I would make a small LC tank centered at 12Mhz across a scope input with a= n arial close to the xtal and use a scope output into a frequency meter although a good scope would measure the freq as well=2E You could write a program to help you - either using the timer/counter if you have one of just a loop that outputs a pulse based on NOPs and a jump = - this would allow you to measure, but this will divide the 1Hz resolution you are looking for unless you use a big divide and an equally big count time=2E Just a few thoughts=2E Veronica, somewhere in Cambridgeshire, UK "The best things in life aren't things" Original Message: ----------------- From: Peter Crowcroft peter@KITSRUS=2ECOM Date: Mon, 12 Aug 2002 18:12:05 +0800 To: PICLIST@MITVMA=2EMIT=2EEDU Subject: [OT]: What Test Gear to measure xtal frequency to 1Hz We are using a 12=2E000MHz crystal in a timer circuit=2E It has 2 x 33pF l= oad capacitors and the xtal is under the IC socket so the tracks to the uC are= 0=2E15" only=2E We want to measure the osc frequency to within 1Hz so we can adjust the load cap in one leg=2E Can someone tell us what test gear we need to be ab= le to do this? regards, Peter Crowcroft DIY Electronics (HK) Ltd PO Box 88458, Sham Shui Po, Hong Kong Factory: voice 852-2304 2250 Fax: 852-2729 1400 M/F, 97 Fuk Wa Street, Sham Shui Po Home: voice 852-2720 0255 Mobile: 6273 2049 Web: http://www=2Ekitsrus=2Ecom Email: peter@kitsrus=2Ecom Yahoo Messenger 'peter5999' with webcam Pay with Paypal: peter@kitsrus=2Ecom ------------------------------------------------------------- -- http://www=2Epiclist=2Ecom hint: The PICList is archived three different ways=2E See http://www=2Epiclist=2Ecom/#archives for details=2E -------------------------------------------------------------------- mail2web - Check your email from the web at http://mail2web=2Ecom/ =2E -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.