----- Original Message ----- From: Jinx To: Sent: Thursday, July 27, 2000 2:46 PM Subject: [EE]: Crystal oscillators > I was trying to knock up an external clock for the PIC. I say "was" > because every single can I tried, 8-pin base and 14-pin base, gave > a less than useful output. I've a selection of 30 from 4MHz to 50MHz, > mostly carefully salvaged from old PCs and a couple of new 10MHz > ones as well. Connection seems to be simple enough 0V, +5 and > o/p. AKAIK none use the fourth pin functions, I think they may be a > bit old, but I tried anyway. None give anywhere near a full logic swing, Pin that is left-out is unconnected on all examples. > most < 1Vpp and the best only +0.8 to +2, which isn't enough to use a > buffer gate. Looked up circuits using them and pdfs from Toyocom and > Kyosera but can't for the life of me see what the problem is. As per test > circuits, can supply is regulated and decoupled and a 15pF test load, > which seems to make no difference. Any suggestions ? I can't believe > all 30 are hopelessly stuffed. Well, not yet. I haven't had a chance to get > them in-circuit and do evil things to them. Try de-coupling +5V with both MKT and Tantal if you did not. Power supply should be "hard" Try looking on scope if it is stable or not. They should give +5Vpp as far as I know. I have one floating somewhere so I will try it myself and will inform you on results. Jerko Golubovic 9A6JGJ -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.