I'm using this PIC at 40 MHz with 2 Megabytes of external SRAM. (10 MHz with the 4X PLL.) However, I've noticed a warning note in the external memory section of the Spec. manual. Something about only running at 25 MHz. when using external memory. So far I've had no problems, but... I wonder what is the problem? I have not been able to get any answers from the Microchip web site on this problem. (It is likely I didn't look in the correct place...) Tom -- * | __O Thomas C. Sefranek WA1RHP@ARRL.net |_-\<,_ Amateur Radio Operator: WA1RHP (*)/ (*) Bicycle mobile on 145.41, 448.625 MHz http://hamradio.cmcorp.com/inventory/Inventory.html http://www.harvardrepeater.org -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist