Post by thread:[PICLIST] Initialising an HD44780 compatible LCD

part 0 44 bytes his is a multi-part message in MIME format. part 1 553 bytes content-type:text/plain; charset=us-ascii (decoded 7bit) "Haris I. Volos" wrote: > > Hi! > > I am a beginner in PIC and I have built a specific circuit that features a > 16x2 LCD which is connected to a 16F877 pic running at 4MHz. Did some work on that a while back, and have been using the code, but haven't looked at it for a while, so it's a bit unfamiliar. However, the 2 attachments lm0321.asm I got from somewhere. lcd.asm is my version of it. It does work. check your ports for data and commands and change if necessary regards Howard. part 2 20300 bytes content-type:text/plain; charset=us-ascii; (decoded 7bit) LIST P=16C64 ERRORLEVEL -302 ; ; This program interfaces to a Hitachi (LM032L) 2 line by 20 character display ; module. The program assembles for either 4-bit or 8-bit data interface, depending ; on the value of the 4bit flag. LCD_DATA is the port which supplies the data to ; the LM032L, while LCD_CNTL is the port that has the control lines ( E, RS, RW ). ; In 4-bit mode the data is transfer on the high nibble of the port ( PORT<7:4> ). ; ; Program = LM032L.ASM ; Revision Date: 5-10-94 ; 1-22-97 Compatibility with MPASMWIN 1.40 ; ; include <p16c64.inc> ADCON1 EQU 9F FALSE EQU 0 TRUE EQU 1 include <lm032l.h> ; Four_bit EQU TRUE ; Selects 4- or 8-bit data transfers Data_HI EQU FALSE ; If 4-bit transfers, Hi or Low nibble of PORT ; ; if ( Four_bit && !Data_HI ) ; LCD_DATA EQU PORTB LCD_DATA_TRIS EQU TRISB ; else ; LCD_DATA EQU PORTD LCD_DATA_TRIS EQU TRISD ; endif ; LCD_CNTL EQU PORTA ; ; ; ; LCD Display Commands and Control Signal names. ; if ( Four_bit && !Data_HI ) ; E EQU 0 ; LCD Enable control line RW EQU 1 ; LCD Read/Write control line RS EQU 2 ; LCD Register Select control line ; else ; E EQU 3 ; LCD Enable control line RW EQU 2 ; LCD Read/Write control line RS EQU 1 ; LCD Register Select control line ; endif ; ; TEMP1 EQU 0x030 ; org RESET_V ; RESET vector location RESET GOTO START ; ; ; This is the Periperal Interrupt routine. Should NOT get here ; page org ISR_V ; Interrupt vector location PER_INT_V ERROR1 BCF STATUS, RP0 ; Bank 0 BSF PORTC, 0 BCF PORTC, 0 GOTO ERROR1 ; ; ; START ; POWER_ON Reset (Beginning of program) CLRF STATUS ; Do initialization (Bank 0) CLRF INTCON CLRF PIR1 BSF STATUS, RP0 ; Bank 1 MOVLW 0x00 ; The LCD module does not like to work w/ weak pull-ups MOVWF OPTION_REG ; CLRF PIE1 ; Disable all peripheral interrupts MOVLW 0xFF ; MOVWF ADCON1 ; Port A is Digital. ; ; BCF STATUS, RP0 ; Bank 0 CLRF PORTA ; ALL PORT output should output Low. CLRF PORTB CLRF PORTC CLRF PORTD CLRF PORTE BCF T1CON, TMR1ON ; Timer 1 is NOT incrementing ; BSF STATUS, RP0 ; Select Bank 1 CLRF TRISA ; RA5 - 0 outputs MOVLW 0xF0 ; MOVWF TRISB ; RB7 - 4 inputs, RB3 - 0 outputs CLRF TRISC ; RC Port are outputs BSF TRISC, T1OSO ; RC0 needs to be input for the oscillator to function CLRF TRISD ; RD Port are outputs CLRF TRISE ; RE Port are outputs BSF PIE1, TMR1IE ; Enable TMR1 Interrupt BSF OPTION_REG,NOT_RBPU ; Disable PORTB pull-ups BCF STATUS, RP0 ; Select Bank 0 ; page ; ; Initilize the LCD Display Module ; CLRF LCD_CNTL ; ALL PORT output should output Low. DISPLAY_INIT if ( Four_bit && !Data_HI ) MOVLW 0x02 ; Command for 4-bit interface low nibble endif ; if ( Four_bit && Data_HI ) MOVLW 0x020 ; Command for 4-bit interface high nibble endif ; if ( !Four_bit ) MOVLW 0x038 ; Command for 8-bit interface endif ; MOVWF LCD_DATA ; BSF LCD_CNTL, E ; BCF LCD_CNTL, E ; ; ; This routine takes the calculated times that the delay loop needs to ; be executed, based on the LCD_INIT_DELAY EQUate that includes the ; frequency of operation. These uses registers before they are needed to ; store the time. ; LCD_DELAY MOVLW LCD_INIT_DELAY ; MOVWF MSD ; Use MSD and LSD Registers to Initilize LCD CLRF LSD ; LOOP2 DECFSZ LSD, F ; Delay time = MSD * ((3 * 256) + 3) * Tcy GOTO LOOP2 ; DECFSZ MSD, F ; END_LCD_DELAY GOTO LOOP2 ; ; ; Command sequence for 2 lines of 5x7 characters ; CMD_SEQ ; if ( Four_bit ) if ( !Data_HI ) MOVLW 0X02 ; 4-bit low nibble xfer else MOVLW 0X020 ; 4-bit high nibble xfer endif ; else ; 8-bit mode MOVLW 0X038 endif ; MOVWF LCD_DATA ; This code for both 4-bit and 8-bit modes BSF LCD_CNTL, E ; BCF LCD_CNTL, E ; ; if ( Four_bit ) ; This code for only 4-bit mode (2nd xfer) if ( !Data_HI ) MOVLW 0x08 ; 4-bit low nibble xfer else MOVLW 0x080 ; 4-bit high nibble xfer endif MOVWF LCD_DATA ; BSF LCD_CNTL, E ; BCF LCD_CNTL, E ; endif ; ; Busy Flag should be valid after this point ; MOVLW DISP_ON ; CALL SEND_CMD ; MOVLW CLR_DISP ; CALL SEND_CMD ; MOVLW ENTRY_INC ; CALL SEND_CMD ; MOVLW DD_RAM_ADDR ; CALL SEND_CMD ; ; page ; ;Send a message the hard way movlw 'M' call SEND_CHAR movlw 'i' call SEND_CHAR movlw 'c' call SEND_CHAR movlw 'r' call SEND_CHAR movlw 'o' call SEND_CHAR movlw 'c' call SEND_CHAR movlw 'h' call SEND_CHAR movlw 'i' call SEND_CHAR movlw 'p' call SEND_CHAR movlw B'11000000' ;Address DDRam first character, second line call SEND_CMD ;Demonstration of the use of a table to output a message movlw 0 ;Table address of start of message dispmsg movwf TEMP1 ;TEMP1 holds start of message address call Table andlw 0FFh ;Check if at end of message (zero btfsc STATUS,Z ;returned at end) goto out call SEND_CHAR ;Display character movf TEMP1,w ;Point to next character addlw 1 goto dispmsg out loop goto loop ;Stay here forever ; ; INIT_DISPLAY MOVLW DISP_ON ; Display On, Cursor On CALL SEND_CMD ; Send This command to the Display Module MOVLW CLR_DISP ; Clear the Display CALL SEND_CMD ; Send This command to the Display Module MOVLW ENTRY_INC ; Set Entry Mode Inc., No shift CALL SEND_CMD ; Send This command to the Display Module RETURN ; page ; ;******************************************************************* ;* The LCD Module Subroutines * ;******************************************************************* ; if ( Four_bit ) ; 4-bit Data transfers? ; if ( Data_HI ) ; 4-bit transfers on the high nibble of the PORT ; ;******************************************************************* ;*SendChar - Sends character to LCD * ;*This routine splits the character into the upper and lower * ;*nibbles and sends them to the LCD, upper nibble first. * ;******************************************************************* ; SEND_CHAR MOVWF CHAR ;Character to be sent is in W CALL BUSY_CHECK ;Wait for LCD to be ready MOVF CHAR, w ANDLW 0xF0 ;Get upper nibble MOVWF LCD_DATA ;Send data to LCD BCF LCD_CNTL, RW ;Set LCD to read BSF LCD_CNTL, RS ;Set LCD to data mode BSF LCD_CNTL, E ;toggle E for LCD BCF LCD_CNTL, E SWAPF CHAR, w ANDLW 0xF0 ;Get lower nibble MOVWF LCD_DATA ;Send data to LCD BSF LCD_CNTL, E ;toggle E for LCD BCF LCD_CNTL, E RETURN ; else ; 4-bit transfers on the low nibble of the PORT ; ;******************************************************************* ;* SEND_CHAR - Sends character to LCD * ;* This routine splits the character into the upper and lower * ;* nibbles and sends them to the LCD, upper nibble first. * ;* The data is transmitted on the PORT<3:0> pins * ;******************************************************************* ; SEND_CHAR MOVWF CHAR ; Character to be sent is in W CALL BUSY_CHECK ; Wait for LCD to be ready SWAPF CHAR, W ANDLW 0x0F ; Get upper nibble MOVWF LCD_DATA ; Send data to LCD BCF LCD_CNTL, RW ; Set LCD to read BSF LCD_CNTL, RS ; Set LCD to data mode BSF LCD_CNTL, E ; toggle E for LCD BCF LCD_CNTL, E MOVF CHAR, W ANDLW 0x0F ; Get lower nibble MOVWF LCD_DATA ; Send data to LCD BSF LCD_CNTL, E ; toggle E for LCD BCF LCD_CNTL, E RETURN ; endif else ; ;***************************************************************** ;* SEND_CHAR - Sends character contained in register W to LCD * ;* This routine sends the entire character to the PORT * ;* The data is transmitted on the PORT<7:0> pins * ;***************************************************************** ; SEND_CHAR MOVWF CHAR ; Character to be sent is in W CALL BUSY_CHECK ; Wait for LCD to be ready MOVF CHAR, w MOVWF LCD_DATA ; Send data to LCD BCF LCD_CNTL, RW ; Set LCD in read mode BSF LCD_CNTL, RS ; Set LCD in data mode BSF LCD_CNTL, E ; toggle E for LCD BCF LCD_CNTL, E RETURN ; endif ; page ; ;******************************************************************* ;* SendCmd - Sends command to LCD * ;* This routine splits the command into the upper and lower * ;* nibbles and sends them to the LCD, upper nibble first. * ;* The data is transmitted on the PORT<3:0> pins * ;******************************************************************* ; if ( Four_bit ) ; 4-bit Data transfers? ; if ( Data_HI ) ; 4-bit transfers on the high nibble of the PORT ; ;******************************************************************* ;* SEND_CMD - Sends command to LCD * ;* This routine splits the command into the upper and lower * ;* nibbles and sends them to the LCD, upper nibble first. * ;******************************************************************* SEND_CMD MOVWF CHAR ; Character to be sent is in W CALL BUSY_CHECK ; Wait for LCD to be ready MOVF CHAR,w ANDLW 0xF0 ; Get upper nibble MOVWF LCD_DATA ; Send data to LCD BCF LCD_CNTL,RW ; Set LCD to read BCF LCD_CNTL,RS ; Set LCD to command mode BSF LCD_CNTL,E ; toggle E for LCD BCF LCD_CNTL,E SWAPF CHAR,w ANDLW 0xF0 ; Get lower nibble MOVWF LCD_DATA ; Send data to LCD BSF LCD_CNTL,E ; toggle E for LCD BCF LCD_CNTL,E RETURN ; else ; 4-bit transfers on the low nibble of the PORT ; SEND_CMD MOVWF CHAR ; Character to be sent is in W CALL BUSY_CHECK ; Wait for LCD to be ready SWAPF CHAR, W ANDLW 0x0F ; Get upper nibble MOVWF LCD_DATA ; Send data to LCD BCF LCD_CNTL, RW ; Set LCD to read BCF LCD_CNTL, RS ; Set LCD to command mode BSF LCD_CNTL, E ; toggle E for LCD BCF LCD_CNTL, E MOVF CHAR, W ANDLW 0x0F ; Get lower nibble MOVWF LCD_DATA ; Send data to LCD BSF LCD_CNTL, E ; toggle E for LCD BCF LCD_CNTL, E RETURN ; endif else ; ;************************************************************** ;* SEND_CND - Sends command contained in register W to LCD * ;* This routine sends the entire character to the PORT * ;* The data is transmitted on the PORT<7:0> pins * ;************************************************************** SEND_CMD MOVWF CHAR ; Command to be sent is in W CALL BUSY_CHECK ; Wait for LCD to be ready MOVF CHAR, w MOVWF LCD_DATA ; Send data to LCD BCF LCD_CNTL, RW ; Set LCD in read mode BCF LCD_CNTL, RS ; Set LCD in command mode BSF LCD_CNTL, E ; toggle E for LCD BCF LCD_CNTL, E RETURN ; endif ; page ; if ( Four_bit ) ; 4-bit Data transfers? ; if ( Data_HI ) ; 4-bit transfers on the high nibble of the PORT ; ;******************************************************************* ;* This routine checks the busy flag, returns when not busy * ;* Affects: * ;* TEMP - Returned with busy/address * ;******************************************************************* ; BUSY_CHECK BSF STATUS, RP0 ; Select Register page 1 MOVLW 0xFF ; Set Port_D for input MOVWF LCD_DATA_TRIS BCF STATUS, RP0 ; Select Register page 0 BCF LCD_CNTL, RS ; Set LCD for Command mode BSF LCD_CNTL, RW ; Setup to read busy flag BSF LCD_CNTL, E ; Set E high BCF LCD_CNTL, E ; Set E low MOVF LCD_DATA, W ; Read upper nibble busy flag, DDRam address ANDLW 0xF0 ; Mask out lower nibble MOVWF TEMP BSF LCD_CNTL, E ; Toggle E to get lower nibble BCF LCD_CNTL, E SWAPF LCD_DATA, w ; Read lower nibble busy flag, DDRam address ANDLW 0x0F ; Mask out upper nibble IORWF TEMP ; Combine nibbles BTFSC TEMP, 7 ; Check busy flag, high = busy GOTO BUSY_CHECK ; If busy, check again BCF LCD_CNTL, RW BSF STATUS, RP0 ; Select Register page 1 MOVLW 0x0F MOVWF LCD_DATA_TRIS ; Set Port_D for output BCF STATUS, RP0 ; Select Register page 0 RETURN ; else ; 4-bit transfers on the low nibble of the PORT ; ;******************************************************************* ;* This routine checks the busy flag, returns when not busy * ;* Affects: * ;* TEMP - Returned with busy/address * ;******************************************************************* ; BUSY_CHECK BSF STATUS, RP0 ; Bank 1 MOVLW 0xFF ; Set PortB for input MOVWF LCD_DATA_TRIS BCF STATUS, RP0 ; Bank 0 BCF LCD_CNTL, RS ; Set LCD for Command mode BSF LCD_CNTL, RW ; Setup to read busy flag BSF LCD_CNTL, E ; Set E high BCF LCD_CNTL, E ; Set E low SWAPF LCD_DATA, W ; Read upper nibble busy flag, DDRam address ANDLW 0xF0 ; Mask out lower nibble MOVWF TEMP ; BSF LCD_CNTL, E ; Toggle E to get lower nibble BCF LCD_CNTL, E MOVF LCD_DATA, W ; Read lower nibble busy flag, DDRam address ANDLW 0x0F ; Mask out upper nibble IORWF TEMP, F ; Combine nibbles BTFSC TEMP, 7 ; Check busy flag, high = busy GOTO BUSY_CHECK ; If busy, check again BCF LCD_CNTL, RW BSF STATUS, RP0 ; Bank 1 MOVLW 0xF0 ; MOVWF LCD_DATA_TRIS ; RB7 - 4 = inputs, RB3 - 0 = output BCF STATUS, RP0 ; Bank 0 RETURN ; endif else ; ;************************************************************** ;* This routine checks the busy flag, returns when not busy * ;* Affects: * ;* TEMP - Returned with busy/address * ;************************************************************** ; BUSY_CHECK BSF STATUS,RP0 ; Select Register page 1 MOVLW 0xFF ; Set port_D for input MOVWF LCD_DATA_TRIS BCF STATUS, RP0 ; Select Register page 0 BCF LCD_CNTL, RS ; Set LCD for command mode BSF LCD_CNTL, RW ; Setup to read busy flag BSF LCD_CNTL, E ; Set E high BCF LCD_CNTL, E ; Set E low MOVF LCD_DATA, w ; Read busy flag, DDram address MOVWF TEMP BTFSC TEMP, 7 ; Check busy flag, high=busy GOTO BUSY_CHECK BCF LCD_CNTL, RW BSF STATUS, RP0 ; Select Register page 1 MOVLW 0x00 MOVWF LCD_DATA_TRIS ; Set port_D for output BCF STATUS, RP0 ; Select Register page 0 RETURN ; endif page ; Table addwf PCL, F ;Jump to char pointed to in W reg retlw 'M' retlw 'i' retlw 'c' retlw 'r' retlw 'o' retlw 'c' retlw 'h' retlw 'i' retlw 'p' retlw ' ' retlw 'T' retlw 'e' retlw 'c' retlw 'h' retlw 'n' retlw 'o' retlw 'l' retlw 'o' retlw 'g' retlw 'y' Table_End retlw 0 ; if ( (Table & 0x0FF) >= (Table_End & 0x0FF) ) MESSG "Warning - User Definded: Table Table crosses page boundry in computed jump" endif ; end part 3 7869 bytes content-type:text/plain; charset=us-ascii; (decoded 7bit) ;definitions #define rs porta,0 ;output to lcd #define rw porta,1 ;output to lcd #define e porta,2 ;output to lcd #define lcd portc ;output to LCD ;Data is lower nibble #define zflag status,2 ;zero flag #define cflag status,0 ;carry flag ;setup porta for digital movlw b'00000110' ;(adcon1 is in bank 1) movwf adcon1 ;setup porta as digital on all pins (0 to 5) ; ;setup porta directions movlw b'011000' ; movwf trisa ;setup portb clrf portb movlw b'11111111' ;portb, hi nibble sec code. lwr nibble laser card buttons movwf trisb ;setup portc clrf portc movlw b'11000000' ;portc movwf trisc ;bits 6,7 must both be inputs for usart ;************** WATCH ******************* ;in busy_check, trisc is changed. be sure change doesn't affect bits 6 7 ;**************************************** ;rest of setup ============================================================ call initlcd ;initilises lcd - has to be run once ============================================================ ;to send a command - load "char" with the command - call lcd_cmd ;to send a character (letter) - load "char" with the character (eltter) ;and call lcd_char ;============================================================ initlcd ;============================================================ ;4 bits data is in lower nibble of lcd (portc) ;display control 0000 1 d c b ;d is 1=display on, 0=display off. c is 1=cursor on, 0=cursor off. ;b is 1 = blinking, 0 = not ;Entry Mode Set. 0000 0 1 i/d s ;i/d 1 = Address increments, 0 = decrements. s 1 = display shifts 0 = display does not shift ;(display shift is when the display scrolls left or right, depending on i/d) ;return home, clear display ;------------------ bcf e ;e line lo bcf rw ;read/write line lo bcf rs ;rs line lo ;*** movlw b'00000011' ;4 bit data flow command movwf lcd ;following sequence between ***'s bsf e ;has to be followed bcf e ;to initilise LCD to 4 bit mode call tmr_125u call tmr_5m ;wait for more than 4.1 mS call tmr_5m movlw b'00000011' movwf lcd bsf e bcf e call tmr_125u ;wait for 125 uS movlw b'00000011' movwf lcd bsf e bcf e call tmr_125u ;wait for 125 uS movlw b'00000010' ;note this is 00000010 not 00000011 movwf lcd bsf e bcf e ;4 bits from here on call tmr_125u ;*** movlw b'00101000' ;4 bits 2 lines 5x8 movwf char call lcd_cmd ; movlw b'00001111' ;display on, cursor on, blinking on ; movlw b'00001110' ;display on, cursor on, blinking off movlw b'00001100' ;display on, cursor off, blinking off movwf char call lcd_cmd movlw b'00000001' ;clear display movwf char call lcd_cmd movlw b'00000110' ;cursor move by inc. no display shift movwf char ;what's the fuck this mean? call lcd_cmd call tmr_5m ;long delay to allow call tmr_5m ;lcd to settle itself call tmr_5m call tmr_5m return ;=============================================================================== ;============================================================================ lcd_char ;character to be sent is in char ;============================================================================ call busy_check ; Wait for LCD to be ready ;send hi nibble first. port uses lo nibble as a sender ;have to keep hi nibble of portc unchanged when sending lo nibble to lcd ;character comes to here in char movfw char movwf temp swapf temp,f ;move hi nibble to lo nibble movfw temp andlw b'00001111' ;make hi nibble all 0's, lo nibble is data movwf temp movfw lcd andlw b'11110000' ;make lo nibble all 0's, hi nibbel unchanged addwf temp,w movwf lcd BCF RW ; Set LCD to write BSF RS ; Set LCD to data mode BSF E ; toggle E for LCD BCF E movfw char movwf temp andlw b'00001111' ;make hi nibble all 0's, lo nibble is data movwf temp movfw lcd andlw b'11110000' ;make lo nibble all 0's, hi nibbel unchanged addwf temp,w movwf lcd nop BSF E ; toggle E for LCD BCF E RETURN ;============================================================ ;======================================================================= lcd_cmd ;character or command to be sent is in char ;======================================================================= call busy_check ; Wait for LCD to be ready movfw char movwf temp swapf temp,f ;move hi nibble to lo nibble movfw temp andlw b'00001111' ;make hi nibble all 0's, lo nibble is data movwf temp movfw lcd andlw b'11110000' ;make lo nibble all 0's, hi nibbel unchanged addwf temp,w movwf lcd BCF RW ; Set LCD to write BCF RS ; Set LCD to data mode BSF E ; toggle E for LCD BCF E movfw char movwf temp andlw b'00001111' ;make hi nibble all 0's, lo nibble is data movwf temp movfw lcd andlw b'11110000' ;make lo nibble all 0's, hi nibbel unchanged addwf temp,w movwf lcd nop BSF E ; toggle E for LCD BCF E RETURN ;============================================================================ ;=============================================================== busy_check ;=============================================================== ;WATCH!!! upper four bits of trisc should be same as in setup ;only change lower four bits bsf status, rp0 ; Bank 1 movlw b'11001111' ;make lcd bits inputs movwf trisc bcf status, rp0 ; Bank 0 bcf rs ; Set LCD for Command mode bsf rw ; Setup to read busy flag check2 bsf e ; Set E high bcf e ; Set E low movfw lcd ;copy lcd to w andlw b'00001111' ;clear hi nibble (data is in lower nibble) movwf temp ;copy to temp swapf temp,f ;swap lo to hi (hi now has data) bsf e ;toggle bcf e ;toggle movfw lcd ;copy lcd tpo w andlw b'00001111' ;clear hi nibble (data is in lower nibble) addwf temp,f ;add w to existing temp, and call it temp btfsc temp,7 ;skip if bit7 of temp is clear ;which is the busy flag goto check2 ;still busy bcf rw ;set lcd to write bsf status, rp0 ;Bank 1 movlw b'11000000' movwf trisc bcf status, rp0 ; Bank 0 nop ;these nops are need nop ;as LCD fucks about with addresses nop ;for 4 uS after the busy flag drops nop nop return ;======================================================================= part 4 154 bytes -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! 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