git.zerfleddert.de Git - rsbs2/blob - bmc/i2c.c

   1 #include <util/twi.h>
   2 #include <avr/interrupt.h>
   3 #include <stdio.h>
   4 #include "i2c.h"
   5
   6 #define TWCR_ACK TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC);
   7 #define TWCR_NACK TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC);
   8 #define TWCR_RESET TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(1<<TWSTO)|(0<<TWWC);
   9
  10 void i2c_init()
  11 {
  12         TWAR = BMC_ADDR & 0xfe;
  13         TWDR = 0x00;
  14         TWCR &= ~((1<<TWSTA) | (1<<TWSTO));
  15         TWCR |= ((1<<TWEA) | (1<<TWEN) | (1<<TWIE));
  16         printf("Status: 0x%02x\n", TW_STATUS);
  17         PORTC = 0x03;
  18 }
  19
  20 ISR (TWI_vect, ISR_BLOCK)
  21 {
  22         printf("Interrupt, Status: 0x%02x, Data: 0x%02x!\n", TW_STATUS, TWDR);
  23
  24         switch (TW_STATUS) {
  25                 default:
  26                         TWCR_ACK;
  27                         break;
  28         }
  29 }