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use CTC unit to generate correct timings for power/reset
[rsbs2] / bmc / i2c.c
CommitLineData
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1#include <util/twi.h>
2#include <avr/interrupt.h>
3#include <stdio.h>
4#include "i2c.h"
da7751cb 5#include "bmc.h"
d5193055 6#include "ipmb.h"
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7
8#define TWCR_ACK TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC);
9#define TWCR_NACK TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC);
10#define TWCR_RESET TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(1<<TWSTO)|(0<<TWWC);
11
45320371 12volatile unsigned char i2c_databuf[24];
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13volatile uint8_t i2c_len = 0x00;
14static volatile uint8_t i2c_pos = 0x00;
15volatile uint8_t i2c_done = 0x00;
77ad1a84 16
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17void i2c_init()
18{
da7751cb 19 TWBR = 0xff;
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20 TWAR = BMC_ADDR & 0xfe;
21 TWDR = 0x00;
22 TWCR &= ~((1<<TWSTA) | (1<<TWSTO));
23 TWCR |= ((1<<TWEA) | (1<<TWEN) | (1<<TWIE));
e641fce6 24#ifdef __AVR_ATmega16__
7f52e040 25 PORTC = 0x03;
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26#else
27#error "Don't know how to set pullups for this chip, please add support"
28#endif
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29}
30
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31void i2c_send(unsigned char *buf, int len)
32{
33 uint8_t old_TWCR = TWCR;
34 uint8_t old_SREG = SREG;
35 int i;
36
37 cli();
38
39 TWCR = ((1<<TWINT) | (1<<TWSTA) | (1<<TWEN)); /* Send start */
40
41 while(!(TWCR & (1<<TWINT))) {}
42 if ((TW_STATUS & 0xf8) != TW_START)
43 goto out;
44
45 TWDR = buf[0]; /* SLA_W */
46 TWCR = ((1<<TWINT) | (1<<TWEN));
47
48 while(!(TWCR & (1<<TWINT))) {}
49 if ((TW_STATUS & 0xf8) != TW_MT_SLA_ACK)
50 goto out;
51
52 for(i = 1; i < len; i++) {
53 TWDR = buf[i]; /* Send Data */
54 TWCR = ((1<<TWINT) | (1<<TWEN));
55
56 while(!(TWCR & (1<<TWINT))) {}
57 if ((TW_STATUS & 0xf8) != TW_MT_DATA_ACK)
58 goto out;
59 }
60
61 TWCR = ((1<<TWINT) | (1<<TWEN) | (1<<TWSTO));
27f7ea19 62 while(TWCR & (1<<TWSTO)) {}
d5193055 63
27f7ea19 64#ifdef DEBUG
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65 printf("I2C Data sent\n");
66#endif
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67
68out:
69 TWDR = 0x00;
70 TWCR = old_TWCR;
71 SREG = old_SREG;
72}
73
7f52e040 74ISR (TWI_vect, ISR_BLOCK)
99e4226b 75{
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76 if (i2c_done)
77 TWCR_RESET;
78
75a01977 79 switch (TW_STATUS & 0xf8) {
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80 case TW_SR_SLA_ACK:
81#ifdef DEBUG
82 printf("I2C: Slave 0x%02x adressed\n", TWDR);
83#endif
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84 i2c_pos = 0x00;
85 i2c_databuf[i2c_pos] = TWDR;
86 i2c_pos++;
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87 TWCR_ACK;
88 break;
89
90 case TW_SR_DATA_ACK:
91#ifdef DEBUG
92 printf("I2C: Data received: 0x%02x\n", TWDR);
93#endif
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94 if (i2c_pos >= sizeof(i2c_databuf)) {
95 TWCR_RESET;
96 i2c_pos = 0x00;
97 break;
98 }
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99 i2c_databuf[i2c_pos] = TWDR;
100 i2c_pos++;
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101 TWCR_ACK;
102 break;
103
104 case TW_SR_STOP:
105#ifdef DEBUG
106 printf("I2C: STOP received\n");
107#endif
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108 i2c_len = i2c_pos;
109 i2c_pos = 0x00;
110 i2c_done = 0x01;
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111 TWCR_RESET;
112 break;
113
77ad1a84 114 default:
f9d5c6e0 115#ifdef DEBUG
75a01977 116 printf("I2C: Unimplemented status 0x%02x\n", (TW_STATUS & 0xf8));
f9d5c6e0 117#endif
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118 TWCR_RESET;
119 break;
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120 }
121}
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