AVR-Chat

AVR-Chat@yahoogroups.com wrote:
> On the mega48 part it is much the same. the internal RC is
> quite good over voltage and temp.
> BUT the osccal from atmel is only within something like 10%
> the data sheet will tell you.
> some parts the number is pretty good, like 2% I have not
> looked at the 162 to see what the spec is but I bet it is
> 'large'. If you try another part - it may be right on.
> 
> there is a pretty good appnote on how to use the STK500 to
> set the osccal for the voltage selected (and for whatever
> temperature you calibrate it at) that has worked well for me
> - you have to use a batch file, but once you have it - all is good.
> let me know if you want it - I can send you mine.
> 
You're right, it is 10%, so my 8.5Mhz is actually within spec. I've used
hundreds of mega8's and 16's and never come across one that far off. 

Unfortunately this is for a manufactured device so using the STK500 to
calibrate it is not an option. The manufacturing house uses a dataman
gang programmer, it might have a calibration option, I will check.

-- 
Tim Mitchell
tim@sabretechnology.co.uk
http://www.sabretechnology.co.uk