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66 lines
1.5 KiB
C
66 lines
1.5 KiB
C
7 years ago
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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_ATmega328P__) || defined(__AVR_ATmega168P__) || defined(__AVR_ATmega168PA__) || defined(__AVR_ATmega88P__) || defined(__AVR_ATmega48P__) || defined(__AVR_ATmega1284P__)
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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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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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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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while((TWCR & (1 << TWINT)) == 0);
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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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while((TWCR & (1 << TWINT)) == 0);
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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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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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while((TWCR & (1 << TWINT)) == 0);
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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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while ((TWCR & (1<<TWINT)) == 0);
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return TWDR;
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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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while ((TWCR & (1<<TWINT)) == 0);
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return TWDR;
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}
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#endif
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