uint8_t twi_sync_mt(uint8_t address, uint8_t *req_data, uint8_t req_len) {
// write start condition
write_start();
WAIT_FOR_BUS();
// write SLA+W
write_slave_address(address, TW_WRITE);
WAIT_FOR_BUS();
if (TW_STATUS != TW_MT_SLA_ACK) {
write_stop();
return TWI_ERROR;
}
// write request data
while (req_len--) {
write_data_byte(*req_data++);
WAIT_FOR_BUS();
if (TW_STATUS != TW_MT_DATA_ACK) {
write_stop();
return TWI_ERROR;
}
}
// write stop condition
write_stop();
while (!(TWCR & (1 << TWSTO)));
return TWI_OK;
}
/// write to a connect I2C slave device
//
/// This function writes n bytes of data to the device with address a
/// that is connected to the I2C bus.
void write( fast_byte a, const byte data[], fast_byte n ) override {
write_start();
write_byte( a << 1 );
for( fast_byte i = 0; i < n; i++ ){
read_ack();
write_byte( data[ i ] );
}
read_ack();
write_stop();
}
/// read from a connected I2C slave device
//
/// This function reads n bytes of data from the device with address a
/// that is connected to the I2C bus.
void read( fast_byte a, byte data[], fast_byte n ) override {
write_start();
write_byte( ( a << 1 ) | 0x01 );
read_ack();
for( fast_byte i = 0; i < n; i++ ){
if( i > 0 ){
write_ack();
}
data[ i ] = read_byte();
}
write_stop();
}
uint8_t twi_sync_mtmr(uint8_t address, uint8_t *req_data, uint8_t req_len, uint8_t *res_data, uint8_t res_len) {
// Master Transmitter
// write start condition
write_start();
WAIT_FOR_BUS();
// write SLA+W
write_slave_address(address, TW_WRITE);
WAIT_FOR_BUS();
if (TW_STATUS != TW_MT_SLA_ACK) {
write_stop();
return TWI_ERROR;
}
// write request data
while (req_len--) {
write_data_byte(*req_data++);
WAIT_FOR_BUS();
if (TW_STATUS != TW_MT_DATA_ACK) {
write_stop();
return TWI_ERROR;
}
}
// Master Receiver
// write repeated start
write_start();
WAIT_FOR_BUS();
if (TW_STATUS != TW_REP_START) {
write_stop();
return TWI_ERROR;
}
// write SLA+R
write_slave_address(address, TW_READ);
WAIT_FOR_BUS();
if (TW_STATUS != TW_MR_SLA_ACK) {
write_stop();
return TWI_ERROR;
}
// read data
while (res_len > 1) {
read_data_byte(res_data++, 1);
WAIT_FOR_BUS();
if (TW_STATUS != TW_MR_DATA_ACK) {
write_stop();
return TWI_ERROR;
}
res_len--;
}
read_data_byte(res_data++, 0);
WAIT_FOR_BUS();
if (TW_STATUS != TW_MR_DATA_NACK) {
write_stop();
return TWI_ERROR;
}
// write stop condition
write_stop();
while (!(TWCR & (1 << TWSTO)));
return TWI_OK;
}
