uint8_t SHT1x::receiveByte() {
// We should not be interrupted when talking to sensor
taskENTER_CRITICAL();
// Receive data
uint8_t data = 0;
for(int i = 0; i < 8; ++i) {
data <<= 1;
if(sdaRead())
data |= 1;
sclPulse();
delayTimer.uDelay(COM_DELAY);
}
// Acknowledge received data
sdaLo();
delayTimer.uDelay(COM_DELAY);
sclPulse();
sdaHi();
delayTimer.uDelay(COM_DELAY);
taskEXIT_CRITICAL();
return data;
}
/**
* Send byte to sensor
*
* @param data Byte to send
* @return True when successful, false otherwise
*/
bool SHT1x::sendByte(uint8_t data) {
// We should not be interrupted when talking to sensor
taskENTER_CRITICAL();
// Send command data
for(int i = 0; i < 8; ++i) {
if(data & 0b10000000)
sdaHi();
else
sdaLo();
data <<= 1;
delayTimer.uDelay(COM_DELAY);
sclPulse();
}
// Read acknowledge
sdaHi();
delayTimer.mDelay(5);
uint8_t ack = sdaRead();
sclPulse();
taskEXIT_CRITICAL();
return !ack;
}
static void i2cBitTx(uint8_t instance, char bit){
if(bit) sdaHi(instance);
else sdaLo(instance);
i2cDelay(instance);
sclHi(instance);
i2cDelay(instance);
sclLo(instance);
}
static void i2cStop(uint8_t instance){
i2cDelay(instance);
sdaLo(instance);
i2cDelay(instance);
sclHi(instance);
i2cDelay(instance);
sdaHi(instance);
}
static void i2cStart(uint8_t instance){
sdaHi(instance);
sclHi(instance);
i2cDelay(instance);
sdaLo(instance);
i2cDelay(instance);
sclLo(instance);
i2cDelay(instance);
}
void SHT1x::startCommand() {
// Command start sequence
sdaHi();
sclLo();
delayTimer.uDelay(COM_DELAY);
sclHi();
delayTimer.uDelay(COM_DELAY);
sdaLo();
delayTimer.uDelay(COM_DELAY);
sclLo();
delayTimer.uDelay(COM_DELAY);
sclHi();
delayTimer.uDelay(COM_DELAY);
sdaHi();
delayTimer.uDelay(COM_DELAY);
sclLo();
}
