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[rsbs2] / bmc / i2c.c
1 #include <util/twi.h>
2 #include <avr/interrupt.h>
3 #include <stdio.h>
4 #include "i2c.h"
5 #include "bmc.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 ISR (TWI_vect, ISR_BLOCK)
25 {
26 switch (TW_STATUS) {
27 case TW_SR_SLA_ACK:
28 #ifdef DEBUG
29 printf("I2C: Slave 0x%02x adressed\n", TWDR);
30 #endif
31 pos = 0x00;
32 databuf[pos] = TWDR;
33 pos++;
34 TWCR_ACK;
35 break;
36
37 case TW_SR_DATA_ACK:
38 #ifdef DEBUG
39 printf("I2C: Data received: 0x%02x\n", TWDR);
40 #endif
41 databuf[pos] = TWDR;
42 pos++;
43 TWCR_ACK;
44 break;
45
46 case TW_SR_STOP:
47 #ifdef DEBUG
48 printf("I2C: STOP received\n");
49 #endif
50 decode_bmc_cmd((unsigned char*)databuf, pos);
51 pos = 0x00;
52 TWCR_RESET;
53 break;
54
55 default:
56 printf("I2C: Unimplemented status 0x%02x\n", TW_STATUS);
57 TWCR_RESET;
58 break;
59 }
60 }
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