Measuring VCC voltage

[metehoca]

I'm using an ATtiny3216 (or ATtiny816) with a 1V2 external analog reference. Is there a way to measure the MCU's supply voltage without using any ADC pins?

EDIT: My bad; https://github.com/SpenceKonde/megaTinyCore/blob/master/megaavr/extras/Ref_Analog.md#measuring-vdd-on-01-series

[metehoca]

I get "'ADC_INT_REF' was not declared in this scope" error.

[jvasileff]

The example code uses ADC_INTREF

https://github.com/SpenceKonde/megaTinyCore/blob/master/megaavr/libraries/megaTinyCore/examples/readTempVcc/readTempVcc.ino