142 lines
3.5 KiB
C
142 lines
3.5 KiB
C
#include "i2c.h"
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#include <util/twi.h>
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void i2c_init()
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{
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// Set SCL and SDA as inputs (automatically done by TWI hardware)
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TWSR = 0; // Prescaler = 1
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TWBR = (uint8_t)((F_CPU / F_SCL - 16) / 2); // Set bitrate register
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TWCR = (1 << TWEN);
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}
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// Start i2c communication
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uint8_t i2c_start(uint8_t address)
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{
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TWCR = (1 << TWSTA) | (1 << TWINT) | (1 << TWEN); // Send START condition
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while (!(TWCR & (1 << TWINT)))
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; // Wait for TWINT flag to be set
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TWDR = address; // Load address into data register
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TWCR = (1 << TWINT) | (1 << TWEN); // Send address
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while (!(TWCR & (1 << TWINT)))
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; // Wait for TWINT flag to be set
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uint8_t status = TWSR & 0xF8;
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if (status != 0x18 && status != 0x40)
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return 1;
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return 0;
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// return (TWSR & 0xF8); // Return the status code (check if ACK
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// received)
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}
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uint8_t write_one_byte(uint8_t device_addr, uint8_t register_addr, uint8_t data)
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{
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return write_n_bytes(device_addr, register_addr, &data, 1);
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}
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uint8_t write_n_bytes(uint8_t device_addr, uint8_t register_addr, uint8_t* data, uint8_t n_bytes)
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{
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I2C_START_WRITE(device_addr);
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i2c_write(register_addr);
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for (uint8_t i = 0; i < n_bytes; i++) {
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i2c_write(data[i]);
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}
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i2c_stop();
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return 0;
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}
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uint8_t read_one_byte_no_err_register(uint8_t device_addr, uint8_t register_addr)
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{
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uint8_t data;
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read_one_byte(device_addr, register_addr, &data);
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return data;
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}
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uint8_t read_one_byte(uint8_t device_addr, uint8_t register_addr, uint8_t* data)
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{
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return read_n_bytes(device_addr, register_addr, data, 1);
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}
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uint8_t read_n_bytes(uint8_t device_addr, uint8_t register_addr, uint8_t* data, uint8_t n_bytes)
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{
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I2C_START_WRITE(device_addr);
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i2c_write(register_addr);
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I2C_START_READ(device_addr);
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for (uint8_t i = 0; i < (n_bytes - 1); i++) {
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data[i] = i2c_read_ack();
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}
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data[n_bytes - 1] = i2c_read_nack();
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i2c_stop();
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return 0;
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}
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uint8_t read_one_byte_16bit_addr_no_err_register(uint8_t device_addr, uint16_t register_addr)
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{
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uint8_t data;
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read_one_byte_16bit_addr(device_addr, register_addr, &data);
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return data;
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}
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uint8_t read_one_byte_16bit_addr(uint8_t device_addr, uint16_t register_addr, uint8_t* data)
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{
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return read_n_bytes_16bit_addr(device_addr, register_addr, data, 1);
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}
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uint8_t
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read_n_bytes_16bit_addr(uint8_t device_addr, uint16_t register_addr, uint8_t* data, uint8_t n_bytes)
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{
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I2C_START_WRITE(device_addr);
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// i2c_write(0xAE);
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i2c_write(register_addr >> 8);
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i2c_write(register_addr & 0xFF);
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I2C_START_READ(device_addr);
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for (uint8_t i = 0; i < (n_bytes - 1); i++) {
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data[i] = i2c_read_ack();
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}
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data[n_bytes - 1] = i2c_read_nack();
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i2c_stop();
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return 0;
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}
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// Stop i2c communication
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void i2c_stop()
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{
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TWCR = (1 << TWSTO) | (1 << TWINT) | (1 << TWEN); // Send STOP condition
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while (!(TWCR & (1 << TWSTO)))
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; // Wait for STOP to complete
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}
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uint8_t i2c_read_ack()
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{
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TWCR = (1 << TWEN) | (1 << TWINT) | (1 << TWEA);
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while (!(TWCR & (1 << TWINT)))
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; // Wait for TWINT flag to be set
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return TWDR;
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}
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uint8_t i2c_write(uint8_t data)
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{
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// Load data into TWDR
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TWDR = data;
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TWCR = (1 << TWEN) | (1 << TWINT);
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while (!(TWCR & (1 << TWINT)))
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; // Wait for TWINT flag set
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if ((TWSR & 0xF8) != TW_MT_DATA_ACK)
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return 1; // Check ACK
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return 0;
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}
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uint8_t i2c_read_nack()
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{
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TWCR = (1 << TWEN) | (1 << TWINT);
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while (!(TWCR & (1 << TWINT)))
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; // Wait for TWINT flag to be set
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return TWDR;
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} |