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1 | #include <util/twi.h> | |
2 | #include <avr/interrupt.h> | |
3 | #include <stdio.h> | |
4 | #include "i2c.h" | |
5 | #include "bmc.h" | |
6 | #include "ipmb.h" | |
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 | ||
12 | volatile unsigned char i2c_databuf[24]; | |
13 | volatile uint8_t i2c_len = 0x00; | |
14 | static volatile uint8_t i2c_pos = 0x00; | |
15 | volatile uint8_t i2c_done = 0x00; | |
16 | ||
17 | void i2c_init() | |
18 | { | |
19 | TWBR = 0xff; | |
20 | TWAR = BMC_ADDR & 0xfe; | |
21 | TWDR = 0x00; | |
22 | TWCR &= ~((1<<TWSTA) | (1<<TWSTO)); | |
23 | TWCR |= ((1<<TWEA) | (1<<TWEN) | (1<<TWIE)); | |
24 | #ifdef __AVR_ATmega16__ | |
25 | PORTC = 0x03; | |
26 | #else | |
27 | #error "Don't know how to set pullups for this chip, please add support" | |
28 | #endif | |
29 | } | |
30 | ||
31 | void 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 != TW_START) { | |
43 | #ifdef DEBUG | |
44 | printf("I2C: error sending START\n"); | |
45 | #endif | |
46 | goto out; | |
47 | } | |
48 | ||
49 | TWDR = buf[0]; /* SLA_W */ | |
50 | TWCR = ((1<<TWINT) | (1<<TWEN)); | |
51 | ||
52 | while(!(TWCR & (1<<TWINT))) {} | |
53 | if (TW_STATUS != TW_MT_SLA_ACK) { | |
54 | #ifdef DEBUG | |
55 | printf("I2C: error sending SLA_W\n"); | |
56 | #endif | |
57 | goto out2; | |
58 | } | |
59 | ||
60 | for(i = 1; i < len; i++) { | |
61 | TWDR = buf[i]; /* Send Data */ | |
62 | TWCR = ((1<<TWINT) | (1<<TWEN)); | |
63 | ||
64 | while(!(TWCR & (1<<TWINT))) {} | |
65 | if (TW_STATUS != TW_MT_DATA_ACK) { | |
66 | #ifdef DEBUG | |
67 | printf("I2C: error sending DATA byte %d\n", i); | |
68 | #endif | |
69 | goto out2; | |
70 | } | |
71 | } | |
72 | ||
73 | #ifdef DEBUG | |
74 | printf("I2C Data sent\n"); | |
75 | #endif | |
76 | ||
77 | out2: | |
78 | TWCR = ((1<<TWINT) | (1<<TWEN) | (1<<TWSTO)); | |
79 | while(TWCR & (1<<TWSTO)) {} | |
80 | ||
81 | out: | |
82 | SREG = old_SREG; | |
83 | TWCR = old_TWCR | (1<<TWINT); | |
84 | } | |
85 | ||
86 | ISR (TWI_vect, ISR_BLOCK) | |
87 | { | |
88 | if (i2c_done) | |
89 | TWCR_RESET; | |
90 | ||
91 | switch (TW_STATUS) { | |
92 | case TW_SR_SLA_ACK: | |
93 | #ifdef DEBUG | |
94 | printf("I2C: Slave 0x%02x adressed\n", TWDR); | |
95 | #endif | |
96 | i2c_pos = 0x00; | |
97 | i2c_databuf[i2c_pos] = TWDR; | |
98 | i2c_pos++; | |
99 | TWCR_ACK; | |
100 | break; | |
101 | ||
102 | case TW_SR_DATA_ACK: | |
103 | #ifdef DEBUG | |
104 | printf("I2C: Data received: 0x%02x\n", TWDR); | |
105 | #endif | |
106 | if (i2c_pos >= sizeof(i2c_databuf)) { | |
107 | TWCR_RESET; | |
108 | i2c_pos = 0x00; | |
109 | break; | |
110 | } | |
111 | i2c_databuf[i2c_pos] = TWDR; | |
112 | i2c_pos++; | |
113 | TWCR_ACK; | |
114 | break; | |
115 | ||
116 | case TW_SR_STOP: | |
117 | #ifdef DEBUG | |
118 | printf("I2C: STOP received\n"); | |
119 | #endif | |
120 | i2c_len = i2c_pos; | |
121 | i2c_pos = 0x00; | |
122 | i2c_done = 0x01; | |
123 | TWCR_RESET; | |
124 | break; | |
125 | ||
126 | case TW_NO_INFO: | |
127 | #ifdef DEBUG | |
128 | printf("I2C: TW_NO_INFO received status 0x%2x\n", TW_STATUS); | |
129 | #endif | |
130 | TWCR |= (1<<TWINT); | |
131 | break; | |
132 | ||
133 | default: | |
134 | #ifdef DEBUG | |
135 | printf("I2C: Unimplemented status 0x%02x\n", TW_STATUS); | |
136 | #endif | |
137 | TWCR_RESET; | |
138 | break; | |
139 | } | |
140 | } |