 NEW!  |
This is my first decent bit of code for the PICmicro. It's a display control library that was distributed to a few members of the PICList for testing. I have used the serial control library (lcd_ser.inc) extensively - LCDs make great debugging tools. Examine the examples carefully - almost all you need to know is contained in them.
A small bug in the 4-bit driver code was fixed on 26 May 2003. This bug meant that some display panels (such as the Optrex DMC16106C) would miss characters sent to the display.
LIST
; PIC16-series PAGE-switching macros
; By P. Pemberton, Jr.
; WWW: http://www.philpem.me.uk/
; Email: piclist@philpem.me.uk
; This software is distributed under the BSD License. You are free to do whatever
; you want with this code, but I would appreciate an email first. I would also
; appreciate copies of any modifications you make.
;
; Provides:
; BANK0 Switch to RAM BANK 0
; BANK1 Switch to RAM BANK 1
; BANK2 Switch to RAM BANK 2
; BANK3 Switch to RAM BANK 3
NOLIST
#ifndef __BANKS_INCLUDED
#define __BANKS_INCLUDED
BANK0 MACRO ; Macro to select data RAM BANK 0
BCF STATUS,RP0
BCF STATUS,RP1
ENDM
BANK1 MACRO ; Macro to select data RAM BANK 1
BSF STATUS,RP0
BCF STATUS,RP1
ENDM
BANK2 MACRO ; Macro to select data RAM BANK 2
BCF STATUS,RP0
BSF STATUS,RP1
ENDM
BANK3 MACRO ; Macro to select data RAM BANK 3
BSF STATUS,RP0
BSF STATUS,RP1
ENDM
#endif
LIST
; Universal PIC LCD Interface Module ; HD44780 main handler/common functions (LCD_CMN.INC) ; NOTE: DO NOT #INCLUDE THIS FILE - #INCLUDE ONE OF THE BACKENDS INSTEAD! ; By P. Pemberton, Jr. ; WWW: http://www.philpem.me.uk/ ; Email: piclist@philpem.me.uk ; This software is distributed under the BSD License. You are free to do whatever ; you want with this code, but I would appreciate an email first. I would also ; appreciate copies of any modifications you make. CBLOCK __LCD_DOCBUFF ; Display Control settings ENDC ; Initialize LCD LCD_INIT: MOVLW B'00000100' ; Init DOCBUFF MOVWF __LCD_DOCBUFF CALL __LCD_INIT ; Init the LCD RETURN ; Return ; Display Clear LCD_CLRSCR: MOVLW B'00000001' ; Clear the LCD display CALL LCD_SENDINS RETURN ; Display On/Off - If W=0 then display off else display on LCD_ONOFF: BSF __LCD_DOCBUFF, 2 ; Assume W != 0 IORLW 0 ; Update flags BTFSC STATUS, Z ; Zero? BCF __LCD_DOCBUFF, 2 ; W=0; turn off the display MOVF __LCD_DOCBUFF, W ; Move control byte into W IORLW .8 ; Set command bit CALL LCD_SENDINS ; Send the instruction RETURN ; Cursor On/Off - If W=0 then cursor off else cursor on LCD_CURSOR: BSF __LCD_DOCBUFF, 1 ; Assume W != 0 IORLW 0 ; Update flags BTFSC STATUS, Z ; Zero? BCF __LCD_DOCBUFF, 1 ; W=0; turn off the cursor MOVF __LCD_DOCBUFF, W ; Move control byte into W IORLW .8 ; Set command bit CALL LCD_SENDINS ; Send the instruction RETURN ; Blinking Cursor On/Off - If W=0 then blinking cursor on else off LCD_CURSBLINK: BSF __LCD_DOCBUFF, 0 ; Assume W != 0 IORLW 0 ; Update flags BTFSC STATUS, Z ; Zero? BCF __LCD_DOCBUFF, 0 ; W=0; turn off the block cursor MOVF __LCD_DOCBUFF, W ; Move control byte into W IORLW .8 ; Set command bit CALL LCD_SENDINS ; Send the instruction RETURN ; Move cursor - W=offset LCD_MOVECURS: IORLW B'10000000' ; Set command bit CALL LCD_SENDINS ; Send the instruction RETURN ; Move cursor to Line 1 LCD_LINE1: MOVLW 0x00 ; Move cursor to 0x00 CALL LCD_MOVECURS RETURN ; Move cursor to Line 2 LCD_LINE2: MOVLW 0x40 ; Move cursor to 0x40 CALL LCD_MOVECURS RETURN
; Universal PIC LCD Interface Module
; HD44780 4-bit mode transport layer/backend (LCD_4BIT.INC)
; By P. Pemberton, Jr.
; WWW: http://www.philpem.me.uk/
; Email: piclist@philpem.me.uk
; This software is distributed under the BSD License. You are free to do whatever
; you want with this code, but I would appreciate an email first. I would also
; appreciate copies of any modifications you make.
;
; Pindefs required:
; LCD_D7 The PIC pin connected to the LCD's D7 pin (ex: PORTB,3)
; LCD_D6 The PIC pin connected to the LCD's D6 pin (ex: PORTB,2)
; LCD_D5 The PIC pin connected to the LCD's D5 pin (ex: PORTB,1)
; LCD_D4 The PIC pin connected to the LCD's D4 pin (ex: PORTB,0)
; LCD_E The PIC pin connected to the LCD's E pin (ex: PORTB,5)
; LCD_RS The PIC pin connected to the LCD's RS pin (ex: PORTB,4)
CBLOCK
__LCD_TEMP0
__LCD_TEMP1
ENDC
; Send a byte to the LCD, assumes RS already set
__LCD_SEND:
MOVWF __LCD_TEMP0 ; Store byte in Temp 0
BCF LCD_D7 ; Clear data bits
BCF LCD_D6
BCF LCD_D5
BCF LCD_D4
BTFSC __LCD_TEMP0, 7 ; Load high nibble
BSF LCD_D7
BTFSC __LCD_TEMP0, 6
BSF LCD_D6
BTFSC __LCD_TEMP0, 5
BSF LCD_D5
BTFSC __LCD_TEMP0, 4
BSF LCD_D4
BSF LCD_E ; Strobe E
GOTO $+1
BCF LCD_E
BCF LCD_D7 ; Clear data bits
BCF LCD_D6
BCF LCD_D5
BCF LCD_D4
BTFSC __LCD_TEMP0, 3 ; Load low nibble
BSF LCD_D7
BTFSC __LCD_TEMP0, 2
BSF LCD_D6
BTFSC __LCD_TEMP0, 1
BSF LCD_D5
BTFSC __LCD_TEMP0, 0
BSF LCD_D4
BSF LCD_E ; Strobe E
GOTO $+1
BCF LCD_E
RETURN
; Send an instruction byte to the LCD
LCD_SENDINS:
BCF LCD_RS ; RS low=instruction
CALL __LCD_SEND ; Send the instruction byte
CALL __LCD_SHORTDELAY ; Short delay for instruction
RETURN
; Send a character to the LCD
LCD_PUTCH:
BSF LCD_RS ; RS high=character
CALL __LCD_SEND ; Send the character
CALL __LCD_SHORTDELAY ; Short delay for data
RETURN
; Initialize the LCD
__LCD_INIT:
CALL __LCD_LONGDELAY ; Long init delay
MOVLW B'00110011' ; 2x 8bit resets
CALL LCD_SENDINS
MOVLW B'00110011' ; 2x 8bit resets
CALL LCD_SENDINS
MOVLW B'00110010' ; 8bit reset then 4bit reset
CALL LCD_SENDINS
MOVLW B'00101100' ; Function Set - 4bit, 2 lines
CALL LCD_SENDINS
MOVLW B'00000110' ; Mode Set - incr. w/crsr shift
CALL LCD_SENDINS
MOVLW B'00001100' ; Display on, cursor & blink off
CALL LCD_SENDINS
MOVLW B'00000001' ; Display Clear
CALL LCD_SENDINS
MOVLW B'00000010' ; Cursor Home
CALL LCD_SENDINS
CALL __LCD_LONGDELAY ; Long post-init delay
RETURN
; Long delay for init
__LCD_LONGDELAY:
CLRF __LCD_TEMP0
__LCD_LONGDEL:
CLRF __LCD_TEMP1
__LCD_SHORTDEL:
DECFSZ __LCD_TEMP1, F
GOTO __LCD_SHORTDEL
DECFSZ __LCD_TEMP0, F
GOTO __LCD_LONGDEL
RETURN
; Short delay between commands
__LCD_SHORTDELAY:
MOVLW 0x14
MOVWF __LCD_TEMP1
__LCD_SHORTLOOP:
DECFSZ __LCD_TEMP1, F
GOTO __LCD_SHORTLOOP
RETURN
; Include the Common LCD Functions
INCLUDE "lcd_cmn.inc"
; Universal PIC LCD Interface Module
; HD44780 serial mode transport layer/backend (LCD_SER.INC)
; By P. Pemberton, Jr.
; WWW: http://www.philpem.me.uk/
; Email: piclist@philpem.me.uk
; This software is distributed under the BSD License. You are free to do whatever
; you want with this code, but I would appreciate an email first. I would also
; appreciate copies of any modifications you make.
;
; Pindefs required:
; LCD_DATA The PIC pin connected to the A and B pins on the
; 74LS164 (ex: PORTB,5)
; LCD_CLOCK The PIC pin connected to the LS164's CLOCK pin
; (ex: PORTB,4)
INCLUDE "banks.inc"
; File register Usage
CBLOCK
__LCD_DLAY ; Delay variable
__LCD_NOTEMP ; Temporary variable for nibble output
__LCD_TEMP ; Temporary variable
__LCD_CNTR ; Counter
ENDC
__LCD_INIT:
CALL __LCD_DLAY5 ; Wait 20 msecs before Reset
CALL __LCD_DLAY5
CALL __LCD_DLAY5
CALL __LCD_DLAY5
BCF STATUS, C ; RS=0 (instruction)
MOVLW 0x30 ; RESET
CALL __LCD_NIBBLE ; Send the nibble
CALL __LCD_DLAY5 ; Wait 5mS before resending
BSF LCD_DATA ; Send again.
BCF LCD_DATA
CALL __LCD_DLAY160 ; Wait 160uS before resending
BSF LCD_DATA
BCF LCD_DATA
CALL __LCD_DLAY160 ; Wait 160uS before sending
BCF STATUS, C ; RS=0 (instruction)
MOVLW 0x20 ; Set 4-bit (nibble) mode
CALL __LCD_NIBBLE ; Send the nibble
CALL __LCD_DLAY160 ; Wait 160uS before sending
MOVLW 0x28 ; Two line mode, 4-bit
CALL LCD_SENDINS
CALL __LCD_DLAY160
MOVLW 0x08 ; Turn off the display
CALL LCD_SENDINS
MOVLW 0x01 ; Clear the DDRAM
CALL LCD_SENDINS
CALL __LCD_DLAY5 ; Can take up to 5uS
MOVLW 0x06 ; Set cursor direction
CALL LCD_SENDINS
MOVLW 0x0C ; Display on
CALL LCD_SENDINS
CALL __LCD_DLAY160
RETURN
LCD_PUTCH: ; Send a character to the LCD
MOVWF __LCD_DLAY ; Temporary store.
BSF STATUS, C ; RS=1 (data)
CALL __LCD_NIBBLE ; Send the high nibble
SWAPF __LCD_DLAY, W ; Low nibble -> W
BSF STATUS, C ; RS=1 (data)
CALL __LCD_NIBBLE ; Send the low nibble
RETURN
LCD_SENDINS: ; Send an instruction to the LCD
MOVWF __LCD_DLAY ; Temporary store
BCF STATUS, C ; RS=0 (instruction)
CALL __LCD_NIBBLE ; Send the high nibble
SWAPF __LCD_DLAY, W ; Low nibble -> W
BCF STATUS, C ; RS=0 (instruction)
CALL __LCD_NIBBLE ; Send the low nibble
RETURN
__LCD_NIBBLE: ; Sends a nibble (4 bits) to the LCD
MOVWF __LCD_NOTEMP ; Temporarily store the nibble
RRF __LCD_NOTEMP, F ; Save the RS bit
BSF STATUS, C ; Carry high
RRF __LCD_NOTEMP, F ; Save the gate bit
MOVLW .0 ; Clear the shift register
CALL __LCD_SEND
MOVF __LCD_NOTEMP, W ; Send the nibble to the LCD
CALL __LCD_SEND
BSF LCD_DATA ; Clock in the data
BCF LCD_DATA
RETURN
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Send the byte in W to the 74HCT164
__LCD_SEND:
MOVWF __LCD_TEMP ; Store byte
MOVLW .8 ; Eight data bits
MOVWF __LCD_CNTR ; Store in counter
__LCD_SENDLOOP:
MOVLW 0
RLF __LCD_TEMP, F ; Rotate left into carry
BCF LCD_DATA ; Assume carry low
BTFSC STATUS, C ; Carry high?
BSF LCD_DATA ; Yes. Set port bit
; GOTO $+1 ; Wait for the data line to settle
BSF LCD_CLOCK ; Clock high
; GOTO $+1 ; Make sure the HC164 sees the transition
BCF LCD_CLOCK ; Clock low
DECFSZ __LCD_CNTR, F ; Decrement counter
GOTO __LCD_SENDLOOP ; Not zero yet; keep going
RETURN ; Counter=0; return.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
__LCD_DLAY160: ; 160uS delay
MOVLW .256-(160/4) ; Loop until carry set
ADDLW .1
BTFSS STATUS, C
GOTO $-2
RETURN
__LCD_DLAY5: ; 5mS delay
MOVLW .4 ; Set up the Delay
MOVWF __LCD_DLAY
MOVLW .256 - 0x0E8 ; Inner loop
ADDLW 1
BTFSC STATUS, Z
DECFSZ __LCD_DLAY, F ; Outer loop
GOTO $-3
RETURN
; Include the Common LCD Functions
INCLUDE "lcd_cmn.inc"
; Universal PIC LCD Interface Module ; 74LS164-to-LCD test program ; By P. Pemberton, Jr. ; WWW: http://www.philpem.me.uk/ ; Email: piclist@philpem.me.uk ; This software is distributed under the BSD License. You are free to do whatever ; you want with this code, but I would appreciate an email first. I would also ; appreciate copies of any modifications you make. ; ; Connections: ; PIC 74LS164 LCD ; RB7 1 and 2 via 10k resistor to "E" ; RB6 8 ; 5 D4 ; 6 D5 ; 10 D6 ; 11 D7 ; 12 RS ; 13 to 1N4148 cathode ; Vcc 9 and 14 Vcc ; Vss 7 Vss ; E to 1N4148 anode ; ; ; The contrast pin on the LCD should be connected as shown in the LCD module's ; datasheet. ; ; The above circuit is based on one included in an article written by ; Myke Predko for www.rentron.com ;; PIC setup and toplevel includes LIST P=16F874 INCLUDE <p16f874.inc> INCLUDE "banks.inc" ; Pindefs #DEFINE LCD_DATA PORTB, 7 #DEFINE LCD_CLOCK PORTB, 6 ; Variables CBLOCK 0x20 ENDC ; Reset vector ORG 0 GOTO START ; Interrupt vector ORG 4 GOTO START ; Start of code ORG 5 START: CLRF PORTB ; Clear PORTB PAGE1 ; Bank 1 BCF LCD_DATA ; Data, clock=outputs BCF LCD_CLOCK PAGE0 ; Bank 0 CALL LCD_INIT ; Init the LCD CLRF FSR ; Message loop MSGLOOP: MOVF FSR, W INCF FSR, F CALL MESSAGE IORLW .0 BTFSC STATUS, Z GOTO MSGDONE CALL LCD_PUTCH GOTO MSGLOOP MSGDONE: MOVLW .1 ; Block Cursor on CALL LCD_CURSBLINK CALL LCD_LINE2 MOVLW "2" CALL LCD_PUTCH MOVLW "0" CALL LCD_PUTCH MOVLW "." CALL LCD_PUTCH MOVLW "0" CALL LCD_PUTCH MOVLW 0x1A CALL LCD_PUTCH GOTO $ MESSAGE: ADDWF PCL, F DT "Hello.",0 ;; Final post-code includes INCLUDE "lcd_ser.inc" END
; Universal PIC LCD Interface Module ; 4-bit LCD test program ; By P. Pemberton, Jr. ; WWW: http://www.philpem.me.uk/ ; Email: piclist@philpem.me.uk ; This software is distributed under the BSD License. You are free to do whatever ; you want with this code, but I would appreciate an email first. I would also ; appreciate copies of any modifications you make. ; ; Connections: ; PIC LCD ; RB5 E ; RB4 RS ; RB3 D7 ; RB2 D6 ; RB1 D5 ; RB0 D4 ; ; The contrast pin on the LCD should be connected as shown in the LCD module's ; datasheet. ;; PIC setup and toplevel includes LIST P=16F874 INCLUDE <p16f874.inc> INCLUDE "banks.inc" ; Pindefs #DEFINE LCD_D7 PORTB, 3 #DEFINE LCD_D6 PORTB, 2 #DEFINE LCD_D5 PORTB, 1 #DEFINE LCD_D4 PORTB, 0 #DEFINE LCD_E PORTB, 5 #DEFINE LCD_RS PORTB, 4 ; Variables CBLOCK 0x20 ENDC ; Reset vector ORG 0 GOTO START ; Interrupt vector ORG 4 GOTO START ; Start of code ORG 5 START: CLRF PORTB ; Clear PORTB PAGE1 ; Bank 1 BCF LCD_D7 ; Databits=outputs BCF LCD_D6 BCF LCD_D5 BCF LCD_D4 BCF LCD_RS ; RS, E=outputs BCF LCD_E PAGE0 ; Bank 0 CALL LCD_INIT ; Init the LCD CLRF FSR ; Message loop MSGLOOP: MOVF FSR, W INCF FSR, F CALL MESSAGE IORLW .0 BTFSC STATUS, Z GOTO MSGDONE CALL LCD_PUTCH GOTO MSGLOOP MSGDONE: MOVLW .1 ; Blinking Cursor on CALL LCD_CURSBLINK CALL LCD_LINE2 MOVLW "2" CALL LCD_PUTCH MOVLW "0" CALL LCD_PUTCH MOVLW "." CALL LCD_PUTCH MOVLW "0" CALL LCD_PUTCH MOVLW 0x1A CALL LCD_PUTCH GOTO $ MESSAGE: ADDWF PCL, F DT "Hello.",0 ;; Final post-code includes INCLUDE "lcd_4bit.inc" END
Comments:
| file: /Techref/io/lcd/unilcd.htm, 16KB, , updated: 2009/10/1 09:34, local time: 2024/11/26 00:39,
owner: PAP-NA-554,
3.139.235.177:LOG IN
|
| ©2024 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions? <A HREF="http://techref.massmind.org/Techref/io/lcd/unilcd.htm"> Universal HD44780 LCD display driver library</A> |
| Did you find what you needed? |
Welcome to massmind.org! |
Welcome to techref.massmind.org! |
.