p.s: a blink for 40 seconds now gives me around 44secs (at over 5 Volts)
so it looks to me like it actually runsaround 10% slower on (9.6mhz -0.96) = at around 8.4 Mhz instead of the promised 9.6
is this normal?
The datasheet state the factory clock setting is within +-10%, so that is normal.
I was just playing with an ATtiny13 to see how close I could tune the osscillator, and it was quite easy to get within the +-2% mentioned in the datasheet by changing the OSCCAL value.
It is not very stable though, it jumps up and down.
One thing that surprised me:
Changing the OSCCAL dos not change the frequence of the 128 kHz internal Oscillator.