;******************************************************************* ; TEMP.ASM ; Temperature Logging Data Acquisition System ; ; Use with Philips 2322-640-63103 NTC Thermistor R/r=9.0, 10K@25C ; ; Valid range of -50C to +125C. Basic accuracy 2% within the ; range -30C to +80C. ;******************************************************************* ; Target: PIC16C84 ; ; Hardware: ; Port B <> LTN211 Display ; RB7 E : Enable (H->L transition latches data) ; RB6 KeyPad Input ; RB5 Piezo Beeper Output ; ; Port A <> ADC0831 Serial ADC ; RA0 ADC Data (Input) ; RA1 ADC Clock (Output) ; RA2 ADC CS (Output) ; RA3 Alarm Output (LED & Relay) ; ;******************************************************************* ; include "picreg.equ" ; ;******************************************************************** ; Test Program ;********************************************************************* LIST P=16C84 ;Register Defines Temp equ 2E ;temp storage during minus sign functions ADCresult equ 2D ;stores ADC reading ADCCtr equ 2C ;stores count for reading 8 bits from serial ADC MaxTemp equ 2B ;Temp. locations for Min and Max temp MinTemp equ 2A HighAlarm equ 29 ;Current high/low alarm values LowAlarm equ 28 ;Stored as ADC values, not actual temps. Temp2 equ 27 ;temp storage ;Registers for B2_BCD H_Byte equ 20 ;Input (Binary) values L_Byte equ 21 R0 equ 22 ;Output (BCD) values R1 equ 23 R2 equ 24 count equ 26 ;Temp. registers for function B2temp equ 25 ;Registers for Misc. Functions DispChar equ 10 ;Character to display on LCD DelayTemp equ 11 ;Temp Counter for time delay DelayT2 equ 12 ;Counter for LONG time delay TempKey equ 13 ;Temporary key press value AlarmFlag equ 14 ;Bit1=ALARM_ACTIVE ;Constant Defines ADCCLK equ 1 ADCDAT equ 0 ADCCS equ 2 ALARM equ 1 ;PIC Register Location Defines EEDATA equ 8 ;EEPROM register defines EEADR equ 9 EECON1 equ 88 EECON2 equ 89 ;MAIN Program Begins goto main Table addwf PC,1 ;calculate jump table location retlw .50+80 ;location 0 - i.e. ADC reading of 0 retlw .50+80 ;Set BIT 7 for a negative quantity retlw .50+80 retlw .50+80 retlw .49+80 retlw .46+80 retlw .43+80 retlw .40+80 retlw .39+80 retlw .37+80 retlw .35+80 retlw .34+80 retlw .32+80 retlw .31+80 retlw .30+80 retlw .29+80 retlw .27+80 ;location 10h retlw .26+80 retlw .25+80 retlw .24+80 retlw .24+80 retlw .23+80 retlw .22+80 retlw .21+80 retlw .20+80 retlw .19+80 retlw .19+80 retlw .18+80 retlw .17+80 retlw .16+80 retlw .16+80 retlw .15+80 retlw .15+80 ;location 20h retlw .14+80 retlw .13+80 retlw .13+80 retlw .12+80 retlw .12+80 retlw .11+80 retlw .11+80 retlw .10+80 retlw .9+80 retlw .9+80 retlw .8+80 retlw .8+80 retlw .7+80 retlw .7+80 retlw .6+80 retlw .6+80 ;location 30 retlw .5+80 retlw .5+80 retlw .4+80 retlw .4+80 retlw .3+80 retlw .3+80 retlw .2+80 retlw .2+80 retlw .2+80 retlw .1+80 retlw .1+80 retlw .0 retlw .0 retlw .1 retlw .1 retlw .1 ;location 40 retlw .2 retlw .2 retlw .2 retlw .3 retlw .3 retlw .4 retlw .4 retlw .4 retlw .5 retlw .5 retlw .6 retlw .6 retlw .6 retlw .7 retlw .7 retlw .7 ;location 50 retlw .8 retlw .8 retlw .9 retlw .9 retlw .9 retlw .10 retlw .10 retlw .10 retlw .11 retlw .11 retlw .12 retlw .12 retlw .12 retlw .13 retlw .13 retlw .13 ;location 60 retlw .14 retlw .14 retlw .14 retlw .15 retlw .15 retlw .15 retlw .16 retlw .16 retlw .16 retlw .17 retlw .17 retlw .17 retlw .18 retlw .18 retlw .18 retlw .19 ;location 70 retlw .19 retlw .20 retlw .20 retlw .20 retlw .21 retlw .21 retlw .21 retlw .22 retlw .22 retlw .22 retlw .23 retlw .23 retlw .23 retlw .24 retlw .24 retlw .25 ;location 80 retlw .25 retlw .25 retlw .26 retlw .26 retlw .26 retlw .27 retlw .27 retlw .27 retlw .28 retlw .28 retlw .28 retlw .29 retlw .29 retlw .30 retlw .30 retlw .31 ;location 90 retlw .31 retlw .31 retlw .32 retlw .32 retlw .33 retlw .33 retlw .33 retlw .34 retlw .34 retlw .34 retlw .35 retlw .35 retlw .35 retlw .36 retlw .36 retlw .37 ;location A0 retlw .37 retlw .38 retlw .38 retlw .38 retlw .39 retlw .40 retlw .40 retlw .40 retlw .41 retlw .41 retlw .42 retlw .42 retlw .42 retlw .43 retlw .43 retlw .44 ;location B0 retlw .45 retlw .45 retlw .46 retlw .46 retlw .46 retlw .47 retlw .47 retlw .48 retlw .48 retlw .49 retlw .50 retlw .50 retlw .51 retlw .51 retlw .52 retlw .52 ;location C0 retlw .53 retlw .53 retlw .54 retlw .55 retlw .55 retlw .56 retlw .56 retlw .57 retlw .57 retlw .58 retlw .59 retlw .60 retlw .61 retlw .61 retlw .62 retlw .62 ;location D0 retlw .63 retlw .64 retlw .65 retlw .66 retlw .66 retlw .67 retlw .68 retlw .69 retlw .70 retlw .71 retlw .72 retlw .73 retlw .73 retlw .74 retlw .76 retlw .77 ;location E0 retlw .78 retlw .80 retlw .81 retlw .82 retlw .83 retlw .85 retlw .86 retlw .87 retlw .89 retlw .91 retlw .92 retlw .94 retlw .96 retlw .98 retlw .100 retlw .105 ;location F0 retlw .107 retlw .110 retlw .112 retlw .115 retlw .120 retlw .125 retlw .125 retlw .126 ;End of Table (F8) main movlw b'01000000' ;Port B all outputs except RB6 tris Port_B movlw 0 ;All Outputs LOW movwf Port_B movlw b'00000001' ;RA0 input, RA1-RA4 outputs tris Port_A movlw b'00000100' ;All Outputs LOW except ADC /CS high movwf Port_A bsf Port_B,5 call Delay ;Wait for LCD to power-up and beep bcf Port_B,5 call LCD_Init call ReadADC ;Initialize Min and Max temps to current movfw ADCresult movwf MaxTemp movwf MinTemp clrf AlarmFlag ;Set Alarm OFF movlw 1 ;Initialize HIGH and LOW alarms from EEPROM call ReadEE ;W now contains data in EEPROM location 1 movwf HighAlarm movlw 2 ;Select EEPROM address 2 call ReadEE ;W now contains data in EEPROM location 2 movwf LowAlarm mainloop call LCD_Cls call ReadADC ;Update MIN and MAX temps movfw MaxTemp subwf ADCresult,0 ;check if max temp exceeded btfss STATUS,C goto NotNewMax movfw ADCresult movwf MaxTemp NotNewMax movfw MinTemp subwf ADCresult,0 ;check if under min temp btfsc STATUS,C goto NotNewMin movfw ADCresult movwf MinTemp NotNewMin ;Display current temperature movlw 80 ;Top Line movwf DispChar call LCD_Cmd movlw 'T' ;Display "TEMP=" movwf DispChar call LCD_Chr movlw 'E' movwf DispChar call LCD_Chr movlw 'M' movwf DispChar call LCD_Chr movlw 'P' movwf DispChar call LCD_Chr movlw '=' movwf DispChar call LCD_Chr movfw ADCresult ;Display current temp and "C" call DisplayTemp movlw 'C' movwf DispChar call LCD_Chr bcf AlarmFlag,ALARM ;Turn off alarm flag movfw HighAlarm subwf ADCresult,0 ;check if high alarm exceeded btfss STATUS,C goto NoHighAlarm bsf AlarmFlag,ALARM ;set alarm flag ON movlw 8B ;End of Top Line movwf DispChar call LCD_Cmd movlw 'A' ;Display "ALARM" movwf DispChar call LCD_Chr movlw 'L' movwf DispChar call LCD_Chr movlw 'A' movwf DispChar call LCD_Chr movlw 'R' movwf DispChar call LCD_Chr movlw 'M' movwf DispChar call LCD_Chr NoHighAlarm movfw LowAlarm subwf ADCresult,0 ;check if low alarm exceeded btfsc STATUS,C goto NoLowAlarm bsf AlarmFlag,ALARM ;set alarm flag ON movlw 8B ;End of Top Line movwf DispChar call LCD_Cmd movlw 'A' ;Display "ALARM" movwf DispChar call LCD_Chr movlw 'L' movwf DispChar call LCD_Chr movlw 'A' movwf DispChar call LCD_Chr movlw 'R' movwf DispChar call LCD_Chr movlw 'M' movwf DispChar call LCD_Chr NoLowAlarm ;Display min and max temperatures movlw b'11000000' ;Bottom Line movwf DispChar call LCD_Cmd movlw 'M' ;Display "MIN=" movwf DispChar call LCD_Chr movlw 'I' movwf DispChar call LCD_Chr movlw 'N' movwf DispChar call LCD_Chr movlw '=' movwf DispChar call LCD_Chr movfw MinTemp call DisplayTemp movlw b'11001000' ;Bottom Line movwf DispChar call LCD_Cmd movlw 'M' ;Display "MAX=" movwf DispChar call LCD_Chr movlw 'A' movwf DispChar call LCD_Chr movlw 'X' movwf DispChar call LCD_Chr movlw '=' movwf DispChar call LCD_Chr movfw MaxTemp call DisplayTemp btfsc AlarmFlag,ALARM ;Check if Alarm is ON, if so, Beep 1 sec bsf Port_B,5 call OneSecDly bcf Port_B,5 ;Turn off beeper btfsc AlarmFlag,1 ;Check if Alarm is ON, if so Light LED goto AlmLedOn bcf Port_A,3 ;LED Off goto AlmLedOff AlmLedOn bsf Port_A,3 AlmLedOff ;Display High and Low Alarm Values movlw b'11000000' ;Bottom Line movwf DispChar call LCD_Cmd movlw 'H' ;Display "HI =" movwf DispChar call LCD_Chr movlw 'I' movwf DispChar call LCD_Chr movlw ' ' movwf DispChar call LCD_Chr movlw '=' movwf DispChar call LCD_Chr movfw HighAlarm call DisplayTemp movlw b'11001000' ;Bottom Line movwf DispChar call LCD_Cmd movlw 'L' ;Display "LOW=" movwf DispChar call LCD_Chr movlw 'O' movwf DispChar call LCD_Chr movlw 'W' movwf DispChar call LCD_Chr movlw '=' movwf DispChar call LCD_Chr movfw LowAlarm call DisplayTemp btfsc AlarmFlag,ALARM ;Check if Alarm is ON, if so, Beep 1 sec bsf Port_B,5 call OneSecDly bcf Port_B,5 ;Turn off beeper goto mainloop ;KeyPad Scan Function ;Returns either 0 in w (no key pressed) or 1-4 in w for key pressed ;Fully debounced, waits for key release ScanKey call TestKey movwf Temp2 btfss Temp2,7 ;Is w still null? (i.e. is bit 7 still set) goto WaitForRls movlw 0 ;Nothing found, clear to return WaitForRls movwf TempKey WaitKeyLoop call TestKey movwf Temp2 btfss Temp2,7 ;Is w still null? (i.e. is bit 7 still set) goto WaitKeyLoop ;Key still down .... wait for release movfw TempKey ;Put Key Return Value into w return ;KeyPad Non-debounced Scan Function ;Returns either 0 in w (no key pressed) or 1-4 in w for key pressed ;No debounce, active on key press ScanKey2 call TestKey movwf Temp2 btfss Temp2,7 ;Is w still null? (i.e. is bit 7 still set) return ;w must contain 1-4 movlw 0 ;Nothing found, clear to return ;Return bit 7 high if no key pressed or 1-4 in w for key pressed TestKey movlw 0 ;Make Port_B all low movwf Port_B movlw 80 ;Pre-Load w with bit 7 high bsf Port_B,0 ;Make Key 1 row HIGH btfsc Port_B,6 ;Check if key 1 pressed movlw .1 bcf Port_B,0 bsf Port_B,1 ;Make Key 2 row HIGH btfsc Port_B,6 ;Check if key 2 pressed movlw .2 bcf Port_B,1 bsf Port_B,2 ;Make Key 3 row HIGH btfsc Port_B,6 ;Check if key 3 pressed movlw .4 bcf Port_B,2 bsf Port_B,3 ;Make Key 4 row HIGH btfsc Port_B,6 ;Check if key 4 pressed movlw .8 bcf Port_B,3 return ModeSet ModeSetHi call ShortDelay call LCD_Cls movlw 'S' ;Display "SET HIGH ALARM" movwf DispChar call LCD_Chr movlw 'E' movwf DispChar call LCD_Chr movlw 'T' movwf DispChar call LCD_Chr movlw ' ' movwf DispChar call LCD_Chr movlw 'H' movwf DispChar call LCD_Chr movlw 'I' movwf DispChar call LCD_Chr movlw 'G' movwf DispChar call LCD_Chr movlw 'H' movwf DispChar call LCD_Chr movlw ' ' movwf DispChar call LCD_Chr movlw 'A' movwf DispChar call LCD_Chr movlw 'L' movwf DispChar call LCD_Chr movlw 'A' movwf DispChar call LCD_Chr movlw 'R' movwf DispChar call LCD_Chr movlw 'M' movwf DispChar call LCD_Chr movlw b'11000000' ;Bottom Line movwf DispChar call LCD_Cmd movlw 'H' ;Display "HI =" movwf DispChar call LCD_Chr movlw 'I' movwf DispChar call LCD_Chr movlw ' ' movwf DispChar call LCD_Chr movlw '=' movwf DispChar call LCD_Chr movfw HighAlarm call DisplayTemp call ScanKey2 ;Check if a key is pressed movwf Temp2 btfsc Temp2,0 ;If Key 1, go to next MODE (Set Low Alm) goto ModeSetLow btfsc Temp2,1 ;If "+", Increment HIGH alarm Value incf HighAlarm btfsc Temp2,2 ;If "-", Decrement HIGH alarm Value decf HighAlarm goto ModeSetHi ModeSetLow call ShortDelay call LCD_Cls movlw 'S' ;Display "SET LOW ALARM" movwf DispChar call LCD_Chr movlw 'E' movwf DispChar call LCD_Chr movlw 'T' movwf DispChar call LCD_Chr movlw ' ' movwf DispChar call LCD_Chr movlw 'L' movwf DispChar call LCD_Chr movlw 'O' movwf DispChar call LCD_Chr movlw 'W' movwf DispChar call LCD_Chr movlw ' ' movwf DispChar call LCD_Chr movlw 'A' movwf DispChar call LCD_Chr movlw 'L' movwf DispChar call LCD_Chr movlw 'A' movwf DispChar call LCD_Chr movlw 'R' movwf DispChar call LCD_Chr movlw 'M' movwf DispChar call LCD_Chr movlw b'11000000' ;Bottom Line movwf DispChar call LCD_Cmd movlw 'L' ;Display "LO =" movwf DispChar call LCD_Chr movlw 'O' movwf DispChar call LCD_Chr movlw ' ' movwf DispChar call LCD_Chr movlw '=' movwf DispChar call LCD_Chr movfw LowAlarm call DisplayTemp call ScanKey2 ;Check if a key is pressed movwf Temp2 btfsc Temp2,0 ;If Key 1, go to next MODE (Clr Min/Max) goto ModeSetClr btfsc Temp2,1 ;If "+", Increment LOW alarm Value incf LowAlarm btfsc Temp2,2 ;If "-", Decrement LOW alarm Value decf LowAlarm goto ModeSetLow ModeSetClr call ShortDelay call LCD_Cls movlw 'C' ;Display "CLEAR MIN/MAX" movwf DispChar call LCD_Chr movlw 'L' movwf DispChar call LCD_Chr movlw 'E' movwf DispChar call LCD_Chr movlw 'A' movwf DispChar call LCD_Chr movlw 'R' movwf DispChar call LCD_Chr movlw ' ' movwf DispChar call LCD_Chr movlw 'M' movwf DispChar call LCD_Chr movlw 'I' movwf DispChar call LCD_Chr movlw 'N' movwf DispChar call LCD_Chr movlw '/' movwf DispChar call LCD_Chr movlw 'M' movwf DispChar call LCD_Chr movlw 'A' movwf DispChar call LCD_Chr movlw 'X' movwf DispChar call LCD_Chr movlw '?' movwf DispChar call LCD_Chr movlw b'11000000' ;Bottom Line movwf DispChar call LCD_Cmd movlw 'P' ;Display "PRESS + TO CLR" movwf DispChar call LCD_Chr movlw 'R' movwf DispChar call LCD_Chr movlw 'E' movwf DispChar call LCD_Chr movlw 'S' movwf DispChar call LCD_Chr movlw 'S' movwf DispChar call LCD_Chr movlw ' ' movwf DispChar call LCD_Chr movlw '+' movwf DispChar call LCD_Chr movlw ' ' movwf DispChar call LCD_Chr movlw 'T' movwf DispChar call LCD_Chr movlw 'O' movwf DispChar call LCD_Chr movlw ' ' movwf DispChar call LCD_Chr movlw 'C' movwf DispChar call LCD_Chr movlw 'L' movwf DispChar call LCD_Chr movlw 'R' movwf DispChar call LCD_Chr call ScanKey ;Check if a key is pressed movwf Temp2 btfsc Temp2,0 ;If Key 1, go to next MODE (Done) goto ModeSetDone btfsc Temp2,1 ;If "+", Increment LOW alarm Value goto ClrMinMax goto ModeSetClr ClrMinMax call ReadADC ;Initialize Min and Max temps to current movfw ADCresult movwf MaxTemp movwf MinTemp ModeSetDone call ShortDelay movf HighAlarm,w ;Save HIGH and LOW alarms to EEPROM movwf Temp movlw 1 call WriteEE ;Write Hi Alarm to EEPROM location 1 movf LowAlarm,w movwf Temp movlw 2 call WriteEE ;Write Lo Alarm to EEPROM location 2 return ;Delay Functions for display (approx. 1 second) OneSecDly movlw .8 movwf Temp DDelay decfsz Temp,1 goto DelayIt return DelayIt call LongDelay call ScanKey ;Check if a key is pressed movwf Temp2 btfsc Temp2,0 ;If Key 1, go to MODE operation call ModeSet goto DDelay ;******************************************************************* ; Internal functions ;******************************************************************* ;** Read one byte from the ADC and store it in ADCresult ReadADC movlw 0 ; Clear out ADCresult register for new data movwf ADCresult bcf Port_A,ADCCS ; Activate /CS line on the ADC to start movlw 9 ; Set number of bits to read in = 8 +1 start movwf ADCCtr ; Load this into the counter register bsf Port_A,ADCCLK ; Pulse the ADC clock line High then Low nop ; signals the start of a conversion bcf Port_A,ADCCLK Get_One_Loop ; This is the main loop, should execute 9 times bsf Port_A,ADCCLK ; Pulse the ADC clock line hight then low nop ; to get the first bit bcf Port_A,ADCCLK btfsc Port_A,ADCDAT ; Check the value of the data bit goto SetCarry bcf STATUS,C ; If its a zero, put a zero into the Carry goto RotateBits SetCarry bsf STATUS,C ; Otherwise its a 1, put that into the carry RotateBits rlf ADCresult ; Shift bits left from carry into ADReslt decfsz ADCCtr ; Decrement Counter - goto Get_One_Loop ; Do it 9 times bsf Port_A,ADCCS ; When done, Disable the ADC ;LIMIT max reading if necessary movlw .248 ;limit reading of ADC to F8 to prevent subwf ADCresult,0 ;going past last entry in jump table btfss STATUS,C return movlw .248 ;limit the ADC reading at end of jump table movwf ADCresult return ;** Convert and Display a temperature at the current display location DisplayTemp call Table ;goto jump table for alarm Celcius Temperature movwf L_Byte ;load data for BCD display btfss L_Byte,7 ;Test bit 7 (is it a negative number?) goto NotNeg movlw .45 ;ASCII minus sign movwf DispChar call LCD_Chr bcf L_Byte,7 ;Convert to non-negative number NotNeg clrf H_Byte call B2_BCD ;convert to BCD ;Display R1 lo movfw R1 andlw b'00001111' btfsc STATUS,Z ;Remove leading zeroes goto BlankOne addlw 30 ;Turn into an ASCII digit movwf DispChar call LCD_Chr BlankOne ;Display R2 hi then R2 lo swapf R2,0 andlw b'00001111' addlw 30 ;Turn into an ASCII digit movwf DispChar call LCD_Chr movfw R2 andlw b'00001111' addlw 30 ;Turn into an ASCII digit movwf DispChar call LCD_Chr movlw ' ' ;Trailing blank to clear display movwf DispChar call LCD_Chr return ;ReadEE: Reads a byte from the EEPROM of the PIC16C84 ; Parameters: location in EEPROM (0-63dec) in W ; Returns: byte read in W register ReadEE movwf EEADR ;Put desired address into EEADR bsf STATUS,RP0 ;Select Register Page 1 bsf EECON1,0 ;RD operation flag bcf STATUS,RP0 ;Select Register Page 0 again movf EEDATA,W ;Read data, put into W register return ;WriteEE: Writes a byte to the EEPROM of the PIC16C84 ; Parameters: location in EEPROM (0-63dec) in W ; data to be written in location 'Temp' ; Note: Value in Temp is destroyed during write operation WriteEE: movwf EEADR ;Put desired address into EEADR movf Temp,W ;Put data to be written into EEDATA movwf EEDATA movf INTCON,W ;Store old interrupt status in Temp movwf Temp bcf INTCON,7 ;Turn off all interrupts bsf STATUS,RP0 ;Select Register Page 1 bsf EECON1,2 ;Write Enable flag movlw 55h ;Required sequence to write to EEPROM movwf EECON2 movlw b'10101010' movwf EECON2 bsf EECON1,1 ;WR operation flag EEIsBusy btfsc EECON1,1 ;Wait for BUSY flag to end goto EEIsBusy bcf EECON1,2 ;Disable Write Enable flag bcf STATUS,RP0 ;Select Register Page 0 again movf Temp,w ;Reset interrupts to original state movwf INTCON return ;******************************************************************* ; LTN211 16 char by 2 LCD display functions for PICPROTO ;******************************************************************* LCD_Init ;Initialize LTN211 LCD display movlw 33 ;Output 0x33 to LCD movwf DispChar call LCD_Cmd movlw 32 ;Output 0x32 to LCD movwf DispChar call LCD_Cmd movlw 28 ;Output 0x28 to LCD movwf DispChar ; 4 bit mode call LCD_Cmd movlw 0C ;Output 0x0C to LCD movwf DispChar ; Display ON, Cursor&Blink Off call LCD_Cmd movlw 06 ;Output 0x06 to LCD movwf DispChar ; Entry Mode: AutoIncrement call LCD_Cmd call LCD_Cls return LCD_Cls ;Clear LCD display screen, home cursor movlw 01 ;Output 0x01 to LCD movwf DispChar ; Clear Display call LCD_Cmd movlw 02 ;Output 0x02 to LCD movwf DispChar ; Home Cursor call LCD_Cmd call Delay call Delay return LCD_L2 ;Set cursor to start of LCD line 2 movlw b'11000000' movwf DispChar ; Set Display Cursor to Line 2 call LCD_Cmd call Delay call Delay call Delay return LCD_Cmd ;Send a command to the LCD display swapf DispChar,0 ;Put upper nibble into lower of W andlw b'00001111' ;Mask off upper nibble movwf Port_B bsf Port_B,7 ;Toggle Enable HIGH then LOW again call Delay call Delay bcf Port_B,7 call Delay call Delay movfw DispChar ;send lower nibble to display andlw b'00001111' ;Mask off upper nibble movwf Port_B bsf Port_B,7 ;Toggle Enable HIGH then LOW again call Delay call Delay bcf Port_B,7 call Delay call Delay ;? return LCD_Chr ;Send a Character to the LCD display swapf DispChar,0 ;Put upper nibble into lower of W andlw b'00001111' ;Mask off upper nibble movwf Port_B bsf Port_B,4 ;Set bit 4 (Register Select) HIGH bsf Port_B,7 ;Toggle Enable HIGH then LOW again bcf Port_B,7 movfw DispChar ;send lower nibble to display andlw b'00001111' ;Mask off upper nibble movwf Port_B bsf Port_B,4 ;Set bit 4 (Register Select) HIGH bsf Port_B,7 ;Toggle Enable HIGH then LOW again bcf Port_B,7 call Delay call Delay ;? return LongDelay ;Approx. 125 mS delay movlw .255 movwf DelayT2 ldelaya call Delay decfsz DelayT2,1 goto ldelaya return ShortDelay ;Approx. 25 mS delay movlw .51 movwf DelayT2 sdelaya call Delay decfsz DelayT2,1 goto sdelaya return Delay ;0.6ms delay for LCD initialization movlw .250 ;Load Temp with constant for .3 ms movwf DelayTemp delaya decfsz DelayTemp,1 ;Dec until zero goto delaya movlw .250 ;Load Temp with constant for .3 ms movwf DelayTemp delayb decfsz DelayTemp,1 ;Dec until zero goto delayb return ;******************************************************************* ; Binary to BCD Converter ; ; Input: Two bytes of RAM; L_Byte, H_Byte ; Output: Three bytes of RAM; R0, R1, R2 ; ; Usage: Put value into L_Byte and H_Byte, call B2_BCD, result in ; R2 is LSD and R1 is MSD: Four digits (nibbles) in 2 bytes ; Lower 4 bits of LSD are least sig. digit, upper 4 are 2nd ; digit. ;******************************************************************* B2_BCD bcf STATUS,0 ;Clear carry bit movlw .16 movwf count ;Set counter to 16 clrf R0 clrf R1 clrf R2 loop16 rlf L_Byte rlf H_Byte rlf R2 rlf R1 rlf R0 decfsz count goto adjDEC RETLW 0 adjDEC movlw R2 movwf FSR call adjBCD movlw R1 movwf FSR call adjBCD movlw R0 movwf FSR call adjBCD goto loop16 adjBCD movlw 3 addwf 0,W movwf B2temp btfsc B2temp,3 ;Test if result > 7 movwf 0 movlw 30 addwf 0,w movwf B2temp btfsc B2temp,7 ;Test if result > 7 movwf 0 ;Save as MSD RETLW 0 ;******************************************************************* END