*
* \brief I2C bitbang driver (implementation)
*
- * \version $Id: adc.c 1604 2008-08-10 17:19:51Z bernie $
* \author Francesco Sacchi <batt@develer.com>
+ * \author Daniele Basile <asterix@develer.com>
*/
-#include "i2c.h"
-#include "timer.h"
#include "hw/hw_i2c_bitbang.h"
-#define I2C_PERIOD DIV_ROUND(500000UL / CONFIG_I2C_FREQ)
+#include "cfg/cfg_i2c.h"
-INLINE bool i2c_start(void)
+#define LOG_LEVEL I2C_LOG_LEVEL
+#define LOG_FORMAT I2C_LOG_FORMAT
+
+#include <cfg/log.h>
+#include <cfg/macros.h>
+#include <cfg/module.h>
+
+#include <drv/timer.h>
+#include <drv/i2c.h>
+
+#include <cpu/irq.h>
+
+#include <cpu/attr.h>
+
+
+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;
}
-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;
/*
* 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");
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;
}
/**
* Initialize i2c module.
*/
-void i2c_init(void)
+void i2c_bitbang_init(void)
{
+ MOD_CHECK(timer);
I2C_BITBANG_HW_INIT;
SDA_HI;
SCL_HI;
MOD_INIT(i2c);
}
+
+/*
+ * New I2C API
+ */
+#define I2C_DEV(i2c) ((int)((i2c)->hw))
+
+static void i2c_bitbang_stop_1(struct I2c *i2c)
+{
+ i2c_hw_sdaLo(I2C_DEV(i2c));
+ i2c_hw_sclHi(I2C_DEV(i2c));
+ i2c_hw_halfbitDelay(I2C_DEV(i2c));
+ i2c_hw_sdaHi(I2C_DEV(i2c));
+}
+
+INLINE bool i2c_bitbang_start_1(struct I2c *i2c)
+{
+ i2c_hw_sdaHi(I2C_DEV(i2c));
+ i2c_hw_sclHi(I2C_DEV(i2c));
+ i2c_hw_halfbitDelay(I2C_DEV(i2c));
+ i2c_hw_sdaLo(I2C_DEV(i2c));
+ i2c_hw_halfbitDelay(I2C_DEV(i2c));
+
+ return !i2c_hw_sdaIn(I2C_DEV(i2c));
+}
+
+
+static uint8_t i2c_bitbang_getc(struct I2c *i2c)
+{
+ uint8_t data = 0;
+ for (uint8_t i = 0x80; i != 0; i >>= 1)
+ {
+ i2c_hw_sclLo(I2C_DEV(i2c));
+ i2c_hw_halfbitDelay(I2C_DEV(i2c));
+ i2c_hw_sclHi(I2C_DEV(i2c));
+ if (i2c_hw_sdaIn(I2C_DEV(i2c)))
+ data |= i;
+ else
+ data &= ~i;
+
+ i2c_hw_halfbitDelay(I2C_DEV(i2c));
+ }
+ i2c_hw_sclLo(I2C_DEV(i2c));
+
+ /* Generate ACK/NACK */
+ if (i2c->xfer_size > 1)
+ i2c_hw_sdaLo(I2C_DEV(i2c));
+ else
+ i2c_hw_sdaHi(I2C_DEV(i2c));
+
+ i2c_hw_halfbitDelay(I2C_DEV(i2c));
+ i2c_hw_sclHi(I2C_DEV(i2c));
+ i2c_hw_halfbitDelay(I2C_DEV(i2c));
+ i2c_hw_sclLo(I2C_DEV(i2c));
+ i2c_hw_sdaHi(I2C_DEV(i2c));
+
+ /* Generate stop condition (if requested) */
+ if ((i2c->xfer_size == 1) && (i2c->flags & I2C_STOP))
+ i2c_bitbang_stop_1(i2c);
+
+ return data;
+}
+
+static void i2c_bitbang_putc(struct I2c *i2c, uint8_t _data)
+{
+ /* Add ACK bit */
+ uint16_t data = (_data << 1) | 1;
+
+ for (uint16_t i = 0x100; i != 0; i >>= 1)
+ {
+ i2c_hw_sclLo(I2C_DEV(i2c));
+ if (data & i)
+ i2c_hw_sdaHi(I2C_DEV(i2c));
+ else
+ i2c_hw_sdaLo(I2C_DEV(i2c));
+ i2c_hw_halfbitDelay(I2C_DEV(i2c));
+
+ i2c_hw_sclHi(I2C_DEV(i2c));
+ i2c_hw_halfbitDelay(I2C_DEV(i2c));
+ }
+
+ bool ack = !i2c_hw_sdaIn(I2C_DEV(i2c));
+ i2c_hw_sclLo(I2C_DEV(i2c));
+ i2c_hw_halfbitDelay(I2C_DEV(i2c));
+
+ 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_1(i2c);
+}
+
+
+static void i2c_bitbang_start_2(struct I2c *i2c, uint16_t slave_addr)
+{
+ 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_1(i2c))
+ {
+ i2c_bitbang_putc(i2c, slave_addr);
+
+ if (!(i2c->errors & I2C_NO_ACK))
+ 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_1(i2c);
+ return;
+ }
+ }
+
+ LOG_ERR("START arbitration lost\n");
+ i2c->errors |= I2C_ARB_LOST;
+ i2c_bitbang_stop_1(i2c);
+ return;
+}
+
+
+static const I2cVT i2c_bitbang_vt =
+{
+ .start = i2c_bitbang_start_2,
+ .getc = i2c_bitbang_getc,
+ .putc = i2c_bitbang_putc,
+ .write = i2c_genericWrite,
+ .read = i2c_genericRead,
+};
+
+
+/**
+ * Initialize i2c module.
+ */
+void i2c_hw_bitbangInit(I2c *i2c, int dev)
+{
+ MOD_CHECK(timer);
+ i2c->hw = (struct I2cHardware *)(dev - I2C_BITBANG0);
+ i2c->vt = &i2c_bitbang_vt;
+
+ i2c_hw_bitbang_init(I2C_DEV(i2c));
+ i2c_hw_sdaHi(I2C_DEV(i2c));
+ i2c_hw_sclHi(I2C_DEV(i2c));
+}
+
projects / bertos.git / blobdiff