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 #include "ipmb.h"
   6
   7 #define TWCR_ACK TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC);
   8 #define TWCR_NACK TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC);
   9 #define TWCR_RESET TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(1<<TWSTO)|(0<<TWWC);
  10
  11 static volatile unsigned char databuf[12];
  12 static volatile uint8_t pos = 0x00;
  13
  14 void i2c_init()
  15 {
  16         TWAR = BMC_ADDR & 0xfe;
  17         TWDR = 0x00;
  18         TWCR &= ~((1<<TWSTA) | (1<<TWSTO));
  19         TWCR |= ((1<<TWEA) | (1<<TWEN) | (1<<TWIE));
  20         printf("Status: 0x%02x\n", TW_STATUS);
  21         PORTC = 0x03;
  22 }
  23
  24 void i2c_send(unsigned char *buf, int len)
  25 {
  26         uint8_t old_TWCR = TWCR;
  27         uint8_t old_SREG = SREG;
  28         int i;
  29
  30         cli();
  31
  32         TWCR = ((1<<TWINT) | (1<<TWSTA) | (1<<TWEN)); /* Send start */
  33
  34         while(!(TWCR & (1<<TWINT))) {}
  35         if ((TW_STATUS & 0xf8) != TW_START)
  36                 goto out;
  37
  38         TWDR = buf[0]; /* SLA_W */
  39         TWCR = ((1<<TWINT) | (1<<TWEN));
  40
  41         while(!(TWCR & (1<<TWINT))) {}
  42         if ((TW_STATUS & 0xf8) != TW_MT_SLA_ACK)
  43                 goto out;
  44
  45         for(i = 1; i < len; i++) {
  46                 TWDR = buf[i]; /* Send Data */
  47                 TWCR = ((1<<TWINT) | (1<<TWEN));
  48
  49                 while(!(TWCR & (1<<TWINT))) {}
  50                 if ((TW_STATUS & 0xf8) != TW_MT_DATA_ACK)
  51                         goto out;
  52         }
  53
  54         TWCR = ((1<<TWINT) | (1<<TWEN) | (1<<TWSTO));
  55
  56         printf("I2C Data sent 0x%02x\n", TW_STATUS);
  57
  58
  59 out:
  60         TWDR = 0x00;
  61         TWCR = old_TWCR;
  62         SREG = old_SREG;
  63 }
  64
  65 ISR (TWI_vect, ISR_BLOCK)
  66 {
  67         switch (TW_STATUS) {
  68                 case TW_SR_SLA_ACK:
  69 #ifdef DEBUG
  70                         printf("I2C: Slave 0x%02x adressed\n", TWDR);
  71 #endif
  72                         pos = 0x00;
  73                         databuf[pos] = TWDR;
  74                         pos++;
  75                         TWCR_ACK;
  76                         break;
  77
  78                 case TW_SR_DATA_ACK:
  79 #ifdef DEBUG
  80                         printf("I2C: Data received: 0x%02x\n", TWDR);
  81 #endif
  82                         databuf[pos] = TWDR;
  83                         pos++;
  84                         TWCR_ACK;
  85                         break;
  86
  87                 case TW_SR_STOP:
  88 #ifdef DEBUG
  89                         printf("I2C: STOP received\n");
  90 #endif
  91                         decode_ipmb_pkt((unsigned char*)databuf, pos);
  92                         pos = 0x00;
  93                         TWCR_RESET;
  94                         break;
  95
  96                 default:
  97                         printf("I2C: Unimplemented status 0x%02x\n", TW_STATUS);
  98                         TWCR_RESET;
  99                         break;
 100         }
 101 }