#include "i2c_master.h"
#include "timer.h"
+#include "wait.h"
-#define F_SCL 400000UL // SCL frequency
+#ifndef F_SCL
+# define F_SCL 400000UL // SCL frequency
+#endif
#define Prescaler 1
-#define TWBR_val ((((F_CPU / F_SCL) / Prescaler) - 16 ) / 2)
+#define TWBR_val ((((F_CPU / F_SCL) / Prescaler) - 16) / 2)
-void i2c_init(void)
-{
- TWSR = 0; /* no prescaler */
- TWBR = (uint8_t)TWBR_val;
+void i2c_init(void) {
+ TWSR = 0; /* no prescaler */
+ TWBR = (uint8_t)TWBR_val;
+
+ #ifdef __AVR_ATmega32A__
+ // set pull-up resistors on I2C bus pins
+ PORTC |= 0b11;
+
+ // enable TWI (two-wire interface)
+ TWCR |= (1 << TWEN);
+
+ // enable TWI interrupt and slave address ACK
+ TWCR |= (1 << TWIE);
+ TWCR |= (1 << TWEA);
+ #endif
}
-i2c_status_t i2c_start(uint8_t address, uint16_t timeout)
-{
- // reset TWI control register
- TWCR = 0;
- // transmit START condition
- TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
+i2c_status_t i2c_start(uint8_t address, uint16_t timeout) {
+ // reset TWI control register
+ TWCR = 0;
+ // transmit START condition
+ TWCR = (1 << TWINT) | (1 << TWSTA) | (1 << TWEN);
uint16_t timeout_timer = timer_read();
- while( !(TWCR & (1<<TWINT)) ) {
+ while (!(TWCR & (1 << TWINT))) {
if ((timeout != I2C_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) {
return I2C_STATUS_TIMEOUT;
}
}
- // check if the start condition was successfully transmitted
- if(((TW_STATUS & 0xF8) != TW_START) && ((TW_STATUS & 0xF8) != TW_REP_START)){ return I2C_STATUS_ERROR; }
+ // check if the start condition was successfully transmitted
+ if (((TW_STATUS & 0xF8) != TW_START) && ((TW_STATUS & 0xF8) != TW_REP_START)) {
+ return I2C_STATUS_ERROR;
+ }
- // load slave address into data register
- TWDR = address;
- // start transmission of address
- TWCR = (1<<TWINT) | (1<<TWEN);
+ // load slave address into data register
+ TWDR = address;
+ // start transmission of address
+ TWCR = (1 << TWINT) | (1 << TWEN);
timeout_timer = timer_read();
- while( !(TWCR & (1<<TWINT)) ) {
+ while (!(TWCR & (1 << TWINT))) {
if ((timeout != I2C_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) {
return I2C_STATUS_TIMEOUT;
}
}
- // check if the device has acknowledged the READ / WRITE mode
- uint8_t twst = TW_STATUS & 0xF8;
- if ( (twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK) ) return I2C_STATUS_ERROR;
+ // check if the device has acknowledged the READ / WRITE mode
+ uint8_t twst = TW_STATUS & 0xF8;
+ if ((twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK)) {
+ return I2C_STATUS_ERROR;
+ }
- return I2C_STATUS_SUCCESS;
+ return I2C_STATUS_SUCCESS;
}
-i2c_status_t i2c_write(uint8_t data, uint16_t timeout)
-{
- // load data into data register
- TWDR = data;
- // start transmission of data
- TWCR = (1<<TWINT) | (1<<TWEN);
+i2c_status_t i2c_write(uint8_t data, uint16_t timeout) {
+ // load data into data register
+ TWDR = data;
+ // start transmission of data
+ TWCR = (1 << TWINT) | (1 << TWEN);
uint16_t timeout_timer = timer_read();
- while( !(TWCR & (1<<TWINT)) ) {
+ while (!(TWCR & (1 << TWINT))) {
if ((timeout != I2C_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) {
return I2C_STATUS_TIMEOUT;
}
}
- if( (TW_STATUS & 0xF8) != TW_MT_DATA_ACK ){ return I2C_STATUS_ERROR; }
+ if ((TW_STATUS & 0xF8) != TW_MT_DATA_ACK) {
+ return I2C_STATUS_ERROR;
+ }
- return I2C_STATUS_SUCCESS;
+ return I2C_STATUS_SUCCESS;
}
-int16_t i2c_read_ack(uint16_t timeout)
-{
-
- // start TWI module and acknowledge data after reception
- TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA);
+int16_t i2c_read_ack(uint16_t timeout) {
+ // start TWI module and acknowledge data after reception
+ TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWEA);
uint16_t timeout_timer = timer_read();
- while( !(TWCR & (1<<TWINT)) ) {
+ while (!(TWCR & (1 << TWINT))) {
if ((timeout != I2C_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) {
return I2C_STATUS_TIMEOUT;
}
}
- // return received data from TWDR
- return TWDR;
+ // return received data from TWDR
+ return TWDR;
}
-int16_t i2c_read_nack(uint16_t timeout)
-{
-
- // start receiving without acknowledging reception
- TWCR = (1<<TWINT) | (1<<TWEN);
+int16_t i2c_read_nack(uint16_t timeout) {
+ // start receiving without acknowledging reception
+ TWCR = (1 << TWINT) | (1 << TWEN);
uint16_t timeout_timer = timer_read();
- while( !(TWCR & (1<<TWINT)) ) {
+ while (!(TWCR & (1 << TWINT))) {
if ((timeout != I2C_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) {
return I2C_STATUS_TIMEOUT;
}
}
- // return received data from TWDR
- return TWDR;
+ // return received data from TWDR
+ return TWDR;
}
-i2c_status_t i2c_transmit(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout)
-{
+i2c_status_t i2c_transmit(uint8_t address, const uint8_t* data, uint16_t length, uint16_t timeout) {
i2c_status_t status = i2c_start(address | I2C_WRITE, timeout);
- if (status) return status;
- for (uint16_t i = 0; i < length; i++) {
- status = i2c_write(data[i], timeout);
- if (status) return status;
- }
+ for (uint16_t i = 0; i < length && status >= 0; i++) {
+ status = i2c_write(data[i], timeout);
+ }
- status = i2c_stop(timeout);
- if (status) return status;
+ i2c_stop();
- return I2C_STATUS_SUCCESS;
+ return status;
}
-i2c_status_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout)
-{
+i2c_status_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout) {
i2c_status_t status = i2c_start(address | I2C_READ, timeout);
- if (status) return status;
- for (uint16_t i = 0; i < (length-1); i++) {
+ for (uint16_t i = 0; i < (length - 1) && status >= 0; i++) {
status = i2c_read_ack(timeout);
if (status >= 0) {
data[i] = status;
- } else {
- return status;
}
- }
+ }
- status = i2c_read_nack(timeout);
- if (status >= 0 ) {
- data[(length-1)] = status;
- } else {
- return status;
+ if (status >= 0) {
+ status = i2c_read_nack(timeout);
+ if (status >= 0) {
+ data[(length - 1)] = status;
+ }
}
- status = i2c_stop(timeout);
- if (status) return status;
+ i2c_stop();
- return I2C_STATUS_SUCCESS;
+ return (status < 0) ? status : I2C_STATUS_SUCCESS;
}
-i2c_status_t i2c_writeReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout)
-{
+i2c_status_t i2c_writeReg(uint8_t devaddr, uint8_t regaddr, const uint8_t* data, uint16_t length, uint16_t timeout) {
i2c_status_t status = i2c_start(devaddr | 0x00, timeout);
- if (status) return status;
+ if (status >= 0) {
+ status = i2c_write(regaddr, timeout);
- status = i2c_write(regaddr, timeout);
- if (status) return status;
-
- for (uint16_t i = 0; i < length; i++) {
- status = i2c_write(data[i], timeout);
- if (status) return status;
- }
+ for (uint16_t i = 0; i < length && status >= 0; i++) {
+ status = i2c_write(data[i], timeout);
+ }
+ }
- status = i2c_stop(timeout);
- if (status) return status;
+ i2c_stop();
- return I2C_STATUS_SUCCESS;
+ return status;
}
-i2c_status_t i2c_readReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout)
-{
+i2c_status_t i2c_readReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout) {
i2c_status_t status = i2c_start(devaddr, timeout);
- if (status) return status;
+ if (status < 0) {
+ goto error;
+ }
status = i2c_write(regaddr, timeout);
- if (status) return status;
+ if (status < 0) {
+ goto error;
+ }
status = i2c_start(devaddr | 0x01, timeout);
- if (status) return status;
- for (uint16_t i = 0; i < (length-1); i++) {
- status = i2c_read_ack(timeout);
+ for (uint16_t i = 0; i < (length - 1) && status >= 0; i++) {
+ status = i2c_read_ack(timeout);
if (status >= 0) {
data[i] = status;
- } else {
- return status;
}
- }
+ }
- status = i2c_read_nack(timeout);
- if (status >= 0 ) {
- data[(length-1)] = status;
- } else {
- return status;
+ if (status >= 0) {
+ status = i2c_read_nack(timeout);
+ if (status >= 0) {
+ data[(length - 1)] = status;
+ }
}
- status = i2c_stop(timeout);
- if (status) return status;
+error:
+ i2c_stop();
- return I2C_STATUS_SUCCESS;
+ return (status < 0) ? status : I2C_STATUS_SUCCESS;
}
-i2c_status_t i2c_stop(uint16_t timeout)
-{
- // transmit STOP condition
- TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
-
- uint16_t timeout_timer = timer_read();
- while(TWCR & (1<<TWSTO)) {
- if ((timeout != I2C_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) {
- return I2C_STATUS_TIMEOUT;
- }
- }
-
- return I2C_STATUS_SUCCESS;
+void i2c_stop(void) {
+ // transmit STOP condition
+ TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWSTO);
}
projects / qmk_firmware.git / blobdiff