1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
|
/*
ChibiOS - Copyright (C) 2006..2015 Giovanni Di Sirio
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
/**
* @file AVR/i2c_lld.c
* @brief AVR I2C subsystem low level driver source.
*
* @addtogroup I2C
* @{
*/
#include "hal.h"
#if HAL_USE_I2C || defined(__DOXYGEN__)
/*===========================================================================*/
/* Driver local definitions. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver exported variables. */
/*===========================================================================*/
/** @brief I2C driver identifier.*/
#if AVR_I2C_USE_I2C1 || defined(__DOXYGEN__)
I2CDriver I2CD1;
#endif
/*===========================================================================*/
/* Driver local variables and types. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver local functions. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver interrupt handlers. */
/*===========================================================================*/
#if AVR_I2C_USE_I2C1 || defined(__DOXYGEN__)
/**
* @brief I2C event interrupt handler.
*
* @notapi
*/
OSAL_IRQ_HANDLER(TWI_vect) {
OSAL_IRQ_PROLOGUE();
I2CDriver *i2cp = &I2CD1;
switch (TWSR & 0xF8) {
case TWI_START:
case TWI_REPEAT_START:
TWDR = (i2cp->addr << 1);
if ((i2cp->txbuf == NULL) || (i2cp->txbytes == 0) || (i2cp->txidx == i2cp->txbytes)) {
TWDR |= 0x01;
}
TWCR = ((1 << TWINT) | (1 << TWEN) | (1 << TWIE));
break;
case TWI_MASTER_TX_ADDR_ACK:
case TWI_MASTER_TX_DATA_ACK:
if (i2cp->txidx < i2cp->txbytes) {
TWDR = i2cp->txbuf[i2cp->txidx++];
TWCR = ((1 << TWINT) | (1 << TWEN) | (1 << TWIE));
} else {
if (i2cp->rxbuf && i2cp->rxbytes) {
TWCR = ((1 << TWSTA) | (1 << TWINT) | (1 << TWEN) | (1 << TWIE));
} else {
TWCR = ((1 << TWSTO) | (1 << TWINT) | (1 << TWEN));
_i2c_wakeup_isr(i2cp);
}
}
break;
case TWI_MASTER_RX_ADDR_ACK:
if (i2cp->rxidx == (i2cp->rxbytes - 1)) {
TWCR = ((1 << TWINT) | (1 << TWEN) | (1 << TWIE));
} else {
TWCR = ((1 << TWEA) | (1 << TWINT) | (1 << TWEN) | (1 << TWIE));
}
break;
case TWI_MASTER_RX_DATA_ACK:
i2cp->rxbuf[i2cp->rxidx++] = TWDR;
if (i2cp->rxidx == (i2cp->rxbytes - 1)) {
TWCR = ((1 << TWINT) | (1 << TWEN) | (1 << TWIE));
} else {
TWCR = ((1 << TWEA) | (1 << TWINT) | (1 << TWEN) | (1 << TWIE));
}
break;
case TWI_MASTER_RX_DATA_NACK:
i2cp->rxbuf[i2cp->rxidx] = TWDR;
TWCR = ((1 << TWSTO) | (1 << TWINT) | (1 << TWEN));
_i2c_wakeup_isr(i2cp);
case TWI_MASTER_TX_ADDR_NACK:
case TWI_MASTER_TX_DATA_NACK:
case TWI_MASTER_RX_ADDR_NACK:
i2cp->errors |= I2C_ACK_FAILURE;
break;
case TWI_ARBITRATION_LOST:
i2cp->errors |= I2C_ARBITRATION_LOST;
break;
case TWI_BUS_ERROR:
i2cp->errors |= I2C_BUS_ERROR;
break;
default:
/* FIXME: only gets here if there are other MASTERs in the bus */
TWCR = ((1 << TWSTO) | (1 << TWINT) | (1 << TWEN));
_i2c_wakeup_error_isr(i2cp);
}
if (i2cp->errors != I2C_NO_ERROR) {
TWCR = ((1 << TWSTO) | (1 << TWINT) | (1 << TWEN));
_i2c_wakeup_error_isr(i2cp);
}
OSAL_IRQ_EPILOGUE();
}
#endif /* AVR_I2C_USE_I2C1 */
/*===========================================================================*/
/* Driver exported functions. */
/*===========================================================================*/
/**
* @brief Low level I2C driver initialization.
*
* @notapi
*/
void i2c_lld_init(void) {
i2cObjectInit(&I2CD1);
I2CD1.thread = NULL;
}
/**
* @brief Configures and activates the I2C peripheral.
*
* @param[in] i2cp pointer to the @p I2CDriver object
*
* @notapi
*/
void i2c_lld_start(I2CDriver *i2cp) {
uint32_t clock_speed = 100000;
/* TODO: Test TWI without external pull-ups (use internal) */
/* Configure prescaler to 1 */
TWSR &= 0xF8;
if (i2cp->config != NULL)
clock_speed = i2cp->config->clock_speed;
/* Configure baudrate */
TWBR = ((F_CPU / clock_speed) - 16) / 2;
}
/**
* @brief Deactivates the I2C peripheral.
*
* @param[in] i2cp pointer to the @p I2CDriver object
*
* @notapi
*/
void i2c_lld_stop(I2CDriver *i2cp) {
if (i2cp->state != I2C_STOP) {
/* Disable TWI subsystem and stop all operations */
TWCR &= ~(1 << TWEN);
}
}
/**
* @brief Receives data via the I2C bus as master.
*
* @param[in] i2cp pointer to the @p I2CDriver object
* @param[in] addr slave device address
* @param[out] rxbuf pointer to the receive buffer
* @param[in] rxbytes number of bytes to be received
* @param[in] timeout the number of ticks before the operation timeouts,
* the following special values are allowed:
* - @a TIME_INFINITE no timeout.
* .
* @return The operation status.
* @retval MSG_OK if the function succeeded.
* @retval MSG_RESET if one or more I2C errors occurred, the errors can
* be retrieved using @p i2cGetErrors().
* @retval MSG_TIMEOUT if a timeout occurred before operation end. <b>After a
* timeout the driver must be stopped and restarted
* because the bus is in an uncertain state</b>.
*
* @notapi
*/
msg_t i2c_lld_master_receive_timeout(I2CDriver *i2cp, i2caddr_t addr,
uint8_t *rxbuf, size_t rxbytes,
systime_t timeout) {
i2cp->errors = I2C_NO_ERROR;
i2cp->addr = addr;
i2cp->txbuf = NULL;
i2cp->txbytes = 0;
i2cp->txidx = 0;
i2cp->rxbuf = rxbuf;
i2cp->rxbytes = rxbytes;
i2cp->rxidx = 0;
/* Send START */
TWCR = ((1 << TWSTA) | (1 << TWINT) | (1 << TWEN) | (1 << TWIE));
return osalThreadSuspendTimeoutS(&i2cp->thread, TIME_INFINITE);
}
/**
* @brief Transmits data via the I2C bus as master.
*
* @param[in] i2cp pointer to the @p I2CDriver object
* @param[in] addr slave device address
* @param[in] txbuf pointer to the transmit buffer
* @param[in] txbytes number of bytes to be transmitted
* @param[out] rxbuf pointer to the receive buffer
* @param[in] rxbytes number of bytes to be received
* @param[in] timeout the number of ticks before the operation timeouts,
* the following special values are allowed:
* - @a TIME_INFINITE no timeout.
* .
* @return The operation status.
* @retval MSG_OK if the function succeeded.
* @retval MSG_RESET if one or more I2C errors occurred, the errors can
* be retrieved using @p i2cGetErrors().
* @retval MSG_TIMEOUT if a timeout occurred before operation end. <b>After a
* timeout the driver must be stopped and restarted
* because the bus is in an uncertain state</b>.
*
* @notapi
*/
msg_t i2c_lld_master_transmit_timeout(I2CDriver *i2cp, i2caddr_t addr,
const uint8_t *txbuf, size_t txbytes,
uint8_t *rxbuf, size_t rxbytes,
systime_t timeout) {
i2cp->errors = I2C_NO_ERROR;
i2cp->addr = addr;
i2cp->txbuf = txbuf;
i2cp->txbytes = txbytes;
i2cp->txidx = 0;
i2cp->rxbuf = rxbuf;
i2cp->rxbytes = rxbytes;
i2cp->rxidx = 0;
TWCR = ((1 << TWSTA) | (1 << TWINT) | (1 << TWEN) | (1 << TWIE));
return osalThreadSuspendTimeoutS(&i2cp->thread, TIME_INFINITE);
}
#endif /* HAL_USE_I2C */
/** @} */
|
