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i2c.c
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/
i2c.c
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//
// i2c.c
// i2c
//
// Created by Michael Köhler on 09.10.17.
//
//
#include "i2c.h"
#if defined (__AVR_ATmega328__) || defined(__AVR_ATmega328P__) || defined(__AVR_ATmega168P__) || defined(__AVR_ATmega168PA__) || defined(__AVR_ATmega88P__) || defined(__AVR_ATmega48P__) || defined(__AVR_ATmega1284P__) || defined (__AVR_ATmega324A__) || defined (__AVR_ATmega324P__) || defined (__AVR_ATmega324PA__) || defined (__AVR_ATmega644__) || defined (__AVR_ATmega644A__) || defined (__AVR_ATmega644P__) || defined (__AVR_ATmega644PA__) || defined (__AVR_ATmega1284P__)
#if PSC_I2C != 1 && PSC_I2C != 4 && PSC_I2C != 16 && PSC_I2C != 64
#error "Wrong prescaler for TWI !"
#elif SET_TWBR < 0 || SET_TWBR > 255
#error "TWBR out of range, change PSC_I2C or F_I2C !"
#endif
uint8_t I2C_ErrorCode;
/**********************************************
Public Function: i2c_init
Purpose: Initialise TWI/I2C interface
Input Parameter: none
Return Value: none
**********************************************/
void i2c_init(void){
// set clock
switch (PSC_I2C) {
case 4:
TWSR = 0x1;
break;
case 16:
TWSR = 0x2;
break;
case 64:
TWSR = 0x3;
break;
default:
TWSR = 0x00;
break;
}
TWBR = (uint8_t)SET_TWBR;
// enable
TWCR = (1 << TWEN);
}
/**********************************************
Public Function: i2c_start
Purpose: Start TWI/I2C interface
Input Parameter:
- uint8_t i2c_addr: Adress of reciever
Return Value: none
**********************************************/
void i2c_start(uint8_t i2c_addr){
// i2c start
TWCR = (1 << TWINT)|(1 << TWSTA)|(1 << TWEN);
uint16_t timeout = F_CPU/F_I2C*2.0;
while((TWCR & (1 << TWINT)) == 0 &&
timeout !=0){
timeout--;
if(timeout == 0){
I2C_ErrorCode |= (1 << I2C_START);
return;
}
};
// send adress
TWDR = i2c_addr;
TWCR = (1 << TWINT)|( 1 << TWEN);
timeout = F_CPU/F_I2C*2.0;
while((TWCR & (1 << TWINT)) == 0 &&
timeout !=0){
timeout--;
if(timeout == 0){
I2C_ErrorCode |= (1 << I2C_SENDADRESS);
return;
}
};
}
/**********************************************
Public Function: i2c_stop
Purpose: Stop TWI/I2C interface
Input Parameter: none
Return Value: none
**********************************************/
void i2c_stop(void){
// i2c stop
TWCR = (1 << TWINT)|(1 << TWSTO)|(1 << TWEN);
}
/**********************************************
Public Function: i2c_byte
Purpose: Send byte at TWI/I2C interface
Input Parameter:
- uint8_t byte: Byte to send to reciever
Return Value: none
**********************************************/
void i2c_byte(uint8_t byte){
TWDR = byte;
TWCR = (1 << TWINT)|( 1 << TWEN);
uint16_t timeout = F_CPU/F_I2C*2.0;
while((TWCR & (1 << TWINT)) == 0 &&
timeout !=0){
timeout--;
if(timeout == 0){
I2C_ErrorCode |= (1 << I2C_BYTE);
return;
}
};
}
/**********************************************
Public Function: i2c_readAck
Purpose: read acknowledge from TWI/I2C Interface
Input Parameter: none
Return Value: uint8_t
- TWDR: recieved value at TWI/I2C-Interface, 0 at timeout
- 0: Error at read
**********************************************/
uint8_t i2c_readAck(void){
TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWEA);
uint16_t timeout = F_CPU/F_I2C*2.0;
while((TWCR & (1 << TWINT)) == 0 &&
timeout !=0){
timeout--;
if(timeout == 0){
I2C_ErrorCode |= (1 << I2C_READACK);
return 0;
}
};
return TWDR;
}
/**********************************************
Public Function: i2c_readNAck
Purpose: read non-acknowledge from TWI/I2C Interface
Input Parameter: none
Return Value: uint8_t
- TWDR: recieved value at TWI/I2C-Interface
- 0: Error at read
**********************************************/
uint8_t i2c_readNAck(void){
TWCR = (1<<TWINT)|(1<<TWEN);
uint16_t timeout = F_CPU/F_I2C*2.0;
while((TWCR & (1 << TWINT)) == 0 &&
timeout !=0){
timeout--;
if(timeout == 0){
I2C_ErrorCode |= (1 << I2C_READNACK);
return 0;
}
};
return TWDR;
}
#else
#error "Micorcontroller not supported now!"
#endif