K10 temperature sensor delay

[bgra]

Hi everyone!

We have designed somes boards including Kinetis K10 72MHz MCUs (64 & 100 pins).

ADCs are referenced with an external 0.1% 2.5V.

We are using the embedded temperature sensor by applying the conversion equation given in the reference manual.

The problem is, if in "steady state" the calculated temperature is correct (we don't need a high accuracy on this measure), the time required after the boot before having a valid value is almost 20 to 25 seconds. During this period, the equivalent temperature given by the microcontroller is about 12°C (for an ambiant of 20-30°C), and all other values given by ADCs are correct.

We certainly missed something in our software configuration, but we can't find the error. Can somebody help us on this point?

Thank you in advance for your help,

Brian

[egoodii]

We could certainly look at your firmware for this function.

I've not known of any cause for 'delay in operability'.

I assume you have read my treatise on the subject:

On-chip temperature Calculations 

You say 'other values given by ADC are correct', then I can assume there are 'some other' absolute-voltages coming in that give the 'right answer' from the get-go?