temp ; current temp reading return computeAve movf temp, w ; get current temp reading movwf tempAve ; compute 10-bit average clrf tempAve+1 ; of last 4 temp readings movf temp1, w addwf tempAve, f ; add temp1 btfsc STATUS, C incf tempAve+1, f movf temp2, w addwf tempAve, f ; add temp2 btfsc STATUS, C incf tempAve+1, f movf temp3, w addwf tempAve, f ; add temp3 btfsc STATUS, C incf tempAve+1, f rrf tempAve+1, f ; divide the sum in n+1:n by 4 rrf tempAve, f ; and round off the quitient rrf tempAve+1, f ; pull bit9 of n into C flag rrf tempAve, f ; add it to n btfsc STATUS, C ; examine (old) bit 1 on n incf tempAve, f ; rounding off movf temp2, w ; slide temp readings movwf temp1 movf temp3, w movwf temp2 movf temp, w movwf temp3 return bin2bcd ; convert tempAve into BCD representation movf tempAve, w btfsc scale, 0 call convert ; convert tempAve into F scale movwf n ; save it in n for processing call div10 ; convert n into bcd32:bcd10. btfsc scale, 0 ; scale = F? goto pack ; YES - skip Celcius processing rlf n, f ; double the quotient rlf r, f ; double the remainder movlw 10 subwf r, w btfss STATUS, C goto $+3 movwf r incf n, f btfsc r, 3 ; add 1 to quotient if incf n, f ; the remainder is 8 (rounding) movlw 0x05 ; replace the decimal digit andwf r, f ; with 0 or 5 btfss STATUS, Z ; 0,2,8 -> 0; 4,6->5 bsf r, 0 pack movlw 0x0F ; clear left nibble in bcd10 andwf bcd10, f swapf r, w ; swap nibbles in r addwf bcd10, f ; decimal digit call div10 ; pack the other two digits of n movf r, w ; into bcd32 movwf bcd32 call div10 swapf r, w addwf bcd32, f return displayDigit ; display digit r at position d movlw b'111001' andwf PORTA, f movf d, w iorwf PORTA, f ; start displaying the digit #d movf r, w ; get parameter to w andlw 0x0F addlw segments movwf FSR ; FSR is a pointer to the digit code movf INDF, w ; w = segments[digit] addwf point, w ; process the decimal point movwf tmp rrf tmp, f rrf tmp, f movwf PORTC ; light on the digit movlw b'11001111' ; processing the two higher bits andwf PORTA, f ; of the 7-seg code movf tmp, w andlw b'00110000' iorwf PORTA, f movlw 4 ; a 4ms delay movwf del call delay return div10 ; computing n = n/10 and r = n%10 movlw 5 movwf cnt ; cnt = 5 movf n, w movwf r ; r = n clrf n ; n = 0 movlw 0xA0 bsf STATUS, C subwf r, f ; loop that executes 5 times btfsc STATUS, C goto $+3 addwf r, f bcf STATUS, C rlf n, f ; C = bit of n/10 movwf tmp rrf tmp, f movf tmp, w ; shift right W decfsz cnt, f ; div is done in 5 loop iterations goto $-10 ; end of loop return initSegments ; set up 7-seg digit codes movlw b'00111111' ; gidit 0 pgfedcba movwf segments+0 movlw b'00000110' ; digit 1 movwf segments+1 movlw b'01011011' ; digit 2 movwf segments+2 movlw b'01001111' ; digit 3 movwf segments+3 movlw b'01100110' ; digit 4 movwf segments+4 movlw b'01101101' ; digit 5 movwf segments+5 movlw b'01111101' ; digit 6 movwf segments+6 movlw b'00000111' ; digit 7 movwf segments+7 movlw b'01111111' ; digit 8 movwf segments+8 movlw b'01101111' ; digit 9 movwf segments+9 movlw b'00111001' ; letter C movwf segments+10 movlw b'01110001' ; letter F movwf segments+11 return delay ; a delay for del milliseconds movlw 200 sublw 1 ; this loop takes 5us*200 = 1ms sublw 0 ; for PIC16F684 @ 4 Mhz btfss STATUS, Z goto $-3 decfsz del, f goto delay return convert ; convert C into F bsf STATUS, RP0 ; switch to bank 1 movwf EEADR ; set address (in Wreg) to read bsf EECON1, RD ; load byte form EEPROM movf EEDAT ^ 0x80, w ; move it to Wreg bcf STATUS, RP0 ; back to bank 0 return ORG 0x2100 ; EEPROM data c2fTable dt 32, 32, 33, 33, 33, 34, 34, 35 dt 35, 35, 36, 36, 36, 37, 37, 37 dt 38, 38, 38, 39, 39, 40, 40, 40 dt 41, 41, 41, 42, 42, 42, 43, 43 dt 44, 44, 44, 45, 45, 45, 46, 46 dt 46, 47, 47, 47, 48, 48, 49, 49 dt 49, 50, 50, 50, 51, 51, 51, 52 dt 52, 53, 53, 53, 54, 54, 54, 55 dt 55, 55, 56, 56, 56, 57, 57, 58 dt 58, 58, 59, 59, 59, 60, 60, 60 dt 61, 61, 62, 62, 62, 63, 63, 63 dt 64, 64, 64, 65, 65, 65, 66, 66 dt 67, 67, 67, 68, 68, 68, 69, 69 dt 69, 70, 70, 71, 71, 71, 72, 72 dt 72, 73, 73, 73, 74, 74, 74, 75 dt 75, 76, 76, 76, 77, 77, 77, 78 dt 78, 78, 79, 79, 80, 80, 80, 81 dt 81, 81, 82, 82, 82, 83, 83, 83 dt 84, 84, 85, 85, 85, 86, 86, 86 dt 87, 87, 87, 88, 88, 89, 89, 89 dt 90, 90, 90, 91, 91, 91, 92, 92 dt 92, 93, 93, 94, 94, 94, 95, 95 dt 95, 96, 96, 96, 97, 97, 98, 98 dt 98, 99, 99, 99, 100, 100, 100, 101 dt 101, 101, 102, 102, 103, 103, 103, 104 dt 104, 104, 105, 105, 105, 106, 106, 107 dt 107, 107, 108, 108, 108, 109, 109, 109 dt 110, 110, 110, 111, 111, 112, 112, 112 dt 113, 113, 113, 114, 114, 114, 115, 115 dt 116, 116, 116, 117, 117, 117, 118, 118 dt 118, 119, 119, 119, 120, 120, 121, 121 dt 121, 122, 122, 122, 123, 123, 123, 124 end