diff --git a/boards/arduino-atmega-common/include/periph_conf.h b/boards/arduino-atmega-common/include/periph_conf.h
index 12043bfa661e75aae01ee51918301864a90a78dd..71b69036938ab9f6afef31c9dfe256217f6b2d3c 100644
--- a/boards/arduino-atmega-common/include/periph_conf.h
+++ b/boards/arduino-atmega-common/include/periph_conf.h
@@ -144,12 +144,9 @@ extern "C" {
/** @} */
/**
- * @name I2C configuration
- * @{
+ * @brief I2C configuration
*/
#define I2C_NUMOF 1
-#define I2C_0_EN 1
-#define I2C_IRQ_PRIO 1
#ifdef __cplusplus
}
diff --git a/boards/waspmote-pro/include/periph_conf.h b/boards/waspmote-pro/include/periph_conf.h
index 25f06d7ffad27d5500b80a1ae4968f45f1267e4b..0caa7548cf78e43fd185f483c2554eac71016b80 100644
--- a/boards/waspmote-pro/include/periph_conf.h
+++ b/boards/waspmote-pro/include/periph_conf.h
@@ -105,12 +105,9 @@ extern "C" {
/** @} */
/**
- * @name I2C configuration
- * @{
+ * @brief I2C configuration
*/
#define I2C_NUMOF 1
-#define I2C_0_EN 1
-#define I2C_IRQ_PRIO 1
#ifdef __cplusplus
}
diff --git a/cpu/atmega1281/include/periph_cpu.h b/cpu/atmega1281/include/periph_cpu.h
index 3d7c73861e10606bc4e415994a729137addd117a..3d74de0ec46ee7a664b67e75996ecaef230a53b3 100644
--- a/cpu/atmega1281/include/periph_cpu.h
+++ b/cpu/atmega1281/include/periph_cpu.h
@@ -42,6 +42,15 @@ enum {
PORT_G = 6, /**< port G */
};
+/**
+ * @name Defines for the I2C interface
+ * @{
+ */
+#define I2C_PORT_REG PORTD
+#define I2C_PIN_MASK (1 << PORTD0) | (1 << PORTD1)
+#define I2C_POWER_REG PRR0
+/** @} */
+
#ifdef __cplusplus
}
#endif
diff --git a/cpu/atmega2560/include/periph_cpu.h b/cpu/atmega2560/include/periph_cpu.h
index 719eb9a7c06e3ee30b03e16d01ba760e778003e9..83257818d68ee3299e68edc29f37fbb69ffc798c 100644
--- a/cpu/atmega2560/include/periph_cpu.h
+++ b/cpu/atmega2560/include/periph_cpu.h
@@ -44,6 +44,15 @@ enum {
PORT_L = 10 /**< port L */
};
+/**
+ * @name Defines for the I2C interface
+ * @{
+ */
+#define I2C_PORT_REG PORTD
+#define I2C_PIN_MASK (1 << PORTD0) | (1 << PORTD1)
+#define I2C_POWER_REG PRR0
+/** @} */
+
#ifdef __cplusplus
}
#endif
diff --git a/cpu/atmega328p/include/periph_cpu.h b/cpu/atmega328p/include/periph_cpu.h
index 2a7ff88f9f5952723442da084a953f51fefba87e..3555d5b0ef7ff7a5a087f58e31643ab9dde287f8 100644
--- a/cpu/atmega328p/include/periph_cpu.h
+++ b/cpu/atmega328p/include/periph_cpu.h
@@ -41,6 +41,15 @@ enum {
PORT_D = 3 /**< port D */
};
+/**
+ * @name Defines for the I2C interface
+ * @{
+ */
+#define I2C_PORT_REG PORTC
+#define I2C_PIN_MASK (1 << PORTC4) | (1 << PORTC5)
+#define I2C_POWER_REG PRR
+/** @} */
+
#ifdef __cplusplus
}
#endif
diff --git a/cpu/atmega_common/periph/i2c.c b/cpu/atmega_common/periph/i2c.c
index fc7509f63f563e30a4007dd2b2c4e03e067b9ef6..92c1dad11630855032c26246a9fd12cb2398594c 100644
--- a/cpu/atmega_common/periph/i2c.c
+++ b/cpu/atmega_common/periph/i2c.c
@@ -7,13 +7,14 @@
*/
/**
- * @addtogroup driver_periph
+ * @ingroup cpu_atmega_common
+ * @ingroup drivers_periph_i2c
* @{
*
* @file
* @brief Low-level I2C driver implementation fot atmega common
*
- * @note This implementation only implements the 7-bit addressing mode.
+ * @note This implementation only implements the 7-bit addressing mode.
*
* @author Dimitri Nahm <dimitri.nahm@haw-hamburg.de>
*
@@ -24,38 +25,35 @@
#include "cpu.h"
#include "mutex.h"
+#include "assert.h"
#include "periph/i2c.h"
#include "periph_conf.h"
-#define ENABLE_DEBUG (0)
#include "debug.h"
-
-#define MT_START 0x08
-#define MT_ADDRESS_ACK 0x18
-#define MT_DATA_ACK 0x28
-#define MR_ADDRESS_ACK 0x40
+#define ENABLE_DEBUG (0)
/* guard file in case no I2C device is defined */
#if I2C_NUMOF
+#define MT_START 0x08
+#define MT_START_REPEATED 0x10
+#define MT_ADDRESS_ACK 0x18
+#define MT_DATA_ACK 0x28
+#define MR_ADDRESS_ACK 0x40
+
/* static function definitions */
static int _start(uint8_t address, uint8_t rw_flag);
static int _write(const uint8_t *data, int length);
static void _stop(void);
-/**
- * @brief Array holding one pre-initialized mutex for each I2C device
- */
-static mutex_t locks[] = {
-#if I2C_0_EN
- [I2C_0] = MUTEX_INIT,
-#endif
-};
+static mutex_t lock = MUTEX_INIT;
int i2c_init_master(i2c_t dev, i2c_speed_t speed)
{
- /* TWI Bit Rate Register - division factor for the bit rate generator*/
- int twibrr;
+ /* TWI Bit Rate Register - division factor for the bit rate generator */
+ uint8_t twibrr;
+ /* TWI Prescaler Bits - default 0 */
+ uint8_t twipb = 0;
/* check if the line is valid */
if (dev >= I2C_NUMOF) {
@@ -64,25 +62,49 @@ int i2c_init_master(i2c_t dev, i2c_speed_t speed)
/* calculate speed configuration */
switch (speed) {
+
+ case I2C_SPEED_LOW:
+ if (CLOCK_CORECLOCK > 20000000U || CLOCK_CORECLOCK < 1000000U) {
+ return -2;
+ }
+ twibrr = ((CLOCK_CORECLOCK/10000)-16)/(2*4); // CLK Prescaler 4
+ twipb = 1;
+ break;
+
case I2C_SPEED_NORMAL:
+ if (CLOCK_CORECLOCK > 50000000U || CLOCK_CORECLOCK < 2000000U) {
+ return -2;
+ }
twibrr = ((CLOCK_CORECLOCK/100000)-16)/2;
break;
case I2C_SPEED_FAST:
+ if (CLOCK_CORECLOCK < 7500000U) {
+ return -2;
+ }
twibrr = ((CLOCK_CORECLOCK/400000)-16)/2;
break;
+ case I2C_SPEED_FAST_PLUS:
+ if (CLOCK_CORECLOCK < 18000000U) {
+ return -2;
+ }
+ twibrr = ((CLOCK_CORECLOCK/1000000)-16)/2;
+ break;
+
+ case I2C_SPEED_HIGH:
+ if (CLOCK_CORECLOCK < 62000000U) {
+ return -2;
+ }
+ twibrr = ((CLOCK_CORECLOCK/3400000)-16)/2;
+ break;
+
default:
return -2;
}
/* set pull-up on SCL and SDA */
- #if defined (CPU_ATMEGA2560) || defined (CPU_ATMEGA1281)
- PORTD |= (1 << PORTD0) | (1 << PORTD1);
- #endif
- #ifdef CPU_ATMEGA328P
- PORTC |= (1 << PORTC4) | (1 << PORTC5);
- #endif
+ I2C_PORT_REG |= (I2C_PIN_MASK);
/* enable I2C clock */
i2c_poweron(dev);
@@ -90,7 +112,9 @@ int i2c_init_master(i2c_t dev, i2c_speed_t speed)
/* disable device */
TWCR &= ~(1 << TWEN);
/* configure I2C clock */
- TWBR = twibrr;
+ TWBR = twibrr; // Set TWI Bit Rate Register
+ TWSR &= ~(0x03); // Reset TWI Prescaler Bits
+ TWSR |= twipb; // Set TWI Prescaler Bits
/* enable device */
TWCR |= (1 << TWEN);
@@ -99,19 +123,15 @@ int i2c_init_master(i2c_t dev, i2c_speed_t speed)
int i2c_acquire(i2c_t dev)
{
- if (dev >= I2C_NUMOF) {
- return -1;
- }
- mutex_lock(&locks[dev]);
+ assert(dev < I2C_NUMOF);
+ mutex_lock(&lock);
return 0;
}
int i2c_release(i2c_t dev)
{
- if (dev >= I2C_NUMOF) {
- return -1;
- }
- mutex_unlock(&locks[dev]);
+ assert(dev < I2C_NUMOF);
+ mutex_unlock(&lock);
return 0;
}
@@ -124,24 +144,24 @@ int i2c_read_bytes(i2c_t dev, uint8_t address, void *data, int length)
{
uint8_t *my_data = data;
- if ((unsigned int)dev >= I2C_NUMOF) {
- return -1;
- }
+ assert((dev < I2C_NUMOF) && (length > 0));
/* send start condition and slave address */
- if (_start(address, I2C_FLAG_READ) != 0)
+ if (_start(address, I2C_FLAG_READ) != 0) {
return 0;
+ }
for (int i = 0; i < length; i++) {
/* Send NACK for last received byte */
- if ((length-i) == 1)
+ if ((length - i) == 1) {
TWCR = (1 << TWEN) | (1 << TWINT);
- else
+ }
+ else {
TWCR = (1 << TWEA) | (1 << TWEN) | (1 << TWINT);
+ }
DEBUG("Wait for byte %i\n", i+1);
/* Wait for TWINT Flag set. This indicates that DATA has been received.*/
- while (!(TWCR & (1 << TWINT)))
- {}
+ while (!(TWCR & (1 << TWINT))) {}
/* receive data byte */
my_data[i] = TWDR;
DEBUG("Byte %i received\n", i+1);
@@ -160,13 +180,12 @@ int i2c_read_reg(i2c_t dev, uint8_t address, uint8_t reg, void *data)
int i2c_read_regs(i2c_t dev, uint8_t address, uint8_t reg, void *data, int length)
{
- if ((unsigned int)dev >= I2C_NUMOF) {
- return -1;
- }
+ assert((dev < I2C_NUMOF) && (length > 0));
/* start transmission and send slave address */
- if (_start(address, I2C_FLAG_WRITE) != 0)
+ if (_start(address, I2C_FLAG_WRITE) != 0) {
return 0;
+ }
/* send register address and wait for complete transfer to be finished*/
if (_write(®, 1) != 1) {
@@ -174,8 +193,6 @@ int i2c_read_regs(i2c_t dev, uint8_t address, uint8_t reg, void *data, int lengt
return 0;
}
- _stop();
-
/* now start a new start condition and receive data */
return i2c_read_bytes(dev, address, data, length);
}
@@ -189,13 +206,12 @@ int i2c_write_bytes(i2c_t dev, uint8_t address, const void *data, int length)
{
int bytes = 0;
- if ((unsigned int)dev >= I2C_NUMOF) {
- return -1;
- }
+ assert((dev < I2C_NUMOF) && (length > 0));
/* start transmission and send slave address */
- if (_start(address, I2C_FLAG_WRITE) != 0)
+ if (_start(address, I2C_FLAG_WRITE) != 0) {
return 0;
+ }
/* send out data bytes */
bytes = _write(data, length);
@@ -208,10 +224,6 @@ int i2c_write_bytes(i2c_t dev, uint8_t address, const void *data, int length)
int i2c_write_reg(i2c_t dev, uint8_t address, uint8_t reg, uint8_t data)
{
- if ((unsigned int)dev >= I2C_NUMOF) {
- return -1;
- }
-
return i2c_write_regs(dev, address, reg, &data, 1);
}
@@ -219,17 +231,17 @@ int i2c_write_regs(i2c_t dev, uint8_t address, uint8_t reg, const void *data, in
{
int bytes = 0;
- if ((unsigned int)dev >= I2C_NUMOF) {
- return -1;
- }
+ assert((dev < I2C_NUMOF) && (length > 0));
/* start transmission and send slave address */
- if (_start(address, I2C_FLAG_WRITE) != 0)
+ if (_start(address, I2C_FLAG_WRITE) != 0) {
return 0;
+ }
/* send register address and wait for complete transfer to be finished*/
- if (_write(®, 1))
+ if (_write(®, 1)) {
/* write data to register */
bytes = _write(data, length);
+ }
/* finish transfer */
_stop();
/* return number of bytes send */
@@ -238,26 +250,14 @@ int i2c_write_regs(i2c_t dev, uint8_t address, uint8_t reg, const void *data, in
void i2c_poweron(i2c_t dev)
{
- if (dev < I2C_NUMOF) {
- #if defined (CPU_ATMEGA2560) || defined (CPU_ATMEGA1281)
- PRR0 &= ~(1 << PRTWI);
- #endif
- #ifdef CPU_ATMEGA328P
- PRR &= ~(1 << PRTWI);
- #endif
- }
+ assert(dev < I2C_NUMOF);
+ I2C_POWER_REG &= ~(1 << PRTWI);
}
void i2c_poweroff(i2c_t dev)
{
- if (dev < I2C_NUMOF) {
- #if defined (CPU_ATMEGA2560) || defined (CPU_ATMEGA1281)
- PRR0 |= (1 << PRTWI);
- #endif
- #ifdef CPU_ATMEGA328P
- PRR |= (1 << PRTWI);
- #endif
- }
+ assert(dev < I2C_NUMOF);
+ I2C_POWER_REG |= (1 << PRTWI);
}
static int _start(uint8_t address, uint8_t rw_flag)
@@ -267,36 +267,41 @@ static int _start(uint8_t address, uint8_t rw_flag)
DEBUG("START condition transmitted\n");
/* Wait for TWINT Flag set. This indicates that the START has been
- transmitted, and ACK/NACK has been received.*/
- while (!(TWCR & (1 << TWINT)))
- {}
+ * transmitted, and ACK/NACK has been received.*/
+ while (!(TWCR & (1 << TWINT))) {}
/* Check value of TWI Status Register. Mask prescaler bits.
- If status different from START go to ERROR */
- if ((TWSR & 0xF8) != MT_START) {
- DEBUG("I2C Status Register is different from START\n");
+ * If status different from START go to ERROR */
+ if ((TWSR & 0xF8) == MT_START) {
+ DEBUG("I2C Status is: START\n");
+ }
+ else if ((TWSR & 0xF8) == MT_START_REPEATED) {
+ DEBUG("I2C Status is: START REPEATED\n");
+ }
+ else {
+ DEBUG("I2C Status Register is different from START/START_REPEATED\n");
_stop();
return -1;
}
- else
- DEBUG("I2C Status Register is: START\n");
+
/* Load ADDRESS and R/W Flag into TWDR Register.
- Clear TWINT bit in TWCR to start transmission of ADDRESS */
+ * Clear TWINT bit in TWCR to start transmission of ADDRESS */
TWDR = (address << 1) | rw_flag;
TWCR = (1 << TWINT) | (1 << TWEN);
DEBUG("ADDRESS and FLAG transmitted\n");
/* Wait for TWINT Flag set. This indicates that ADDRESS has been transmitted.*/
- while (!(TWCR & (1 << TWINT)))
- {}
+ while (!(TWCR & (1 << TWINT))) {}
/* Check value of TWI Status Register. Mask prescaler bits.
- If status different from ADDRESS ACK go to ERROR */
- if ((TWSR & 0xF8) == MT_ADDRESS_ACK)
+ * If status different from ADDRESS ACK go to ERROR */
+ if ((TWSR & 0xF8) == MT_ADDRESS_ACK) {
DEBUG("ACK has been received for ADDRESS (write)\n");
- else if ((TWSR & 0xF8) == MR_ADDRESS_ACK)
+ }
+ else if ((TWSR & 0xF8) == MR_ADDRESS_ACK) {
DEBUG("ACK has been received for ADDRESS (read)\n");
+ }
else {
DEBUG("NOT ACK has been received for ADDRESS\n");
_stop();
@@ -308,38 +313,36 @@ static int _start(uint8_t address, uint8_t rw_flag)
static int _write(const uint8_t *data, int length)
{
- int i = 0;
-
- for (i = 0; i < length; i++) {
+ for (int i = 0; i < length; i++) {
/* Load DATA into TWDR Register.
- Clear TWINT bit in TWCR to start transmission of data */
+ * Clear TWINT bit in TWCR to start transmission of data */
TWDR = data[i];
TWCR = (1 << TWINT) | (1 << TWEN);
DEBUG("Byte %i transmitted\n", i+1);
/* Wait for TWINT Flag set. This indicates that DATA has been transmitted.*/
- while (!(TWCR & (1 << TWINT)))
- {}
+ while (!(TWCR & (1 << TWINT))) {}
/* Check value of TWI Status Register. Mask prescaler bits. If status
- different from MT_DATA_ACK, return number of transmitted bytes */
+ * different from MT_DATA_ACK, return number of transmitted bytes */
if ((TWSR & 0xF8) != MT_DATA_ACK) {
DEBUG("NACK has been received for BYTE %i\n", i+1);
return i;
}
- else
+ else {
DEBUG("ACK has been received for BYTE %i\n", i+1);
+ }
}
- return i;
+ return length;
}
static void _stop(void)
{
/* Reset I2C Interrupt Flag and transmit STOP condition */
TWCR = (1 << TWINT) | (1 << TWSTO) | (1 << TWEN);
- while (TWCR & (1 << TWSTO))
- {}
+ /* Wait for STOP Flag reset. This indicates that STOP has been transmitted.*/
+ while (TWCR & (1 << TWSTO)) {}
DEBUG("STOP condition transmitted\n");
TWCR = 0;
}