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@@ -7,43 +7,44 @@
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#include "i2c_master.h"
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#include "timer.h"
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+#include "wait.h"
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#ifndef F_SCL
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-#define F_SCL 400000UL // SCL frequency
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+# define F_SCL 400000UL // SCL frequency
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#endif
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#define Prescaler 1
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-#define TWBR_val ((((F_CPU / F_SCL) / Prescaler) - 16 ) / 2)
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+#define TWBR_val ((((F_CPU / F_SCL) / Prescaler) - 16) / 2)
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-void i2c_init(void)
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-{
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- TWSR = 0; /* no prescaler */
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+void i2c_init(void) {
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+ TWSR = 0; /* no prescaler */
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TWBR = (uint8_t)TWBR_val;
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}
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-i2c_status_t i2c_start(uint8_t address, uint16_t timeout)
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-{
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+i2c_status_t i2c_start(uint8_t address, uint16_t timeout) {
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// reset TWI control register
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TWCR = 0;
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// transmit START condition
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- TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
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+ TWCR = (1 << TWINT) | (1 << TWSTA) | (1 << TWEN);
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uint16_t timeout_timer = timer_read();
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- while( !(TWCR & (1<<TWINT)) ) {
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+ while (!(TWCR & (1 << TWINT))) {
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if ((timeout != I2C_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) {
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return I2C_STATUS_TIMEOUT;
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}
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}
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// check if the start condition was successfully transmitted
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- if(((TW_STATUS & 0xF8) != TW_START) && ((TW_STATUS & 0xF8) != TW_REP_START)){ return I2C_STATUS_ERROR; }
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+ if (((TW_STATUS & 0xF8) != TW_START) && ((TW_STATUS & 0xF8) != TW_REP_START)) {
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+ return I2C_STATUS_ERROR;
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+ }
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// load slave address into data register
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TWDR = address;
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// start transmission of address
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- TWCR = (1<<TWINT) | (1<<TWEN);
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+ TWCR = (1 << TWINT) | (1 << TWEN);
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timeout_timer = timer_read();
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- while( !(TWCR & (1<<TWINT)) ) {
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+ while (!(TWCR & (1 << TWINT))) {
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if ((timeout != I2C_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) {
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return I2C_STATUS_TIMEOUT;
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}
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@@ -51,38 +52,39 @@ i2c_status_t i2c_start(uint8_t address, uint16_t timeout)
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// check if the device has acknowledged the READ / WRITE mode
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uint8_t twst = TW_STATUS & 0xF8;
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- if ( (twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK) ) return I2C_STATUS_ERROR;
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+ if ((twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK)) {
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+ return I2C_STATUS_ERROR;
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+ }
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return I2C_STATUS_SUCCESS;
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}
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-i2c_status_t i2c_write(uint8_t data, uint16_t timeout)
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-{
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+i2c_status_t i2c_write(uint8_t data, uint16_t timeout) {
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// load data into data register
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TWDR = data;
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// start transmission of data
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- TWCR = (1<<TWINT) | (1<<TWEN);
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+ TWCR = (1 << TWINT) | (1 << TWEN);
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uint16_t timeout_timer = timer_read();
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- while( !(TWCR & (1<<TWINT)) ) {
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+ while (!(TWCR & (1 << TWINT))) {
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if ((timeout != I2C_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) {
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return I2C_STATUS_TIMEOUT;
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}
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}
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- if( (TW_STATUS & 0xF8) != TW_MT_DATA_ACK ){ return I2C_STATUS_ERROR; }
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+ if ((TW_STATUS & 0xF8) != TW_MT_DATA_ACK) {
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+ return I2C_STATUS_ERROR;
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+ }
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return I2C_STATUS_SUCCESS;
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}
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-int16_t i2c_read_ack(uint16_t timeout)
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-{
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-
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+int16_t i2c_read_ack(uint16_t timeout) {
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// start TWI module and acknowledge data after reception
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- TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA);
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+ TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWEA);
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uint16_t timeout_timer = timer_read();
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- while( !(TWCR & (1<<TWINT)) ) {
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+ while (!(TWCR & (1 << TWINT))) {
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if ((timeout != I2C_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) {
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return I2C_STATUS_TIMEOUT;
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}
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@@ -92,14 +94,12 @@ int16_t i2c_read_ack(uint16_t timeout)
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return TWDR;
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}
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-int16_t i2c_read_nack(uint16_t timeout)
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-{
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-
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+int16_t i2c_read_nack(uint16_t timeout) {
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// start receiving without acknowledging reception
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- TWCR = (1<<TWINT) | (1<<TWEN);
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+ TWCR = (1 << TWINT) | (1 << TWEN);
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uint16_t timeout_timer = timer_read();
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- while( !(TWCR & (1<<TWINT)) ) {
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+ while (!(TWCR & (1 << TWINT))) {
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if ((timeout != I2C_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) {
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return I2C_STATUS_TIMEOUT;
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}
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@@ -109,115 +109,89 @@ int16_t i2c_read_nack(uint16_t timeout)
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return TWDR;
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}
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-i2c_status_t i2c_transmit(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout)
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-{
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+i2c_status_t i2c_transmit(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout) {
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i2c_status_t status = i2c_start(address | I2C_WRITE, timeout);
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- if (status) return status;
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- for (uint16_t i = 0; i < length; i++) {
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+ for (uint16_t i = 0; i < length && status >= 0; i++) {
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status = i2c_write(data[i], timeout);
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- if (status) return status;
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}
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- status = i2c_stop(timeout);
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- if (status) return status;
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+ i2c_stop();
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- return I2C_STATUS_SUCCESS;
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+ return status;
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}
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-i2c_status_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout)
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-{
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+i2c_status_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout) {
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i2c_status_t status = i2c_start(address | I2C_READ, timeout);
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- if (status) return status;
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- for (uint16_t i = 0; i < (length-1); i++) {
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+ for (uint16_t i = 0; i < (length - 1) && status >= 0; i++) {
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status = i2c_read_ack(timeout);
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if (status >= 0) {
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data[i] = status;
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- } else {
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- return status;
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}
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}
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- status = i2c_read_nack(timeout);
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- if (status >= 0 ) {
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- data[(length-1)] = status;
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- } else {
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- return status;
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+ if (status >= 0) {
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+ status = i2c_read_nack(timeout);
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+ if (status >= 0) {
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+ data[(length - 1)] = status;
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+ }
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}
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- status = i2c_stop(timeout);
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- if (status) return status;
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+ i2c_stop();
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- return I2C_STATUS_SUCCESS;
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+ return status;
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}
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-i2c_status_t i2c_writeReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout)
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-{
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+i2c_status_t i2c_writeReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout) {
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i2c_status_t status = i2c_start(devaddr | 0x00, timeout);
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- if (status) return status;
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-
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- status = i2c_write(regaddr, timeout);
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- if (status) return status;
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+ if (status >= 0) {
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+ status = i2c_write(regaddr, timeout);
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- for (uint16_t i = 0; i < length; i++) {
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- status = i2c_write(data[i], timeout);
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- if (status) return status;
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+ for (uint16_t i = 0; i < length && status >= 0; i++) {
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+ status = i2c_write(data[i], timeout);
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+ }
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}
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- status = i2c_stop(timeout);
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- if (status) return status;
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+ i2c_stop();
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- return I2C_STATUS_SUCCESS;
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+ return status;
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}
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-i2c_status_t i2c_readReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout)
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-{
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+i2c_status_t i2c_readReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout) {
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i2c_status_t status = i2c_start(devaddr, timeout);
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- if (status) return status;
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+ if (status < 0) {
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+ goto error;
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+ }
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status = i2c_write(regaddr, timeout);
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- if (status) return status;
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-
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- status = i2c_stop(timeout);
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- if (status) return status;
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+ if (status < 0) {
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+ goto error;
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+ }
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status = i2c_start(devaddr | 0x01, timeout);
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- if (status) return status;
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- for (uint16_t i = 0; i < (length-1); i++) {
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+ for (uint16_t i = 0; i < (length - 1) && status >= 0; i++) {
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status = i2c_read_ack(timeout);
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if (status >= 0) {
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data[i] = status;
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- } else {
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- return status;
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}
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}
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- status = i2c_read_nack(timeout);
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- if (status >= 0 ) {
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- data[(length-1)] = status;
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- } else {
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- return status;
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+ if (status >= 0) {
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+ status = i2c_read_nack(timeout);
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+ if (status >= 0) {
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+ data[(length - 1)] = status;
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+ }
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}
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- status = i2c_stop(timeout);
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- if (status) return status;
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+error:
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+ i2c_stop();
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- return I2C_STATUS_SUCCESS;
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+ return status;
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}
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-i2c_status_t i2c_stop(uint16_t timeout)
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-{
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+void i2c_stop(void) {
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// transmit STOP condition
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- TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
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-
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- uint16_t timeout_timer = timer_read();
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- while(TWCR & (1<<TWSTO)) {
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- if ((timeout != I2C_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) {
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- return I2C_STATUS_TIMEOUT;
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- }
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- }
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-
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- return I2C_STATUS_SUCCESS;
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+ TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWSTO);
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}
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