/**
* Gets the current temperature of the microbit.
* @return the current temperature, in degrees celsius.
*
* Example:
* @code
* uBit.thermometer.getTemperature();
* @endcode
*/
int MicroBitThermometer::getTemperature()
{
if (isSampleNeeded())
updateTemperature();
return temperature;
}
/**
* Updates the temperature sample of this instance of MicroBitThermometer
* only if isSampleNeeded() indicates that an update is required.
*
* This call also will add the thermometer to fiber components to receive
* periodic callbacks.
*
* @return MICROBIT_OK on success.
*/
int MicroBitThermometer::updateSample()
{
if(!(status & MICROBIT_THERMOMETER_ADDED_TO_IDLE))
{
// If we're running under a fiber scheduer, register ourselves for a periodic callback to keep our data up to date.
// Otherwise, we do just do this on demand, when polled through our read() interface.
fiber_add_idle_component(this);
status |= MICROBIT_THERMOMETER_ADDED_TO_IDLE;
}
// check if we need to update our sample...
if(isSampleNeeded())
{
int32_t processorTemperature;
uint8_t sd_enabled;
// For now, we just rely on the nrf senesor to be the most accurate.
// The compass module also has a temperature sensor, and has the lowest power consumption, so will run the cooler...
// ...however it isn't trimmed for accuracy during manufacture, so requires calibration.
sd_softdevice_is_enabled(&sd_enabled);
if (sd_enabled)
{
// If Bluetooth is enabled, we need to go through the Nordic software to safely do this
sd_temp_get(&processorTemperature);
}
else
{
// Othwerwise, we access the information directly...
uint32_t *TEMP = (uint32_t *)0x4000C508;
NRF_TEMP->TASKS_START = 1;
while (NRF_TEMP->EVENTS_DATARDY == 0);
NRF_TEMP->EVENTS_DATARDY = 0;
processorTemperature = *TEMP;
NRF_TEMP->TASKS_STOP = 1;
}
// Record our reading...
temperature = processorTemperature / 4;
// Schedule our next sample.
sampleTime = system_timer_current_time() + samplePeriod;
// Send an event to indicate that we'e updated our temperature.
MicroBitEvent e(id, MICROBIT_THERMOMETER_EVT_UPDATE);
}
return MICROBIT_OK;
};
/**
* periodic callback.
* Check once every second or so for a new temperature reading.
*/
void MicroBitThermometer::idleTick()
{
if (isSampleNeeded())
updateTemperature();
}
/**
* Indicates if we'd like some processor time to sense the temperature. 0 means we're not due to read the tmeperature yet.
* @returns 1 if we'd like some processor time, 0 otherwise.
*/
int MicroBitThermometer::isIdleCallbackNeeded()
{
return isSampleNeeded();
}