TITLE "LCD direct drive" List P=16F916, R=DEC INCLUDE "p16F916.inc" SCL EQU 7 ; Clock line setup SDA EQU 6 ; Data line setup ; data segment in the shared area CBLOCK 0x70 tempC:2, tens, units, tempOld displayCodes:2, mode, testL err_i2c, dataIO, ACK_NAK, cnt ; I2C interface vars ENDC PAGE __CONFIG _DEBUG_OFF & _FCMEN_OFF & _IESO_OFF & _BOD_OFF & _CPD_OFF & _CP_OFF & _MCLRE_OFF & _PWRTE_ON & _WDT_ON & _INTOSCIO org 0 btfss STATUS, NOT_TO goto loop goto main codeUr addwf PCL, f retlw b'00001111' ; right part of digit 0 retlw b'00001100' ; right part of digit 1 retlw b'00001011' ; right part of digit 2 retlw b'00001110' ; right part of digit 3 retlw b'00001100' ; right part of digit 4 retlw b'00000110' ; right part of digit 5 retlw b'00000111' ; right part of digit 6 retlw b'00001100' ; right part of digit 7 retlw b'00001111' ; right part of digit 8 retlw b'00001110' ; right part of digit 9 retlw b'00000000' ; the "-" symbol codeUl addwf PCL, f retlw b'01100000' ; left part of digit 0 retlw b'00000000' ; left part of digit 1 retlw b'01010000' ; left part of digit 2 retlw b'01010000' ; left part of digit 3 retlw b'00110000' ; left part of digit 4 retlw b'01110000' ; left part of digit 5 retlw b'01110000' ; left part of digit 6 retlw b'01000000' ; left part of digit 7 retlw b'01110000' ; left part of digit 8 retlw b'01110000' ; left part of digit 9 retlw b'00010000' ; the "- symbol codeTr addwf PCL, f retlw b'10010000' ; right part of digit 0 retlw b'10000000' ; right part of digit 1 retlw b'10100000' ; right part of digit 2 retlw b'10100000' ; right part of digit 3 retlw b'10110000' ; right part of digit 4 retlw b'00110000' ; right part of digit 5 retlw b'00110000' ; right part of digit 6 retlw b'10000000' ; right part of digit 7 retlw b'10110000' ; right part of digit 8 retlw b'10110000' ; right part of digit 9 retlw b'00100000' ; the "-" symbol retlw b'00000000' ; blank codeTl addwf PCL, f retlw b'10001110' ; left part of digit 0 retlw b'00000010' ; left part of digit 1 retlw b'10001100' ; left part of digit 2 retlw b'10000110' ; left part of digit 3 retlw b'00000010' ; left part of digit 4 retlw b'10000110' ; left part of digit 5 retlw b'10001110' ; left part of digit 6 retlw b'10000010' ; left part of digit 7 retlw b'10001110' ; left part of digit 8 retlw b'10000110' ; left part of digit 9 retlw b'00000000' ; the "-" symbol retlw b'00000000' ; blank main bsf STATUS, RP0 ; change to BANK 1 movlw 7 movwf CMCON0 ; comparators off clrf ANSEL ^ 0x80 ; all inputs digital clrf OSCCON ^ 0x80 ; oscillator configuration bits clrf TRISA ^ 0x80 ; STEP 1 clrf TRISB ^ 0x80 clrf TRISC ^ 0x80 bcf STATUS, RP0 bsf STATUS, RP1 ; change to BANK 2 bsf LCDCON ^ 0x100, VLCDEN ; STEP 2: enable LCD bias voltage pins bsf LCDCON ^ 0x100, CS1 ; STEP 3: select clock source (lfintosc) bcf LCDCON ^ 0x100, CS0 bcf LCDCON ^ 0x100, LMUX1 ; STEP 4: select multiplex mode (static) bcf LCDCON ^ 0x100, LMUX0 bcf LCDPS, WFT ; STEP 5: select waveform type (A) bcf LCDPS, BIASMD ; STEP 6: select Bias mode bcf LCDPS, LP3 ; STEP 7: select refresh rate bc LCDPS, LP2 ; 1:3 bsf LCDPS, LP1 bcf LCDPS, LP0 movlw b'10111111' ; step 8: enable LCD segment lines movwf LCDSE0 movlw 0xFF movwf LCDSE1 clrf LCDDATA0 ^ 0x100 ; step 9: clear segment data registers clrf LCDDATA1 ^ 0x100 bsf LCDCON ^ 0x100, LCDEN ; step 10: turn on the LCD driver module bcf LCDCON ^ 0x100, SLPEN ; enable LCD in sleep mode movlw b'00001010' movwf WDTCON ; watchdog timer prescaler 1:1024 bcf STATUS, RP1 ; back to BANK 0 ; setup the temp sensor resolution of 0.0625C and shutdown call start_I2C movlw b'10010000' ; address byte movwf dataIO call write_I2C ; send address byte movlw 1 movwf dataIO ; config pointer call write_I2C movlw b'01100001' movwf dataIO ; temp resolution call write_I2C call stop_I2C clrf tempOld clrf mode loop ; MAIN LOOP btfss mode, 0 goto getTemp clrwdt call getTemp1 ; mode 0: request new temp conversion incf mode, f sleep nop getTemp clrwdt call getTemp2 ; get temp from sensor incf mode, f movf tempOld, w subwf tempC, w btfss STATUS, Z ; old temp = new one? call displayTemp ; NO - update display sleep nop goto loop displayTemp clrf displayCodes clrf displayCodes+1 call temp2BCD movwf tens ; extract tens and units movwf units swapf tens, f movlw 0x0F andwf tens, f andwf units, f dispTens movf tens, w ; displaying tens call codeTr iorwf displayCodes, f movf tens, w call codeTl iorwf displayCodes+1, f dispUnits movf units, w ; displaying units call codeUr iorwf displayCodes, f movf units, w call codeUl iorwf displayCodes+1, f movf displayCodes+1, w ; update LCD movwf LCDDATA1 ^ 0x100 movf displayCodes, w movwf LCDDATA0 ^ 0x100 bcf STATUS, RP1 ; back to BANK 0 return start_I2C ; start setup for I2C interface movlw 0x85 ; setup FSR to point to TRISA movwf FSR movlw b'00111111' andwf PORTA, f bsf INDF, SDA ; pull high SDA and SCL bsf INDF, SCL goto $+1 ; delay slot bcf INDF, SDA ; set data low nop ; wait for slave to detect it bcf INDF, SCL ; set clock low return stop_I2C ; stop setup for I2C interface movlw b'00111111' andwf PORTA, f bcf INDF, SCL ; make sure that clock and data bcf INDF, SDA ; lines are low nop bsf INDF, SCL ; release clock line nop bsf INDF, SDA ; release data line return write_I2C ; write byte to I2C line movlw b'00111111' andwf PORTA, f bcf INDF, SCL ; make sure that clock is low clrf err_i2c ; start with no error movlw 8 movwf cnt ; bits counter w_loop bcf INDF, SDA ; start w. data bit low rlf dataIO, f ; get the rightmost data bit btfss STATUS, C bcf INDF, SDA ; now the data bit is on the line btfsc STATUS, C bsf INDF, SDA goto $+1 bsf INDF, SCL ; raise clock up nop bcf INDF, SCL ; ... and low decfsz cnt, f goto w_loop ; repeat this 8 times bsf INDF, SDA ; check ACK from slave goto $+1 ; let slave respond bsf INDF, SCL ; clock up btfsc PORTA, SDA ; check the ACK from slave incf err_i2c, f ; no ACK (error) bcf INDF, SCL ; clock down return read_I2C ; read byte from I2C line movlw b'00111111' andwf PORTA, f bcf INDF, SCL ; make sure that clock is low movlw 8 movwf cnt ; bits counter r_loop bcf INDF, SCL ; set clock low for long enough goto $+1 bsf INDF, SCL ; set clock high bcf STATUS, C btfsc PORTA, SDA bsf STATUS, C ; C = data bit rlf dataIO, f ; insert it into the data byte decfsz cnt, f goto r_loop ; repeat this 8 times bcf INDF, SCL ; sending the ACK/NAK to slave bsf INDF, SDA movf ACK_NAK, f ; the NAK signal btfsc STATUS, Z bcf INDF, SDA ; the ACK signal nop bsf INDF, SCL ; raise clock up nop bcf INDF, SCL ; ... and low nop bsf INDF, SDA ; release the data line return getTemp1 ; request TEMP conversion call start_I2C movlw b'10010000' ; address byte movwf dataIO call write_I2C ; send address byte movlw 1 movwf dataIO ; config pointer call write_I2C movlw b'11100001' ; request one-shot temp conv movwf dataIO ; temp resolution call write_I2C call stop_I2C return getTemp2 ; read TEMP from sensor call start_I2C movlw b'10010000' ; address byte/W movwf dataIO call write_I2C ; send address byte clrf dataIO ; TEMP register pointer call write_I2C call start_I2C movlw b'10010001' ; address byte/R movwf dataIO call write_I2C ; send address byte clrf ACK_NAK call read_I2C ; get TEMP high order byte movf dataIO, w movwf tempC incf ACK_NAK, f ; setup to send NAK signal call read_I2C ; get TEMP low order byte movf dataIO, w movwf tempC+1 call stop_I2C test movlw 0xB0 ; round off tempC is the fractional addwf tempC+1, w ; part in tempC+1 is above 5 btfss STATUS, C return rounding btfsc tempC, 7 ; tempC < 0 ? goto negative incf tempC, f ; rounding off non-negative temp return negative decf tempC, f ; rounding off negative temp return temp2BCD movf tempC, w movwf tempOld ; update old temp bsf STATUS, RP1 ; switch to BANK 2 movwf EEADRL ; set address (in Wreg) to read bsf STATUS, RP0 ; switch to BANK 3 bcf EECON1, EEPGD bsf EECON1, RD ; load byte form EEPROM bcf STATUS, RP0 ; back to BANK 2 movf EEDATL, w ; move it to Wreg return testLCD ; this function is for testing only movlw -9 ; it displays on the LCD the numbers movwf testL ; in the range -9 .. 100 ; this way one can test the 7-segment lcdLoop ; codes and the BCD conversion movf testL, w movwf tempC call displayTemp movlw 255 ; short delay addlw -1 goto $+1 goto $+1 btfss STATUS, Z goto $-4 incf testL, f movlw 101 subwf testL, w btfsc STATUS, Z goto testLCD goto lcdLoop return ORG 0x2100 ; conversion table dt 0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7 dt 0xB8, 0xB9, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15 dt 0x16, 0x17, 0x18, 0x19, 0x20, 0x21, 0x22, 0x23 dt 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x30, 0x31 dt 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39 dt 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47 dt 0x48, 0x49, 0x50, 0x51, 0x52, 0x53, 0x54, 0x55 dt 0x56, 0x57, 0x58, 0x59, 0x60, 0x61, 0x62, 0x63 dt 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x70, 0x71 dt 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79 dt 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87 dt 0x88, 0x89, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95 dt 0x96, 0x97, 0x98, 0x99, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA dt 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xA9 dt 0xA8, 0xA7, 0xA6, 0xA5, 0xA4, 0xA3, 0xA2, 0xA1 END