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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>
57 #if !CONFIG_I2C_DISABLE_OLD_API
59 INLINE bool i2c_bitbang_start(void)
70 void i2c_bitbang_stop(void)
78 bool i2c_bitbang_put(uint8_t _data)
81 uint16_t data = (_data << 1) | 1;
83 for (uint16_t i = 0x100; i != 0; i >>= 1)
102 bool i2c_bitbang_start_w(uint8_t id)
106 * Loop on the select write sequence: when the device is busy
107 * writing previously sent data it will reply to the SLA_W
108 * control byte with a NACK. In this case, we must
109 * keep trying until the deveice responds with an ACK.
111 ticks_t start = timer_clock();
112 while (i2c_bitbang_start())
114 if (i2c_bitbang_put(id))
116 else if (timer_clock() - start > ms_to_ticks(CONFIG_I2C_START_TIMEOUT))
118 LOG_ERR("Timeout on I2C start write\n");
121 //LOG_INFO("Rep start\n");
127 bool i2c_bitbang_start_r(uint8_t id)
130 if (i2c_bitbang_start())
132 if (i2c_bitbang_put(id))
135 LOG_ERR("NACK on I2c start read\n");
141 int i2c_bitbang_get(bool ack)
144 for (uint8_t i = 0x80; i != 0; i >>= 1)
168 /* avoid sign extension */
169 return (int)(uint8_t)data;
175 * Initialize i2c module.
177 void i2c_bitbang_init(void)
185 #endif /* !CONFIG_I2C_DISABLE_OLD_API */
190 #define I2C_DEV(i2c) ((int)((i2c)->hw))
192 static void i2c_bitbang_stop_1(struct I2c *i2c)
194 i2c_sdaLo(I2C_DEV(i2c));
195 i2c_sclHi(I2C_DEV(i2c));
196 i2c_halfbitDelay(I2C_DEV(i2c));
197 i2c_sdaHi(I2C_DEV(i2c));
200 INLINE bool i2c_bitbang_start_1(struct I2c *i2c)
202 i2c_sdaHi(I2C_DEV(i2c));
203 i2c_sclHi(I2C_DEV(i2c));
204 i2c_halfbitDelay(I2C_DEV(i2c));
205 i2c_sdaLo(I2C_DEV(i2c));
206 i2c_halfbitDelay(I2C_DEV(i2c));
208 return !i2c_sdaIn(I2C_DEV(i2c));
212 static uint8_t i2c_bitbang_getc(struct I2c *i2c)
215 for (uint8_t i = 0x80; i != 0; i >>= 1)
217 i2c_sclLo(I2C_DEV(i2c));
218 i2c_halfbitDelay(I2C_DEV(i2c));
219 i2c_sclHi(I2C_DEV(i2c));
220 if (i2c_sdaIn(I2C_DEV(i2c)))
225 i2c_halfbitDelay(I2C_DEV(i2c));
227 i2c_sclLo(I2C_DEV(i2c));
229 /* Generate ACK/NACK */
230 if (i2c->xfer_size > 1)
231 i2c_sdaLo(I2C_DEV(i2c));
233 i2c_sdaHi(I2C_DEV(i2c));
235 i2c_halfbitDelay(I2C_DEV(i2c));
236 i2c_sclHi(I2C_DEV(i2c));
237 i2c_halfbitDelay(I2C_DEV(i2c));
238 i2c_sclLo(I2C_DEV(i2c));
239 i2c_sdaHi(I2C_DEV(i2c));
241 /* Generate stop condition (if requested) */
242 if ((i2c->xfer_size == 1) && (i2c->flags & I2C_STOP))
243 i2c_bitbang_stop_1(i2c);
248 static void i2c_bitbang_putc(struct I2c *i2c, uint8_t _data)
251 uint16_t data = (_data << 1) | 1;
253 for (uint16_t i = 0x100; i != 0; i >>= 1)
255 i2c_sclLo(I2C_DEV(i2c));
257 i2c_sdaHi(I2C_DEV(i2c));
259 i2c_sdaLo(I2C_DEV(i2c));
260 i2c_halfbitDelay(I2C_DEV(i2c));
262 i2c_sclHi(I2C_DEV(i2c));
263 i2c_halfbitDelay(I2C_DEV(i2c));
266 bool ack = !i2c_sdaIn(I2C_DEV(i2c));
267 i2c_sclLo(I2C_DEV(i2c));
268 i2c_halfbitDelay(I2C_DEV(i2c));
272 LOG_ERR("NO ACK received\n");
273 i2c->errors |= I2C_NO_ACK;
276 /* Generate stop condition (if requested) */
277 if (((i2c->xfer_size == 1) && (i2c->flags & I2C_STOP)) || i2c->errors)
278 i2c_bitbang_stop_1(i2c);
282 static void i2c_bitbang_start_2(struct I2c *i2c, uint16_t slave_addr)
284 if (i2c->flags & I2C_START_R)
285 slave_addr |= I2C_READBIT;
287 slave_addr &= ~I2C_READBIT;
290 * Loop on the select write sequence: when the device is busy
291 * writing previously sent data it will reply to the SLA_W
292 * control byte with a NACK. In this case, we must
293 * keep trying until the deveice responds with an ACK.
295 ticks_t start = timer_clock();
296 while (i2c_bitbang_start_1(i2c))
298 i2c_bitbang_putc(i2c, slave_addr);
300 if (!(i2c->errors & I2C_NO_ACK))
302 else if (timer_clock() - start > ms_to_ticks(CONFIG_I2C_START_TIMEOUT))
304 LOG_ERR("Timeout on I2C start\n");
305 i2c->errors |= I2C_START_TIMEOUT;
306 i2c_bitbang_stop_1(i2c);
311 LOG_ERR("START arbitration lost\n");
312 i2c->errors |= I2C_ARB_LOST;
313 i2c_bitbang_stop_1(i2c);
318 static const I2cVT i2c_bitbang_vt =
320 .start = i2c_bitbang_start_2,
321 .getc = i2c_bitbang_getc,
322 .putc = i2c_bitbang_putc,
323 .write = i2c_genericWrite,
324 .read = i2c_genericRead,
329 * Initialize i2c module.
331 void i2c_hw_bitbangInit(I2c *i2c, int dev)
334 i2c->hw = (struct I2cHardware *)(dev - I2C_BITBANG0);
335 i2c->vt = &i2c_bitbang_vt;
337 i2c_bitbang_init(I2C_DEV(i2c));
338 i2c_sdaHi(I2C_DEV(i2c));
339 i2c_sclHi(I2C_DEV(i2c));