Extend the ADC out of range check so that it is possible to sample
multiple times before going into a shutdown state. This reduces the
chance that measurement noise will cause an error. In an actual over
temperature (or under temperature event) it is expected that the
sensor will consistently report the problem, so extra checks for an
additional second or two should not substantially increase risk.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
If the c3 coefficient is negative it can cause the adc calculations to
fail. The c3 shouldn't be negative in practice, so fallback to a
simple beta calculation in that case.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Move the Thermistor code to a new thermistor.py module. Move the
Linear code to a new adc_temperature.py module. This simplifies the
heater.py code.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Kevin O'Connor