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29 * Copyright 2005 Develer S.r.l. (http://www.develer.com/)
33 * \brief I2C bitbang driver (implementation)
35 * \author Francesco Sacchi <batt@develer.com>
36 * \author Daniele Basile <asterix@develer.com>
39 #include "hw/hw_i2c_bitbang.h"
41 #include "cfg/cfg_i2c.h"
43 #define LOG_LEVEL I2C_LOG_LEVEL
44 #define LOG_FORMAT I2C_LOG_FORMAT
47 #include <cfg/macros.h>
48 #include <cfg/module.h>
50 #include <drv/timer.h>
58 INLINE bool i2c_bitbang_start(void)
69 void i2c_bitbang_stop(void)
77 bool i2c_bitbang_put(uint8_t _data)
80 uint16_t data = (_data << 1) | 1;
82 for (uint16_t i = 0x100; i != 0; i >>= 1)
101 bool i2c_bitbang_start_w(uint8_t id)
105 * Loop on the select write sequence: when the device is busy
106 * writing previously sent data it will reply to the SLA_W
107 * control byte with a NACK. In this case, we must
108 * keep trying until the deveice responds with an ACK.
110 ticks_t start = timer_clock();
111 while (i2c_bitbang_start())
113 if (i2c_bitbang_put(id))
115 else if (timer_clock() - start > ms_to_ticks(CONFIG_I2C_START_TIMEOUT))
117 LOG_ERR("Timeout on I2C start write\n");
120 //LOG_INFO("Rep start\n");
126 bool i2c_bitbang_start_r(uint8_t id)
129 if (i2c_bitbang_start())
131 if (i2c_bitbang_put(id))
134 LOG_ERR("NACK on I2c start read\n");
140 int i2c_bitbang_get(bool ack)
143 for (uint8_t i = 0x80; i != 0; i >>= 1)
167 /* avoid sign extension */
168 return (int)(uint8_t)data;
174 * Initialize i2c module.
176 void i2c_bitbang_init(void)
189 #define I2C_DEV(i2c) ((int)((i2c)->hw))
191 static void i2c_bitbang_stop_1(struct I2c *i2c)
193 i2c_hw_sdaLo(I2C_DEV(i2c));
194 i2c_hw_sclHi(I2C_DEV(i2c));
195 i2c_hw_halfbitDelay(I2C_DEV(i2c));
196 i2c_hw_sdaHi(I2C_DEV(i2c));
199 INLINE bool i2c_bitbang_start_1(struct I2c *i2c)
201 i2c_hw_sdaHi(I2C_DEV(i2c));
202 i2c_hw_sclHi(I2C_DEV(i2c));
203 i2c_hw_halfbitDelay(I2C_DEV(i2c));
204 i2c_hw_sdaLo(I2C_DEV(i2c));
205 i2c_hw_halfbitDelay(I2C_DEV(i2c));
207 return !i2c_hw_sdaIn(I2C_DEV(i2c));
211 static uint8_t i2c_bitbang_getc(struct I2c *i2c)
214 for (uint8_t i = 0x80; i != 0; i >>= 1)
216 i2c_hw_sclLo(I2C_DEV(i2c));
217 i2c_hw_halfbitDelay(I2C_DEV(i2c));
218 i2c_hw_sclHi(I2C_DEV(i2c));
219 if (i2c_hw_sdaIn(I2C_DEV(i2c)))
224 i2c_hw_halfbitDelay(I2C_DEV(i2c));
226 i2c_hw_sclLo(I2C_DEV(i2c));
228 /* Generate ACK/NACK */
229 if (i2c->xfer_size > 1)
230 i2c_hw_sdaLo(I2C_DEV(i2c));
232 i2c_hw_sdaHi(I2C_DEV(i2c));
234 i2c_hw_halfbitDelay(I2C_DEV(i2c));
235 i2c_hw_sclHi(I2C_DEV(i2c));
236 i2c_hw_halfbitDelay(I2C_DEV(i2c));
237 i2c_hw_sclLo(I2C_DEV(i2c));
238 i2c_hw_sdaHi(I2C_DEV(i2c));
240 /* Generate stop condition (if requested) */
241 if ((i2c->xfer_size == 1) && (i2c->flags & I2C_STOP))
242 i2c_bitbang_stop_1(i2c);
247 static void i2c_bitbang_putc(struct I2c *i2c, uint8_t _data)
250 uint16_t data = (_data << 1) | 1;
252 for (uint16_t i = 0x100; i != 0; i >>= 1)
254 i2c_hw_sclLo(I2C_DEV(i2c));
256 i2c_hw_sdaHi(I2C_DEV(i2c));
258 i2c_hw_sdaLo(I2C_DEV(i2c));
259 i2c_hw_halfbitDelay(I2C_DEV(i2c));
261 i2c_hw_sclHi(I2C_DEV(i2c));
262 i2c_hw_halfbitDelay(I2C_DEV(i2c));
265 bool ack = !i2c_hw_sdaIn(I2C_DEV(i2c));
266 i2c_hw_sclLo(I2C_DEV(i2c));
267 i2c_hw_halfbitDelay(I2C_DEV(i2c));
271 LOG_ERR("NO ACK received\n");
272 i2c->errors |= I2C_NO_ACK;
275 /* Generate stop condition (if requested) */
276 if (((i2c->xfer_size == 1) && (i2c->flags & I2C_STOP)) || i2c->errors)
277 i2c_bitbang_stop_1(i2c);
281 static void i2c_bitbang_start_2(struct I2c *i2c, uint16_t slave_addr)
283 if (i2c->flags & I2C_START_R)
284 slave_addr |= I2C_READBIT;
286 slave_addr &= ~I2C_READBIT;
289 * Loop on the select write sequence: when the device is busy
290 * writing previously sent data it will reply to the SLA_W
291 * control byte with a NACK. In this case, we must
292 * keep trying until the deveice responds with an ACK.
294 ticks_t start = timer_clock();
295 while (i2c_bitbang_start_1(i2c))
297 i2c_bitbang_putc(i2c, slave_addr);
299 if (!(i2c->errors & I2C_NO_ACK))
301 else if (timer_clock() - start > ms_to_ticks(CONFIG_I2C_START_TIMEOUT))
303 LOG_ERR("Timeout on I2C start\n");
304 i2c->errors |= I2C_START_TIMEOUT;
305 i2c_bitbang_stop_1(i2c);
310 LOG_ERR("START arbitration lost\n");
311 i2c->errors |= I2C_ARB_LOST;
312 i2c_bitbang_stop_1(i2c);
317 static const I2cVT i2c_bitbang_vt =
319 .start = i2c_bitbang_start_2,
320 .getc = i2c_bitbang_getc,
321 .putc = i2c_bitbang_putc,
322 .write = i2c_genericWrite,
323 .read = i2c_genericRead,
328 * Initialize i2c module.
330 void i2c_hw_bitbangInit(I2c *i2c, int dev)
333 i2c->hw = (struct I2cHardware *)(dev - I2C_BITBANG0);
334 i2c->vt = &i2c_bitbang_vt;
336 i2c_hw_bitbang_init(I2C_DEV(i2c));
337 i2c_hw_sdaHi(I2C_DEV(i2c));
338 i2c_hw_sclHi(I2C_DEV(i2c));