301 lines
8.3 KiB
C
301 lines
8.3 KiB
C
/* Copyright (C) 2019 Elia Ritterbusch
|
|
+
|
|
* This program is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <https://www.gnu.org/licenses/>.
|
|
*/
|
|
/* Library made by: g4lvanix
|
|
* GitHub repository: https://github.com/g4lvanix/I2C-master-lib
|
|
*/
|
|
|
|
#include <avr/io.h>
|
|
#include <util/twi.h>
|
|
|
|
#include "i2c_master.h"
|
|
#include "timer.h"
|
|
#include "wait.h"
|
|
|
|
#ifndef F_SCL
|
|
# define F_SCL 400000UL // SCL frequency
|
|
#endif
|
|
|
|
#ifndef I2C_START_RETRY_COUNT
|
|
# define I2C_START_RETRY_COUNT 20
|
|
#endif // I2C_START_RETRY_COUNT
|
|
|
|
#define I2C_ACTION_READ 0x01
|
|
#define I2C_ACTION_WRITE 0x00
|
|
|
|
#define TWBR_val (((F_CPU / F_SCL) - 16) / 2)
|
|
|
|
#define MAX(X, Y) ((X) > (Y) ? (X) : (Y))
|
|
|
|
void i2c_init(void) {
|
|
TWSR = 0; /* no prescaler */
|
|
TWBR = (uint8_t)TWBR_val;
|
|
|
|
#ifdef __AVR_ATmega32A__
|
|
// set pull-up resistors on I2C bus pins
|
|
PORTC |= 0b11;
|
|
|
|
// enable TWI (two-wire interface)
|
|
TWCR |= (1 << TWEN);
|
|
|
|
// enable TWI interrupt and slave address ACK
|
|
TWCR |= (1 << TWIE);
|
|
TWCR |= (1 << TWEA);
|
|
#endif
|
|
}
|
|
|
|
static i2c_status_t i2c_start_impl(uint8_t address, uint16_t timeout) {
|
|
// reset TWI control register
|
|
TWCR = 0;
|
|
// transmit START condition
|
|
TWCR = (1 << TWINT) | (1 << TWSTA) | (1 << TWEN);
|
|
|
|
uint16_t timeout_timer = timer_read();
|
|
while (!(TWCR & (1 << TWINT))) {
|
|
if ((timeout != I2C_TIMEOUT_INFINITE) && (timer_elapsed(timeout_timer) > timeout)) {
|
|
return I2C_STATUS_TIMEOUT;
|
|
}
|
|
}
|
|
|
|
// check if the start condition was successfully transmitted
|
|
if (((TW_STATUS & 0xF8) != TW_START) && ((TW_STATUS & 0xF8) != TW_REP_START)) {
|
|
return I2C_STATUS_ERROR;
|
|
}
|
|
|
|
// load slave address into data register
|
|
TWDR = address;
|
|
// start transmission of address
|
|
TWCR = (1 << TWINT) | (1 << TWEN);
|
|
|
|
timeout_timer = timer_read();
|
|
while (!(TWCR & (1 << TWINT))) {
|
|
if ((timeout != I2C_TIMEOUT_INFINITE) && (timer_elapsed(timeout_timer) > timeout)) {
|
|
return I2C_STATUS_TIMEOUT;
|
|
}
|
|
}
|
|
|
|
// check if the device has acknowledged the READ / WRITE mode
|
|
uint8_t twst = TW_STATUS & 0xF8;
|
|
if ((twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK)) {
|
|
return I2C_STATUS_ERROR;
|
|
}
|
|
|
|
return I2C_STATUS_SUCCESS;
|
|
}
|
|
|
|
i2c_status_t i2c_start(uint8_t address, uint16_t timeout) {
|
|
// Retry i2c_start_impl a bunch times in case the remote side has interrupts disabled.
|
|
uint16_t timeout_timer = timer_read();
|
|
uint16_t time_slice = MAX(1, (timeout == (I2C_TIMEOUT_INFINITE)) ? 5 : (timeout / (I2C_START_RETRY_COUNT))); // if it's infinite, wait 1ms between attempts, otherwise split up the entire timeout into the number of retries
|
|
i2c_status_t status;
|
|
do {
|
|
status = i2c_start_impl(address, time_slice);
|
|
} while ((status < 0) && ((timeout == I2C_TIMEOUT_INFINITE) || (timer_elapsed(timeout_timer) <= timeout)));
|
|
return status;
|
|
}
|
|
|
|
i2c_status_t i2c_write(uint8_t data, uint16_t timeout) {
|
|
// load data into data register
|
|
TWDR = data;
|
|
// start transmission of data
|
|
TWCR = (1 << TWINT) | (1 << TWEN);
|
|
|
|
uint16_t timeout_timer = timer_read();
|
|
while (!(TWCR & (1 << TWINT))) {
|
|
if ((timeout != I2C_TIMEOUT_INFINITE) && (timer_elapsed(timeout_timer) > timeout)) {
|
|
return I2C_STATUS_TIMEOUT;
|
|
}
|
|
}
|
|
|
|
if ((TW_STATUS & 0xF8) != TW_MT_DATA_ACK) {
|
|
return I2C_STATUS_ERROR;
|
|
}
|
|
|
|
return I2C_STATUS_SUCCESS;
|
|
}
|
|
|
|
int16_t i2c_read_ack(uint16_t timeout) {
|
|
// start TWI module and acknowledge data after reception
|
|
TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWEA);
|
|
|
|
uint16_t timeout_timer = timer_read();
|
|
while (!(TWCR & (1 << TWINT))) {
|
|
if ((timeout != I2C_TIMEOUT_INFINITE) && (timer_elapsed(timeout_timer) > timeout)) {
|
|
return I2C_STATUS_TIMEOUT;
|
|
}
|
|
}
|
|
|
|
// return received data from TWDR
|
|
return TWDR;
|
|
}
|
|
|
|
int16_t i2c_read_nack(uint16_t timeout) {
|
|
// start receiving without acknowledging reception
|
|
TWCR = (1 << TWINT) | (1 << TWEN);
|
|
|
|
uint16_t timeout_timer = timer_read();
|
|
while (!(TWCR & (1 << TWINT))) {
|
|
if ((timeout != I2C_TIMEOUT_INFINITE) && (timer_elapsed(timeout_timer) > timeout)) {
|
|
return I2C_STATUS_TIMEOUT;
|
|
}
|
|
}
|
|
|
|
// return received data from TWDR
|
|
return TWDR;
|
|
}
|
|
|
|
i2c_status_t i2c_transmit(uint8_t address, const uint8_t* data, uint16_t length, uint16_t timeout) {
|
|
i2c_status_t status = i2c_start(address | I2C_ACTION_WRITE, timeout);
|
|
|
|
for (uint16_t i = 0; i < length && status >= 0; i++) {
|
|
status = i2c_write(data[i], timeout);
|
|
}
|
|
|
|
i2c_stop();
|
|
|
|
return status;
|
|
}
|
|
|
|
i2c_status_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout) {
|
|
i2c_status_t status = i2c_start(address | I2C_ACTION_READ, timeout);
|
|
|
|
for (uint16_t i = 0; i < (length - 1) && status >= 0; i++) {
|
|
status = i2c_read_ack(timeout);
|
|
if (status >= 0) {
|
|
data[i] = status;
|
|
}
|
|
}
|
|
|
|
if (status >= 0) {
|
|
status = i2c_read_nack(timeout);
|
|
if (status >= 0) {
|
|
data[(length - 1)] = status;
|
|
}
|
|
}
|
|
|
|
i2c_stop();
|
|
|
|
return (status < 0) ? status : I2C_STATUS_SUCCESS;
|
|
}
|
|
|
|
i2c_status_t i2c_writeReg(uint8_t devaddr, uint8_t regaddr, const uint8_t* data, uint16_t length, uint16_t timeout) {
|
|
i2c_status_t status = i2c_start(devaddr | 0x00, timeout);
|
|
if (status >= 0) {
|
|
status = i2c_write(regaddr, timeout);
|
|
|
|
for (uint16_t i = 0; i < length && status >= 0; i++) {
|
|
status = i2c_write(data[i], timeout);
|
|
}
|
|
}
|
|
|
|
i2c_stop();
|
|
|
|
return status;
|
|
}
|
|
|
|
i2c_status_t i2c_writeReg16(uint8_t devaddr, uint16_t regaddr, const uint8_t* data, uint16_t length, uint16_t timeout) {
|
|
i2c_status_t status = i2c_start(devaddr | 0x00, timeout);
|
|
if (status >= 0) {
|
|
status = i2c_write(regaddr >> 8, timeout);
|
|
|
|
if (status >= 0) {
|
|
status = i2c_write(regaddr & 0xFF, timeout);
|
|
|
|
for (uint16_t i = 0; i < length && status >= 0; i++) {
|
|
status = i2c_write(data[i], timeout);
|
|
}
|
|
}
|
|
}
|
|
|
|
i2c_stop();
|
|
|
|
return status;
|
|
}
|
|
|
|
i2c_status_t i2c_readReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout) {
|
|
i2c_status_t status = i2c_start(devaddr, timeout);
|
|
if (status < 0) {
|
|
goto error;
|
|
}
|
|
|
|
status = i2c_write(regaddr, timeout);
|
|
if (status < 0) {
|
|
goto error;
|
|
}
|
|
|
|
status = i2c_start(devaddr | 0x01, timeout);
|
|
|
|
for (uint16_t i = 0; i < (length - 1) && status >= 0; i++) {
|
|
status = i2c_read_ack(timeout);
|
|
if (status >= 0) {
|
|
data[i] = status;
|
|
}
|
|
}
|
|
|
|
if (status >= 0) {
|
|
status = i2c_read_nack(timeout);
|
|
if (status >= 0) {
|
|
data[(length - 1)] = status;
|
|
}
|
|
}
|
|
|
|
error:
|
|
i2c_stop();
|
|
|
|
return (status < 0) ? status : I2C_STATUS_SUCCESS;
|
|
}
|
|
|
|
i2c_status_t i2c_readReg16(uint8_t devaddr, uint16_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout) {
|
|
i2c_status_t status = i2c_start(devaddr, timeout);
|
|
if (status < 0) {
|
|
goto error;
|
|
}
|
|
|
|
status = i2c_write(regaddr >> 8, timeout);
|
|
if (status < 0) {
|
|
goto error;
|
|
}
|
|
status = i2c_write(regaddr & 0xFF, timeout);
|
|
if (status < 0) {
|
|
goto error;
|
|
}
|
|
|
|
status = i2c_start(devaddr | 0x01, timeout);
|
|
|
|
for (uint16_t i = 0; i < (length - 1) && status >= 0; i++) {
|
|
status = i2c_read_ack(timeout);
|
|
if (status >= 0) {
|
|
data[i] = status;
|
|
}
|
|
}
|
|
|
|
if (status >= 0) {
|
|
status = i2c_read_nack(timeout);
|
|
if (status >= 0) {
|
|
data[(length - 1)] = status;
|
|
}
|
|
}
|
|
|
|
error:
|
|
i2c_stop();
|
|
|
|
return (status < 0) ? status : I2C_STATUS_SUCCESS;
|
|
}
|
|
|
|
void i2c_stop(void) {
|
|
// transmit STOP condition
|
|
TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWSTO);
|
|
}
|