44 lines
1.1 KiB
C
44 lines
1.1 KiB
C
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#include <avr/io.h>
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#include <util/delay.h>
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#include "i2c.h"
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void initI2C() {
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// Set the prescaler to 1
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TWSR &= ~(1 << TWPS0);
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TWSR &= ~(1 << TWPS1);
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// Set the bit rate to 100kHz
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TWBR = ((F_CPU / 100000) - 16) / 2;
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}
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void I2C_start() {
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// Send the start condition
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TWCR = (1 << TWINT) | (1 << TWSTA) | (1 << TWEN);
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// Wait for the start condition to be sent
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while (!(TWCR & (1 << TWINT)))
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;
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}
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void I2C_stop() {
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// Send the stop condition
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TWCR = (1 << TWINT) | (1 << TWSTO) | (1 << TWEN);
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// Wait for the stop condition to be sent
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while (TWCR & (1 << TWSTO));
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}
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void I2C_write(uint8_t data) {
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// Load the data into the data register
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TWDR = data;
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// Start transmission of data
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TWCR = (1 << TWINT) | (1 << TWEN);
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// Wait for the data to be sent
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while (!(TWCR & (1 << TWINT)));
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}
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uint8_t I2C_read(uint8_t ack) {
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// Enable TWI, generate ACK (if ack = 1) and clear TWI interrupt flag
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TWCR = (1 << TWINT) | (1 << TWEN) | (ack << TWEA);
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// Wait until TWI finish its current job (read operation)
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while (!(TWCR & (1 << TWINT)));
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// Return received data
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return TWDR;
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}
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