X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=bertos%2Fdrv%2Fi2c_bitbang.c;h=45847c93c4e598bc2f0d66106bd110294cdaa2ed;hb=d8e686668bfa23a83f2fa692d6931b144d1a2b5b;hp=7124389854430433cd2fcc2ef88fa472e2d92943;hpb=4f641b0adb067c5b233abc37b81787936a3bcacf;p=bertos.git diff --git a/bertos/drv/i2c_bitbang.c b/bertos/drv/i2c_bitbang.c index 71243898..45847c93 100644 --- a/bertos/drv/i2c_bitbang.c +++ b/bertos/drv/i2c_bitbang.c @@ -32,56 +32,68 @@ * * \brief I2C bitbang driver (implementation) * - * \version $Id: adc.c 1604 2008-08-10 17:19:51Z bernie $ * \author Francesco Sacchi */ #include "i2c.h" -#include "timer.h" -#include "hw/hw_i2c_bitbang.h" +#include "cfg/cfg_i2c.h" + +#define LOG_LEVEL I2C_LOG_LEVEL +#define LOG_FORMAT I2C_LOG_FORMAT + +#include +#include +#include -#define I2C_PERIOD DIV_ROUND(500000UL / CONFIG_I2C_FREQ) +#include +#include + +#include "hw/hw_i2c_bitbang.h" -INLINE bool i2c_start(void) +INLINE bool i2c_bitbang_start(void) { SDA_HI; SCL_HI; - timer_udelay(I2C_PERIOD); - SDA_LOW; - timer_udelay(I2C_PERIOD); - return !SDA; + I2C_HALFBIT_DELAY(); + SDA_LO; + I2C_HALFBIT_DELAY(); + + return !SDA_IN; } -INLINE void i2c_stop(void) +void i2c_bitbang_stop(void) { + SDA_LO; SCL_HI; - timer_udelay(I2C_PERIOD); + I2C_HALFBIT_DELAY(); SDA_HI; } -bool i2c_put(uint8_t _data) +bool i2c_bitbang_put(uint8_t _data) { + /* Add ACK bit */ uint16_t data = (_data << 1) | 1; - for (uint16_t i = 0x100; i >= 0; i >>= 1) + + for (uint16_t i = 0x100; i != 0; i >>= 1) { SCL_LO; - timer_udelay(I2C_PERIOD); if (data & i) SDA_HI; else SDA_LO; + I2C_HALFBIT_DELAY(); + SCL_HI; - timer_udelay(I2C_PERIOD); - ASSERT(SDA == (data & i)); + I2C_HALFBIT_DELAY(); } - bool ack = !SDA; - ASSERT(ack); + + bool ack = !SDA_IN; SCL_LO; - timer_udelay(I2C_PERIOD); + I2C_HALFBIT_DELAY(); return ack; } -bool i2c_start_w(uint8_t id) +bool i2c_bitbang_start_w(uint8_t id) { id &= ~I2C_READBIT; /* @@ -91,26 +103,27 @@ bool i2c_start_w(uint8_t id) * keep trying until the deveice responds with an ACK. */ ticks_t start = timer_clock(); - while (i2c_start()) + while (i2c_bitbang_start()) { - if (i2c_put(id)) + if (i2c_bitbang_put(id)) return true; - else if (timer_clock() - start > ms_to_ticks(CONFIG_TWI_START_TIMEOUT)) + else if (timer_clock() - start > ms_to_ticks(CONFIG_I2C_START_TIMEOUT)) { LOG_ERR("Timeout on I2C start write\n"); break; } + //LOG_INFO("Rep start\n"); } return false; } -bool i2c_start_r(uint8_t id) +bool i2c_bitbang_start_r(uint8_t id) { id |= I2C_READBIT; - if (i2c_start()) + if (i2c_bitbang_start()) { - if (i2c_put(id)) + if (i2c_bitbang_put(id)) return true; LOG_ERR("NACK on I2c start read\n"); @@ -119,79 +132,163 @@ bool i2c_start_r(uint8_t id) return false; } -int i2c_get(bool ack) +int i2c_bitbang_get(bool ack) { uint8_t data = 0; - for (uint8_t i = 0x80; i >= 0; i >>= 1) + for (uint8_t i = 0x80; i != 0; i >>= 1) { SCL_LO; - timer_udelay(I2C_PERIOD); + I2C_HALFBIT_DELAY(); SCL_HI; - timer_udelay(I2C_PERIOD); - if (SDA) + if (SDA_IN) data |= i; + else + data &= ~i; + + I2C_HALFBIT_DELAY(); } SCL_LO; - timer_udelay(I2C_PERIOD); if (ack) SDA_LO; else SDA_HI; + I2C_HALFBIT_DELAY(); SCL_HI; + I2C_HALFBIT_DELAY(); + SCL_LO; + SDA_HI; /* avoid sign extension */ return (int)(uint8_t)data; } +MOD_DEFINE(i2c); + /** - * Send a sequence of bytes in master transmitter mode - * to the selected slave device through the I2C bus. - * - * \return true on success, false on error. + * Initialize i2c module. + */ +void i2c_bitbang_init(void) +{ + MOD_CHECK(timer); + I2C_BITBANG_HW_INIT; + SDA_HI; + SCL_HI; + MOD_INIT(i2c); +} + + +/* + * New I2C API */ -bool i2c_send(const void *_buf, size_t count) + +static void i2c_bitbang_stop(struct I2c *i2c) +{ + SDA_LO; + SCL_HI; + I2C_HALFBIT_DELAY(); + SDA_HI; +} + + +void i2c_bitbang_start(struct I2c *i2c, uint16_t slave_addr) { - const uint8_t *buf = (const uint8_t *)_buf; + if (i2c->flags & I2C_START_R) + slave_addr |= I2C_READBIT; + else + slave_addr &= ~I2C_READBIT; + + /* + * Loop on the select write sequence: when the device is busy + * writing previously sent data it will reply to the SLA_W + * control byte with a NACK. In this case, we must + * keep trying until the deveice responds with an ACK. + */ + ticks_t start = timer_clock(); + while (i2c_bitbang_start()) + { + if (i2c_bitbang_put(slave_addr)) + return; + else if (timer_clock() - start > ms_to_ticks(CONFIG_I2C_START_TIMEOUT)) + { + LOG_ERR("Timeout on I2C start\n"); + i2c->errors |= I2C_START_TIMEOUT; + i2c_bitbang_stop(i2c); + return; + } + } - while (count--) + LOG_ERR("START arbitration lost\n"); + i2c->errors |= I2C_ARB_LOST; + i2c_bitbang_stop(i2c); + return; +} + +uint8_t i2c_bitbang_get(struct I2c *i2c) +{ + uint8_t data = 0; + for (uint8_t i = 0x80; i != 0; i >>= 1) { - if (!i2c_put(*buf++)) - return false; + SCL_LO; + I2C_HALFBIT_DELAY(); + SCL_HI; + if (SDA_IN) + data |= i; + else + data &= ~i; + + I2C_HALFBIT_DELAY(); } - return true; + SCL_LO; + + /* Generate ACK/NACK */ + if (i2c->xfer_size > 1) + SDA_LO; + else + SDA_HI; + + I2C_HALFBIT_DELAY(); + SCL_HI; + I2C_HALFBIT_DELAY(); + SCL_LO; + SDA_HI; + + /* Generate stop condition (if requested) */ + if ((i2c->xfer_size == 1) && (i2c->flags & I2C_STOP)) + i2c_bitbang_stop(i2c); + + return data; } -/** - * Receive a sequence of one or more bytes from the - * selected slave device in master receive mode through - * the I2C bus. - * - * Received data is placed in \c buf. - * - * \note a NACK is automatically given on the last received - * byte. - * - * \return true on success, false on error - */ -bool i2c_recv(void *_buf, size_t count) +void i2c_bitbang_put(struct I2c *i2c, uint8_t _data) { - uint8_t *buf = (uint8_t *)_buf; + /* Add ACK bit */ + uint16_t data = (_data << 1) | 1; - while (count--) + for (uint16_t i = 0x100; i != 0; i >>= 1) { - /* - * The last byte read does not has an ACK - * to stop communication. - */ - int c = i2c_get(count); - - if (c == EOF) - return false; + SCL_LO; + if (data & i) + SDA_HI; else - *buf++ = c; + SDA_LO; + I2C_HALFBIT_DELAY(); + + SCL_HI; + I2C_HALFBIT_DELAY(); } - return true; -} + bool ack = !SDA_IN; + SCL_LO; + I2C_HALFBIT_DELAY(); + if (!ack) + { + LOG_ERR("NO ACK received\n"); + i2c->errors |= I2C_NO_ACK; + } + + /* Generate stop condition (if requested) */ + if (((i2c->xfer_size == 1) && (i2c->flags & I2C_STOP)) || i2c->errors) + i2c_bitbang_stop(i2c); +}