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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"
67a9a9e8 6#include "config.h"
d5193055 7#include "ipmb.h"
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8
9#define TWCR_ACK TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC);
10#define TWCR_NACK TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC);
11#define TWCR_RESET TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(1<<TWSTO)|(0<<TWWC);
12
45320371 13volatile unsigned char i2c_databuf[24];
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14volatile uint8_t i2c_len = 0x00;
15static volatile uint8_t i2c_pos = 0x00;
16volatile uint8_t i2c_done = 0x00;
77ad1a84 17
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18#define I2C_FREQ 20000UL
19
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20void i2c_init()
21{
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22 /* SCLf = F_CPU / (16 + 2 * TWBR * 4^TWPS)
23 * TWPS is 0 =>
24 * TWBR = (F_CPU/(2 * SCL)) - 8
25 */
26 TWBR = (F_CPU/(2*I2C_FREQ))-8;
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27 TWAR = BMC_ADDR & 0xfe;
28 TWDR = 0x00;
29 TWCR &= ~((1<<TWSTA) | (1<<TWSTO));
30 TWCR |= ((1<<TWEA) | (1<<TWEN) | (1<<TWIE));
e641fce6 31#ifdef __AVR_ATmega16__
7f52e040 32 PORTC = 0x03;
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33#else
34#error "Don't know how to set pullups for this chip, please add support"
35#endif
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36}
37
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38void i2c_send(unsigned char *buf, int len)
39{
40 uint8_t old_TWCR = TWCR;
41 uint8_t old_SREG = SREG;
42 int i;
43
44 cli();
45
46 TWCR = ((1<<TWINT) | (1<<TWSTA) | (1<<TWEN)); /* Send start */
47
48 while(!(TWCR & (1<<TWINT))) {}
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49 if (TW_STATUS != TW_START) {
50#ifdef DEBUG
51 printf("I2C: error sending START\n");
52#endif
d5193055 53 goto out;
87f4338b 54 }
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55
56 TWDR = buf[0]; /* SLA_W */
57 TWCR = ((1<<TWINT) | (1<<TWEN));
58
59 while(!(TWCR & (1<<TWINT))) {}
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60 if (TW_STATUS != TW_MT_SLA_ACK) {
61#ifdef DEBUG
62 printf("I2C: error sending SLA_W\n");
63#endif
64 goto out2;
65 }
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66
67 for(i = 1; i < len; i++) {
68 TWDR = buf[i]; /* Send Data */
69 TWCR = ((1<<TWINT) | (1<<TWEN));
70
71 while(!(TWCR & (1<<TWINT))) {}
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72 if (TW_STATUS != TW_MT_DATA_ACK) {
73#ifdef DEBUG
74 printf("I2C: error sending DATA byte %d\n", i);
75#endif
76 goto out2;
77 }
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78 }
79
27f7ea19 80#ifdef DEBUG
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81 printf("I2C Data sent\n");
82#endif
d5193055 83
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84out2:
85 TWCR = ((1<<TWINT) | (1<<TWEN) | (1<<TWSTO));
86 while(TWCR & (1<<TWSTO)) {}
87
d5193055 88out:
d5193055 89 SREG = old_SREG;
285b23e4 90 TWCR = old_TWCR | (1<<TWINT);
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91}
92
7f52e040 93ISR (TWI_vect, ISR_BLOCK)
99e4226b 94{
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95 if (i2c_done)
96 TWCR_RESET;
97
87f4338b 98 switch (TW_STATUS) {
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99 case TW_SR_SLA_ACK:
100#ifdef DEBUG
101 printf("I2C: Slave 0x%02x adressed\n", TWDR);
102#endif
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103 i2c_pos = 0x00;
104 i2c_databuf[i2c_pos] = TWDR;
105 i2c_pos++;
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106 TWCR_ACK;
107 break;
108
109 case TW_SR_DATA_ACK:
110#ifdef DEBUG
111 printf("I2C: Data received: 0x%02x\n", TWDR);
112#endif
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113 if (i2c_pos >= sizeof(i2c_databuf)) {
114 TWCR_RESET;
115 i2c_pos = 0x00;
116 break;
117 }
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118 i2c_databuf[i2c_pos] = TWDR;
119 i2c_pos++;
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120 TWCR_ACK;
121 break;
122
123 case TW_SR_STOP:
124#ifdef DEBUG
125 printf("I2C: STOP received\n");
126#endif
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127 i2c_len = i2c_pos;
128 i2c_pos = 0x00;
129 i2c_done = 0x01;
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130 TWCR_RESET;
131 break;
132
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133 case TW_NO_INFO:
134#ifdef DEBUG
135 printf("I2C: TW_NO_INFO received status 0x%2x\n", TW_STATUS);
136#endif
137 TWCR |= (1<<TWINT);
138 break;
139
77ad1a84 140 default:
f9d5c6e0 141#ifdef DEBUG
87f4338b 142 printf("I2C: Unimplemented status 0x%02x\n", TW_STATUS);
f9d5c6e0 143#endif
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144 TWCR_RESET;
145 break;
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146 }
147}
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