On Wednesday, Oct 29, 2003, at 20:48 US/Pacific, Robert Ussery wrote: > ----- Original Message ----- > From: > >> IIRC most of the AVR micros will only source about 2-5mA from an >> output port (they will sink more however). > > Not according to my handy-dandy AT2323_2343 "RTFM" manual. It says on > pg. 47: > "DC Current per I/O Pin.....................40.0 mA That's the "absolute max" rating. the io port descriptions make a big deal about 'pins can sink 20mA and thus drive LEDs directly" and don't say anything about sourcing current. There are graphs (pg 59 and 60 of the at90s1200 manual) that show pins sinking and sourcing reasonable amounts of current at appropriate voltage levels, but the source current capability seems to go down quite a bit at lower supply voltages. I don't know what circumstances will cause you to get 40mA into or out of a single pin, but i don't think you want to count on it being able to do that in normal operation. BillW -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.