problem with calculating internal tempwerature with STM32F105

[wadi]

Posted on May 16, 2012 at 23:26

Hello

I have a problem with calculating internal temperature with STM32.

When processor VCC is 3.3V everything is ok - temperature is almoast accurate with wide temerature range.

But whet processor VCC is below 3V temperature falls much below zero ( -40stC, -100stC etc...).

Where can be a problem ?

with best regards

[Tesla DeLorean]

Posted on May 17, 2012 at 01:27

Where can be a problem ?

Perhaps you can provide some details of the measurements and the math, and how you account for the voltage, that way people might be able to make informed suggestions rather than guessing what the problem is.

[frankmeyer9]

Posted on May 17, 2012 at 10:57

Sounds like a problem with the ADC reference voltage.

There is a ADC channel reserved to measure Vref, adjacent to the internal temp. sensor (IN16, IN17).

Do you use a package with external Vref pins ?