measure the xtal

[skimask]

Hi, Savnik
An easy solution is to use an external RC circuit and use ... RCTime ( 16 Bits result ...) !!!
calibrate RCTime ( low drift components !!! ) with a Known Freq XTal ...
With another XTal The Result will be proportionnal to the XTal Freq change ...
That's all, Folks !!!
Alain

Won't the output from RCTime be a logarithmic response, in other highly non-linear? You'd probably have to do some serious math to get accurate results.