Incorrect scaling of analog input voltages

[jwbonner]

We've been testing the Smart IO ports using 3.3v analog absolute encoders. When the encoder is at the maximum position before wrapping, we've confirmed manually that the output voltage is ~3.3v (as expected). However, this value is reported as only ~2.2v when reading it as an analog input through SystemCore. Other input voltages scale continuously from 0-2.2v instead of 0-3.3v as expected. With an encoder output of 3.3v, the raw integer value for the analog input is ~2700.

[bhjelstrom]

Some coordination is happening now to figure out where to implement the fix (didn't get around to it for the first release):

If you want to implement something on your end temporarily:
voltage = max(0,(adc * 0.0011949)-0.1448)

[bhjelstrom]

Fixed in the next release - the raw reading is now millivolts instead of 0-4096

[ThadHouse]

Note that change might break wpilib. We can provide a workaround when it happens if teams need if we don't have a release in time.

[Kevin-OConnor]

getVoltage appears to be working correctly in WPILib Alpha 2 with image Alpha 5 (Release 166)