I'm working on a low power design using SAM D21 microcontroller (Adafruit Feather M0). I would like to take advantage of configurable I/O and have it normally in high impedance state, but reconfigure it temporarily to an input with built-in pull-down resistance in order to take a measurement once in a while, when the microcontroller is awakened from sleep state. Looking at the data sheet
Pull-up - Pull-down resistance is listed as 20kΩ to 60kΩ. I don't mind the wide range, I can calibrate, but is the value as stable as a typical external resistor would be? BTW, I don't need very high accuracy.
By stability, I mean low drift. For this project, change of 5% per year due to aging is acceptable. Thermal change of 5% in consumer electronic temperature range is acceptable too.
SAM D21 data sheet indicates that the pull-up and pull-down are disabled in analog mode. Thanks to @BruceAbbott for pointing it out.