diff options
Diffstat (limited to 'drivers/avr/i2c_master.c')
| -rwxr-xr-x | drivers/avr/i2c_master.c | 213 |
1 files changed, 141 insertions, 72 deletions
diff --git a/drivers/avr/i2c_master.c b/drivers/avr/i2c_master.c index f4a4bb7b0b..4e76e2e7c6 100755 --- a/drivers/avr/i2c_master.c +++ b/drivers/avr/i2c_master.c @@ -6,6 +6,7 @@ #include <util/twi.h> #include "i2c_master.h" +#include "timer.h" #define F_SCL 400000UL // SCL frequency #define Prescaler 1 @@ -13,137 +14,205 @@ void i2c_init(void) { + TWSR = 0; /* no prescaler */ TWBR = (uint8_t)TWBR_val; } -uint8_t i2c_start(uint8_t address) +i2c_status_t i2c_start(uint8_t address, uint16_t timeout) { // reset TWI control register TWCR = 0; - // transmit START condition + // transmit START condition TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN); - // wait for end of transmission - while( !(TWCR & (1<<TWINT)) ); - + + uint16_t timeout_timer = timer_read(); + 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((TWSR & 0xF8) != TW_START){ return 1; } - + 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); - // wait for end of transmission - while( !(TWCR & (1<<TWINT)) ); - + + timeout_timer = timer_read(); + 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 1; - - return 0; + if ( (twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK) ) return I2C_STATUS_ERROR; + + return I2C_STATUS_SUCCESS; } -uint8_t i2c_write(uint8_t data) +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); - // wait for end of transmission - while( !(TWCR & (1<<TWINT)) ); - - if( (TWSR & 0xF8) != TW_MT_DATA_ACK ){ return 1; } - - return 0; + + uint16_t timeout_timer = timer_read(); + 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; } + + return I2C_STATUS_SUCCESS; } -uint8_t i2c_read_ack(void) +int16_t i2c_read_ack(uint16_t timeout) { - + // start TWI module and acknowledge data after reception - TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA); - // wait for end of transmission - while( !(TWCR & (1<<TWINT)) ); + TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA); + + uint16_t timeout_timer = timer_read(); + 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; } -uint8_t i2c_read_nack(void) +int16_t i2c_read_nack(uint16_t timeout) { - + // start receiving without acknowledging reception TWCR = (1<<TWINT) | (1<<TWEN); - // wait for end of transmission - while( !(TWCR & (1<<TWINT)) ); + + uint16_t timeout_timer = timer_read(); + 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; } -uint8_t i2c_transmit(uint8_t address, uint8_t* data, uint16_t length) +i2c_status_t i2c_transmit(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout) { - if (i2c_start(address | I2C_WRITE)) return 1; - - for (uint16_t i = 0; i < length; i++) - { - if (i2c_write(data[i])) return 1; + 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; } - - i2c_stop(); - - return 0; + + status = i2c_stop(timeout); + if (status) return status; + + return I2C_STATUS_SUCCESS; } -uint8_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length) +i2c_status_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout) { - if (i2c_start(address | I2C_READ)) return 1; - - for (uint16_t i = 0; i < (length-1); i++) - { - data[i] = i2c_read_ack(); + i2c_status_t status = i2c_start(address | I2C_READ, timeout); + if (status) return status; + + for (uint16_t i = 0; i < (length-1); i++) { + status = i2c_read_ack(timeout); + if (status >= 0) { + data[i] = status; + } else { + return status; + } } - data[(length-1)] = i2c_read_nack(); - - i2c_stop(); - - return 0; + + status = i2c_read_nack(timeout); + if (status >= 0 ) { + data[(length-1)] = status; + } else { + return status; + } + + status = i2c_stop(timeout); + if (status) return status; + + return I2C_STATUS_SUCCESS; } -uint8_t i2c_writeReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length) +i2c_status_t i2c_writeReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout) { - if (i2c_start(devaddr | 0x00)) return 1; + i2c_status_t status = i2c_start(devaddr | 0x00, timeout); + if (status) return status; - i2c_write(regaddr); + status = i2c_write(regaddr, timeout); + if (status) return status; - for (uint16_t i = 0; i < length; i++) - { - if (i2c_write(data[i])) return 1; + for (uint16_t i = 0; i < length; i++) { + status = i2c_write(data[i], timeout); + if (status) return status; } - i2c_stop(); + status = i2c_stop(timeout); + if (status) return status; - return 0; + return I2C_STATUS_SUCCESS; } -uint8_t i2c_readReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length) +i2c_status_t i2c_readReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout) { - if (i2c_start(devaddr)) return 1; - - i2c_write(regaddr); - - if (i2c_start(devaddr | 0x01)) return 1; - - for (uint16_t i = 0; i < (length-1); i++) - { - data[i] = i2c_read_ack(); + i2c_status_t status = i2c_start(devaddr, timeout); + if (status) return status; + + status = i2c_write(regaddr, timeout); + if (status) return status; + + status = i2c_start(devaddr | 0x01, timeout); + if (status) return status; + + for (uint16_t i = 0; i < (length-1); i++) { + status = i2c_read_ack(timeout); + if (status >= 0) { + data[i] = status; + } else { + return status; + } } - data[(length-1)] = i2c_read_nack(); - i2c_stop(); + status = i2c_read_nack(timeout); + if (status >= 0 ) { + data[(length-1)] = status; + } else { + return status; + } - return 0; + status = i2c_stop(timeout); + if (status) return status; + + return I2C_STATUS_SUCCESS; } -void i2c_stop(void) +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; } |