I2C Slave with a PIC

[tacbanon]

Hi again,
Here is the code I'm using..
Master pic using Pic16F877A

'-------------------------------------------------------------------------------
' Master
'-------------------------------------------------------------------------------
'-------------------------------------------------------------------------------


DEFINE OSC 4


'OPTION_REG.7 = 0


ADCON1 = 7


'------------------------------------------------------------------------------


DEFINE I2C_SLOW 1


TRISB.5 = 1
TRISB.7 = 1


'------------------------------------------------------------------------------


scl VAR PORTB.5        ' i2c clock input
sda VAR PORTB.7     ' i2c data input


'------------------------------------------------------------------------------


I2Caddress VAR BYTE


valor VAR BYTE


'------------------------------------------------------------------------------


' Set LCD Data port
DEFINE LCD_DREG PORTD
' Set starting Data BIT (0 OR 4) IF 4-BIT bus
DEFINE LCD_DBIT 4
' Set LCD Register Select port
DEFINE LCD_RSREG PORTC
' Set LCD Register Select BIT
DEFINE LCD_RSBIT 6
' Set LCD Enable port
DEFINE LCD_EREG PORTC
' Set LCD Enable BIT
DEFINE LCD_EBIT 7
' 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


'------------------------------------------------------------------------------


Pause 500       ' Wait for LCD to startup
LCDOut $fe, 1
LCDOut $fe, "Daniel"
Pause 500       ' Wait for LCD to startup


valor = 0


'------------------------------------------------------------------------------


main:
      I2Caddress = $3


      LCDOut $fe, 1
      LCDOut "Write 1 - LED ON"
      Pause 500


      I2CWrite SDA, SCL, I2Caddress, [6], bogus ' Write offset to slave
      Pause 500


      LCDOut $fe, 1
      LCDOut "Write 1 - LED OFF"
      Pause 500


      I2CWrite SDA, SCL, I2Caddress, [8], bogus ' Write to slave
      Pause 500


      LCDOut $fe, 1
      LCDOut "Reading 1..."
      Pause 500


      I2CRead SDA, SCL, I2Caddress, [valor], bogus ' Read from slave
      LCDOut $fe, 1
      LCDOut "Value1: ", DEC valor
      Pause 500


      '--------


      I2Caddress = $5


      LCDOut $fe, 1
      LCDOut "Write 2 - LED ON"
      Pause 500


      I2CWrite SDA, SCL, I2Caddress, [4], bogus ' Write to slave
      Pause 500


      LCDOut $fe, 1
      LCDOut "Write 2 - LED OFF"
      Pause 500


      I2CWrite SDA, SCL, I2Caddress, [10], bogus ' Write to slave
      Pause 500


      LCDOut $fe, 1
      LCDOut "Reading 2..."
      Pause 500


      I2CRead SDA, SCL, I2Caddress, [valor], bogus ' Read from slave
      LCDOut $fe, 1
      LCDOut "Value2: ", DEC valor
      Pause 500


      '--------


      GoTo main       ' Do it forever


'-------------------------------------------------------------------------------


bogus:
        LCDOut $fe,1, "Time out"    ' I2C command timed out
        Pause 500


        GoTo main


'-------------------------------------------------------------------------------


End

Here is the code for the Slave Pic16F88

DEFINE OSC 8
OSCCON = 110001 '8mhz


'------------------------------------------------------------------------------


CMCON = 7
ADCON1 = 0 ' Disable A/D converter
ADCON0 = 0
ANSEL = 0 ' all analog pins to digital


'--- tris port config here (don't use SCL & SDA pins other than I2C) ----------


DEFINE I2C_HOLD 1


TRISB.1 = 1
TRISB.4 = 1

'--- Alias pins ---------------------------------------------------------------


SDADIR VAR TRISB.1
SCLDIR VAR TRISB.4


'--- Define here your variables and alias -------------------------------------


LEDT VAR PORTA.2
LEDL VAR PORTB.7
LEDM VAR PORTB.6
LEDR VAR PORTB.5
readcnt VAR BYTE
datain VAR BYTE
WrData VAR BYTE


'--- Define used register flags ------------------------------------------------


SSPIF               VAR PIR1.3    ' SSP (I2C) interrupt flag
SSPIE               VAR PIE1.3 
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 SSPCON.4  ' SSP (I2C) SCK Release Control
SSPEN               VAR SSPCON.5  ' SSP (I2C) Enable
SSPOV               VAR SSPCON.6  ' SSP (I2C) Receive Overflow Indicator
WCOL                VAR SSPCON.7  ' SSP (I2C) Write Collision Detect
STAT_BF             VAR SSPSTAT.0 ' SSP (I2C) Buffer Full
STAT_RW             VAR SSPSTAT.2 ' SSP (I2C) Read/Write
STAT_DA             VAR SSPSTAT.5 ' SSP (I2C) Data/Address
CKE                 VAR SSPSTAT.6 ' SSP (I2C) Data/Address


'--- Rx Buffer defintion ------------------------------------------------------


RxBufferLEN         CON 1       
RxBuffer            VAR BYTE[Rxbufferlen]
RxBufferIndex       VAR BYTE


'--- Tx Buffer defintion ------------------------------------------------------


TxBufferLEN         CON 1
TxBuffer            VAR BYTE[txbufferlen]
TxBufferIndex       VAR BYTE


'--- Define constants ---------------------------------------------------------


I2Caddress          CON $3 ' Make address = 3


'--- Initialize I2C slave mode ------------------------------------------------


SCLDIR = 1          ' SCL must be an input before enabling interrupts
SDADIR = 1   
SSPADD = I2Caddress ' Set our address
SSPCON = $36        ' Set to I2C slave with 7-bit address
SSPSTAT = 0
SSPIE = 1 
SSPIF = 0 
RxBufferIndex = 0
TxBufferIndex = 0


'--- Initialization Done! -----------------------------------------------------


GoTo main


'--- I2C subroutine  ----------------------------------------------------------


i2cslave:                                      ' I2C slave subroutine
          SSPIF = 0                            ' Clear interrupt flag
          IF R_W = 1 Then i2crd                ' Read data from us
          IF BF = 0 Then i2cexit               ' Nothing in buffer so exit
          IF D_A = 1 Then i2cwr                ' Data for us (not address)
          IF SSPBUF != I2Caddress Then i2cexit ' Clear the address from the buffer
          readcnt = 0                          ' Mark as first read
          GoTo i2cexit


i2cwr:                                ' I2C write data to us
       datain = SSPBUF                ' Put buffer data into array
       Rxbuffer[Rxbufferindex]=datain
       Rxbufferindex=rxbufferindex+1


       IF rxbufferindex=RxBufferLEN Then           ' end of buffer transfer 
          WrData=1
          rxbufferindex=0
       EndIF


       GoTo i2cexit


i2crd:                                      ' I2C read data from us
       IF D_A = 0 Then
          TxBufferIndex = 0
       EndIF


       While STAT_BF : Wend                        ' loop while buffer is full


       wcol = 0                                    ' clear collision flag
       SSPBUF = TxBuffer[TxBufferIndex]


       While wcol 
             wcol = 0
             SSPBUF = TxBuffer[TxBufferIndex]
       Wend


       CKP = 1                                     ' release clock, allowing read by master
       TxBufferIndex = TxBufferIndex + 1           ' increment index
       IF TxBufferIndex = TxBufferlen Then         ' all bytes have been tx
          TxBufferIndex = 0                           ' reset index            
       EndIF
             
i2cexit:
         Return


'--- End I2C subroutine  ------------------------------------------------------


Main:
     
      pause 100
      txbuffer = 12


      IF SSPIF = 1 Then
         GoSub i2cslave
      EndIF


      SSPOV = 0
      WCOL = 0


      Select Case RxBuffer[0]
             Case 6
                     High LEDT
             Case 8
                     Low LEDT
      End Select


      WrData=0  
      GoTo Main


'------------------------------------------------------------------------------


End

The codes I'm using is from Daniel(copy and paste).
BTW I'm using a simulator...

regards,
tacbanon