[TriEmbed] ATTiny84A internal temp sensor: how good?

[Pete Soper]

The internal sensor in the ATTiny84A stinks without calibration. What I 
can't find in the datasheet (section 16.2) is how good it can get with 
additional calibration points. Would it be reasonable to expect to make 
it accurate to +/- two degrees C across a 0 to 70 degree range if I can 
calibrate it across the full range and refine the slope measurement or 
is the linearity likely to be too poor?

-Pete