Thanks. Looking at the 644A data sheet (which encompasses the 1284[P]), there's no difference in the typical characteristics between letter variants of a particular processor memory size. There is a very small difference in the "max" values for power consumption.
On Feb 8, 2011, at 14:02:49, Ruud Vlaming wrote: > On Tuesday 08 February 2011, Rick Mann wrote: >> I'm working with the ATmega644A, and I like it, but I could use more memory. >> >> So I'm looking at the 1284, which comes in a P variant, >> but no A variant. I can't figure out what the differences among all >> these variants are. The 644A comes in a PA variant as well. > Indeed this P/A business can be confusing. For most chips the > only difference between P en non P is the power consumption > and the possibilty to operate the chips at lower voltages. > A or non A makes much less a difference, usually only > small differences in electrical characteristics. For example: > 1284P : V_OLmax (Vcc=5V) 0.7V > 644PA: V_OLmax (Vcc=5V) 0.9V > i cannot find the datasheet of the 644A, so i have no > real comparrisson at the moment. > > My guess is however that you should be save if you > replace an ATmega644A with an ATmega644PA > or with an ATmega1284P for that matter. > I would in general not replace it the other way around. > > One other point of attention: the ATmega1284P used to > have some availability problems, but maybe this is > history by now. > > Hope this helps. > > Ruud > > _______________________________________________ > AVR-chat mailing list > [email protected] > http://lists.nongnu.org/mailman/listinfo/avr-chat _______________________________________________ AVR-chat mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/avr-chat
