Here is a little program that drives a LCD as a I2C slave
I think I found this on this forum.Code:* '* Version : 1.0 * '* Notes : PIC 18F4550 * '* : * '**************************************************************** define LOADER_USED 1 define RESET_ORG 800h define INTERRUPT_ORG 808h DEFINE OSC 48 '**** LCD ******************************************************* 'Set LCD Data port DEFINE LCD_DREG PORTA 'Set starting Data bit (0 or 4) if 4-bit bus DEFINE LCD_DBIT 0 'Set LCD Register Select port DEFINE LCD_RSREG PORTA 'Set LCD Register Select bit DEFINE LCD_RSBIT 4 'Set LCD Enable port DEFINE LCD_EREG PORTA 'Set LCD Enable bit DEFINE LCD_EBIT 5 'LCD RW Register PORT 'DEFINE LCD_RWREG PORTB 'LCD read/write pin bit 'DEFINE LCD_RWBIT 5 'Set LCD bus size (4 or 8 bits) DEFINE LCD_BITS 4 'Set number of lines on LCD DEFINE LCD_LINES 2 'Set command delay time in us DEFINE LCD_COMMANDUS 2000 'Set data delay time in us DEFINE LCD_DATAUS 50 ' Initialize ports and directions ADCON1 = $F 'port A digital CMCON = 7 'PortA Digital ' PicBasic Pro I2C slave program ' Alias pins scl VAR PORTB.1 ' I2C clock input sda VAR PORTB.0 ' I2C data input ' Define used register flags SSPIF VAR PIR1.3 ' SSP (I2C) interrupt flag BF VAR SSPSTAT.0 ' SSP (I2C) Buffer Full R_W VAR SSPSTAT.2 ' SSP (I2C) Read/Write D_A VAR SSPSTAT.5 ' SSP (I2C) Data/Address CKP VAR SSPCON1.4 ' SSP (I2C) SCK Release Control SSPEN VAR SSPCON1.5 ' SSP (I2C) Enable SSPOV VAR SSPCON1.6 ' SSP (I2C) Receive Overflow Indicator WCOL VAR SSPCON1.7 ' SSP (I2C) Write Collision Detect ' Define constants I2Caddress CON $A2 ' Make our address 2 ' Allocate RAM result VAR BYTE ' ADC result datain VAR BYTE ' Data in dataout VAR BYTE[8] ' Data out array readcnt VAR BYTE ' I2C read count readcnt = 0 ' Zero counter pause 500 lcdout $FE,1," I2C LCD" lcdout $FE,$C0," Ready" trisb = %00000000 portb.0 = 0 portb.1 = 0 TRISB = %11111111 'pause 500 ' Initialize I2C slave mode SSPADD = I2Caddress ' Set our address SSPCON2 = $0 ' General call address disabled SSPCON1 = $36 ' Set to I2C slave with 7-bit address GoTo mainloop ' Skip over subroutines i2cslave: ' I2C slave subroutine SSPIF = 0 ' Clear interrupt flag IF R_W = 1 Then goto i2crd ' Read data from us IF BF = 0 Then goto i2cexit ' Nothing in buffer so exit IF D_A = 1 Then goto i2cwr ' Data for us (not address) IF SSPBUF != I2Caddress Then goto i2cexit ' Clear the address from the buffer readcnt = 0 ' Mark as first read GoTo i2cexit i2cwr: ' I2C write data to us datain = SSPBUF ' Put data into array lcdout datain GoTo i2cexit i2crd: ' I2C read data from us IF D_A = 0 Then readcnt = 0 ' Mark as first read EndIF SSPBUF = dataout[readcnt] ' Get data from array CKP = 1 ' Release SCL line readcnt = readcnt + 1 ' Move along read count GoTo i2cexit ' That's it i2cexit: Return mainloop: ' Main program loop IF SSPIF = 1 Then ' Check for I2C interrupt flag GoSub i2cslave EndIF GoTo mainloop ' Do it all forever
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