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interface between two PIC's using I2C

 
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qpnikepor
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interface between two PIC's using I2C
PostPosted: Mon Jan 11, 2010 10:28 pm     Reply with quote

Hi
I am trying to implement a simple network where the master sends two bytes indicating what characters to display.
The slave receives them and displays them.
Slave
Code:

#include<16f886.h>
#include<def_16f886.h>
#use delay(clock = 4000000)
#include<flex_lcd.h>
#fuses intrc_io, noprotect, nowdt
#use i2c(slave, sda = pin_c4, scl = pin_c3, address = 0xa0, fast, force_hw)

int8 address = 0xa0;
int8 buffer[5] = {0, 0, 0, 0, 0};
int8 buffer1;
int8 incoming = 0;
int8 first_byte = 0;
int8 second_byte = 0;
int8 state; 

#int_ssp
void ssp_interupt ()
{   
   state = i2c_isr_state();

   if(state < 0x80){         //Master is sending the data
         if(state==1) first_byte = i2c_read();
           if(state==2) second_byte = i2c_read();
   }
   if(state == 0x80)                     //Master is requesting data
   {
      i2c_write(buffer[address]);
   }
   
}

void main(void){
   lcd_init();
   lcd_send_byte(0,ALL_CLEAR);
   delay_ms(20);
   enable_interrupts(int_ssp);
   enable_interrupts(global);
   while(1){
      lcd_gotoxy(1,1);
    lcd_putc(first_byte);
   lcd_gotoxy(1,2);
   lcd_putc(second_byte);
   }
}



Master
Code:

#include<18F2510.h>
#include<def_18f2510.h>
#fuses intrc_io, NOBROWNOUT

#use delay(clock = 4000000)

#use i2c(master, SCL = pin_a4, SDA = pin_a5, fast)

void main(void){
   while(1){
   delay_ms(1);
   i2c_start();
   i2c_write(0xa0);
   i2c_write('S');
   i2c_write('B');
   i2c_stop();
   delay_ms(1000);
   }
}

I looked at all of the posts here about I2C slave and came up with code above. However, it doesn't seem to be working.
Anyone with idea?
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Mon Jan 11, 2010 11:10 pm     Reply with quote

Quote:
#int_ssp
void ssp_interupt ()
{
state = i2c_isr_state();

if(state < 0x80){ //Master is sending the data
if(state==1) first_byte = i2c_read();
if(state==2) second_byte = i2c_read();
}
if(state == 0x80) //Master is requesting data
{
i2c_write(buffer[address]);
}

}

Look at the way CCS does this routine in Ex_Slave.c. Try to follow their
style more closely. See what happens. Here's the file location:
Quote:
c:\Program Files\picc\Examples\Ex_Slave.c
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