Altitude Posted June 7, 2010 Report Share Posted June 7, 2010 (edited) So I have completed my 5th GM5 module and have an issue. When plugged in, I get a "USB device not recognized" error (win7 64bit) Here is what I have checked: Power on GM5x5x5 to all relevant pins on the GM5 chip connections via the 27 ohm resistors No shorts, all relevant components correct Any windows issues (midi device limits, various USB ports, etc to eliminate win issues) I suppose this leaves the crystal and the chip itself. For the crystal, I tried it initially with the 22 pF load caps and then switched to the manufacture recommended 18 pF with the same result. This is the same crystal that I used for my other 4 modules (2 5x5s and 2 1x1s) so I know it should work. When I probe the crystaks leads on my 20 MHz scope, I dont see anything that looks like a clock signal. Are bunk crystals even remotely possible? I soldered in the GM5 chip normally without any problems and everything was inspected with a high powered lupe, I do these size chips regularly (I build x0xb0xes on the side) so I am comfortable I did not fry it (or maybe i did?) Any thoughts appreciated.. Edited July 20, 2010 by Altitude Quote Link to comment Share on other sites More sharing options...
nILS Posted June 7, 2010 Report Share Posted June 7, 2010 Is it a gm5 module or gm5x5x5 module? Have you stuffed the appropriate jumpers? (Easy and safe thing to do is to set all jumpers)? What does the main LED do when you plug it in? Frying the small Atmels seems impossible, and believe me, flexinoodle seriously tried :D Quote Link to comment Share on other sites More sharing options...
Altitude Posted June 7, 2010 Author Report Share Posted June 7, 2010 Is it a gm5 module or gm5x5x5 module? Have you stuffed the appropriate jumpers? (Easy and safe thing to do is to set all jumpers)? What does the main LED do when you plug it in? Frying the small Atmels seems impossible, and believe me, flexinoodle seriously tried :D This is 5x5x5 v1.0 board with all jumpers stuffed. The main LED is continuously lit when plugged in. Good to know that GM5s are hard to fry, though my SMD Kung-Fu was in peril there for a minute.. So this leaves the crystal? Quote Link to comment Share on other sites More sharing options...
nILS Posted June 7, 2010 Report Share Posted June 7, 2010 If the main LED is constantly lit the gm5 isn't properly initialized. So I guess, that leaves the crystal or a dead gm5. Quote Link to comment Share on other sites More sharing options...
Altitude Posted June 8, 2010 Author Report Share Posted June 8, 2010 If the main LED is constantly lit the gm5 isn't properly initialized. So I guess, that leaves the crystal or a dead gm5. Crap. looks like the chip is kaput. Time to buy some quick chip.. Quote Link to comment Share on other sites More sharing options...
nILS Posted June 8, 2010 Report Share Posted June 8, 2010 Since you have a scope - did you try to check the signals on your working gm5s' crystals? Quote Link to comment Share on other sites More sharing options...
Altitude Posted June 8, 2010 Author Report Share Posted June 8, 2010 Since you have a scope - did you try to check the signals on your working gm5s' crystals? Yep. Nice 16mHz cycles. I even switched the crystal that I know is working with the one on the board that has the problem and the results were the same. Put that crystal back on the 1x1 i took the other one from and it checked out. Very strange, static shock maybe? Quote Link to comment Share on other sites More sharing options...
nILS Posted June 8, 2010 Report Share Posted June 8, 2010 I guess you have no shorts or broken traces around the crystal? Are the caps properly grounded? Is the other leg of the caps accidentally grounded? If all that is the case, I guess it's really the gm5... Quote Link to comment Share on other sites More sharing options...
Altitude Posted June 8, 2010 Author Report Share Posted June 8, 2010 I guess you have no shorts or broken traces around the crystal? Are the caps properly grounded? Is the other leg of the caps accidentally grounded? If all that is the case, I guess it's really the gm5... Yeah, I traced everything back to the clock pins and everything looks right, I'm stumped. Quote Link to comment Share on other sites More sharing options...
Altitude Posted July 20, 2010 Author Report Share Posted July 20, 2010 Solution: Replace GM5 New GM5 problems disappeared. Looks like the chip quick gets the chip really hot and I must have fried it.. Quote Link to comment Share on other sites More sharing options...
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