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180 lines
4.2 KiB
C
180 lines
4.2 KiB
C
//
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// i2c.c
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// i2c
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//
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// Created by Michael Köhler on 09.10.17.
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//
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//
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#include "i2c.h"
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#if defined (__AVR_ATmega328__) || defined(__AVR_ATmega328P__) || \
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defined(__AVR_ATmega168P__) || defined(__AVR_ATmega168PA__) || \
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defined(__AVR_ATmega88P__) || \
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defined(__AVR_ATmega8__) || \
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defined(__AVR_ATmega48P__) || \
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defined(__AVR_ATmega1284P__) || \
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defined (__AVR_ATmega324A__) || defined (__AVR_ATmega324P__) || defined (__AVR_ATmega324PA__) || \
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defined (__AVR_ATmega644__) || defined (__AVR_ATmega644A__) || defined (__AVR_ATmega644P__) || defined (__AVR_ATmega644PA__) || \
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defined (__AVR_ATmega1284P__) || \
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defined (__AVR_ATmega2560__)
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#if PSC_I2C != 1 && PSC_I2C != 4 && PSC_I2C != 16 && PSC_I2C != 64
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#error "Wrong prescaler for TWI !"
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#elif SET_TWBR < 0 || SET_TWBR > 255
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#error "TWBR out of range, change PSC_I2C or F_I2C !"
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#endif
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uint8_t I2C_ErrorCode;
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/**********************************************
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Public Function: i2c_init
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Purpose: Initialise TWI/I2C interface
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Input Parameter: none
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Return Value: none
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**********************************************/
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void i2c_init(void){
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// set clock
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switch (PSC_I2C) {
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case 4:
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TWSR = 0x1;
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break;
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case 16:
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TWSR = 0x2;
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break;
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case 64:
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TWSR = 0x3;
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break;
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default:
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TWSR = 0x00;
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break;
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}
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TWBR = (uint8_t)SET_TWBR;
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// enable
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TWCR = (1 << TWEN);
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}
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/**********************************************
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Public Function: i2c_start
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Purpose: Start TWI/I2C interface
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Input Parameter:
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- uint8_t i2c_addr: Adress of reciever
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Return Value: none
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**********************************************/
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void i2c_start(uint8_t i2c_addr){
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// i2c start
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TWCR = (1 << TWINT)|(1 << TWSTA)|(1 << TWEN);
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uint16_t timeout = F_CPU/F_I2C*2.0;
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while((TWCR & (1 << TWINT)) == 0 &&
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timeout !=0){
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timeout--;
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if(timeout == 0){
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I2C_ErrorCode |= (1 << I2C_START);
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return;
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}
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};
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// send adress
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TWDR = i2c_addr;
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TWCR = (1 << TWINT)|( 1 << TWEN);
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timeout = F_CPU/F_I2C*2.0;
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while((TWCR & (1 << TWINT)) == 0 &&
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timeout !=0){
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timeout--;
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if(timeout == 0){
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I2C_ErrorCode |= (1 << I2C_SENDADRESS);
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return;
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}
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};
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}
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/**********************************************
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Public Function: i2c_stop
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Purpose: Stop TWI/I2C interface
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Input Parameter: none
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Return Value: none
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**********************************************/
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void i2c_stop(void){
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// i2c stop
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TWCR = (1 << TWINT)|(1 << TWSTO)|(1 << TWEN);
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}
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/**********************************************
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Public Function: i2c_byte
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Purpose: Send byte at TWI/I2C interface
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Input Parameter:
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- uint8_t byte: Byte to send to reciever
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Return Value: none
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**********************************************/
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void i2c_byte(uint8_t byte){
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TWDR = byte;
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TWCR = (1 << TWINT)|( 1 << TWEN);
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uint16_t timeout = F_CPU/F_I2C*2.0;
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while((TWCR & (1 << TWINT)) == 0 &&
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timeout !=0){
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timeout--;
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if(timeout == 0){
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I2C_ErrorCode |= (1 << I2C_BYTE);
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return;
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}
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};
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}
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/**********************************************
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Public Function: i2c_readAck
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Purpose: read acknowledge from TWI/I2C Interface
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Input Parameter: none
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Return Value: uint8_t
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- TWDR: recieved value at TWI/I2C-Interface, 0 at timeout
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- 0: Error at read
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**********************************************/
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uint8_t i2c_readAck(void){
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TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWEA);
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uint16_t timeout = F_CPU/F_I2C*2.0;
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while((TWCR & (1 << TWINT)) == 0 &&
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timeout !=0){
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timeout--;
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if(timeout == 0){
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I2C_ErrorCode |= (1 << I2C_READACK);
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return 0;
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}
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};
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return TWDR;
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}
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/**********************************************
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Public Function: i2c_readNAck
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Purpose: read non-acknowledge from TWI/I2C Interface
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Input Parameter: none
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Return Value: uint8_t
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- TWDR: recieved value at TWI/I2C-Interface
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- 0: Error at read
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**********************************************/
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uint8_t i2c_readNAck(void){
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TWCR = (1<<TWINT)|(1<<TWEN);
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uint16_t timeout = F_CPU/F_I2C*2.0;
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while((TWCR & (1 << TWINT)) == 0 &&
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timeout !=0){
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timeout--;
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if(timeout == 0){
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I2C_ErrorCode |= (1 << I2C_READNACK);
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return 0;
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}
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};
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return TWDR;
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}
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#else
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#error "Micorcontroller not supported now!"
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#endif
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