unsigned char i2c_read_bit(void) {
unsigned char bit;
read_SDA();
I2C_delay();
while (read_SCL() == 0); // Clock stretching
bit = read_SDA();
I2C_delay();
clear_SCL();
I2C_delay();
return bit;
}
void i2c_stop(void) {
// set SDA to 0
clear_SDA();
I2C_delay();
while (read_SCL() == 0); // Clock stretching
I2C_delay();
if (read_SDA() == 0) {
arbitration_lost();
}
I2C_delay();
started = 0;
}
// Read a bit from I2C bus
bool i2c_read_bit(void) {
bool bit;
// Let the slave drive data
read_SDA();
I2C_delay();
while (read_SCL() == 0) { // Clock stretching
// You should add timeout to this loop
}
// SCL is high, now data is valid
bit = read_SDA();
I2C_delay();
clear_SCL();
return bit;
}
void i2c_write_bit(unsigned char bit) {
if (bit) {
read_SDA();
} else {
clear_SDA();
}
I2C_delay();
while (read_SCL() == 0); // Clock stretching
if (bit && read_SDA() == 0) {
//Houve problema de comunicação
}
I2C_delay();
clear_SCL();
I2C_delay();
}
void i2c_stop_cond(void){
// set SDA to 0
clear_SDA();
I2C_delay();
// Clock stretching
while (read_SCL() == 0) {
// add timeout to this loop.
}
// Stop bit setup time, minimum 4us
I2C_delay();
// SCL is high, set SDA from 0 to 1
if (read_SDA() == 0) {
arbitration_lost();
}
I2C_delay();
started = false;
}
// Write a bit to I2C bus
void i2c_write_bit(bool bit) {
if (bit) {
read_SDA();
} else {
clear_SDA();
}
I2C_delay();
while (read_SCL() == 0) { // Clock stretching
// You should add timeout to this loop
}
// SCL is high, now data is valid
// If SDA is high, check that nobody else is driving SDA
if (bit && read_SDA() == 0) {
arbitration_lost();
}
I2C_delay();
clear_SCL();
}
void i2c_start(void) {
//se já estiver iniciado, prepara para reenviar o bit de start
if (started) {
read_SDA();
I2C_delay();
while (read_SCL() == 0); // Clock stretching
// Repeated start setup time, minimum 4.7us
I2C_delay();
}
if (read_SDA() == 0) {
//Houve problema de comunicação
}
// SCL is high, set SDA from 1 to 0.
clear_SDA();
I2C_delay();
clear_SCL();
started = 1;
}
void i2c_start_cond(void) {
if (started) { // if started, do a restart cond
// set SDA to 1
read_SDA();
I2C_delay();
while (read_SCL() == 0) { // Clock stretching
// You should add timeout to this loop
}
// Repeated start setup time, minimum 4.7us
I2C_delay();
}
if (read_SDA() == 0) {
arbitration_lost();
}
// SCL is high, set SDA from 1 to 0.
clear_SDA();
I2C_delay();
clear_SCL();
started = true;
}