Mike asked: > We need in circuit programability and we curently use a PRO MATE > with the ICSP module. Is this going to work for 3.3 volt parts? I'm not aware of those parts being 3.3 V only. I thought they were guaranteed to run at 3.3 V to 5V, in which case you can program them with Vdd at 5 V. BUT, this might prove a challenge for in-circuit programming though, if the rest of the board can't be at 5V. > It looks as though Vdd can be adjusted from within the programming dialogue in MPLAB. > Has anyone tried this? Well, typically, programming is done at nominal Vdd, and verifies are performed at both high Vdd and low Vdd to make sure that the thresholds are all programmed right. I have used that feature to make sure that the verifies were done at the right "high" and "low" voltages for my 16LC76. I want to make sure it will keep running a 3.3 V, even though I program at 5 V (out of circuit). Sorry, I don't know how Vdd is set for parts with 5 V only programming, does the "Vpp" setting change Vdd during programming? The docs I have use an example with Vpp = 13V! FWIW, Barry ------------ Barry King, KA1NLH NRG Systems "Measuring the Wind's Energy" http://www.nrgsystems.com Check out the accumulated (PIC) wisdom of the ages at: PIC/PICList FAQ: http://www.piclist.org -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.