Spehro Pefhany wrote: > Quoting lk : > > i am wondering if my selfmade TQFP 80 adapter is working well. > > Maybe You can just look at the picture and tell me if it is basically > > possible to get it to work with such an adapter. > > Of course there are no hazards! > > I ve red that the oscillator should be as near to the OSC pins as > > possible. Using that adapter it cant be close at all... > > I already have run a simple LED blinking program on that chip, but am > > not sure if everything worked well. > > Is there generally the possibility of crosstalk et cetera? > > There are not much information i am giving You, but maybe You can give > > me some advise by just looking at the picture. > > > > http://home.arcor.de/luka5/DSC06977.JPG > > Traces are pretty narrow-- it might be a good idea to widen the Vdd/Vss > traces and maybe add a bypass cap or two near the TQFP, even if you need > to add wire jumpers. Take it a step further than that, even. Instead of a "totally generic" QFP80 adapter, make one that's specific to the chip (or family of similar chips) insofar as providing the power and ground connections, bypassing, crystal/oscillator, reset and a programming connector. This (once debugged) will make all of these non-issues in any particular application. You might check out Stuart Ball's article, "Prototyping with QFP Parts", in Circuit Cellar #218 for further thoughts about this approach: http://www.dtweed.com/circuitcellar/caj00218.htm#3698 If you want to plug it into a white breadboarding socket, consider having the adapter span four rows rather than just two. This would make it about 2" square rather than 4" long. Obviously, this means that half of the connections would need to be made before you plug the adapter into the socket, but if the pins are long enough, this shouldn't be too much of a problem. x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x +---------------------------------------+ x x x x|o o o o o o o o o o o o o o o o o o o o|x x x x | | | | | | | | | | x x x x|o o o o o o o o o o o o o o o o o o o o|x x x x --- | | ^ x x x x| |x x x x | | | | x x x x| |x x x x | | | | x x x x| |x x x x | | | | x x x x| |x x x x | | | | | | | | | | | | Make Power x x x x| |x x x x this Rails | | length (opt.) x x x x| |x x x x match | | your | | setup. | | | | | | x x x x| |x x x x | | | | x x x x| |x x x x | | | | x x x x| |x x x x | | | | x x x x| |x x x x | | | v x x x x|o o o o o o o o o o o o o o o o o o o o|x x x x --- | | | | | | | | | | x x x x|o o o o o o o o o o o o o o o o o o o o|x x x x +---------------------------------------+ x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x With regard to your existing adapter -- How well does the chip run when configured with its on-chip oscillator? Try writing some small test programs in that mode to exercise the I/O and pin down what is or is not working. -- Dave Tweed -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist