In message Mike Harrison wrote: > Small 3V coil relays were hard to find when I was looking (can't remember > if they were not listed, > or just out of stock at the time), 4pco in 3V is probably unobtainium so a > pair of 3v ones may be > needed.. Hmm, not too bad... > My setup powered the isolator from the host power, on the basis that it > would always be there, and > allowed the isolator to be a simple in-line addition to the ICD cable. > There would be some benefits > to tapping into the 5V supply within ICD2, one of which would be the > ability to use more easily > obtainable 5v relays. Maybe just mod ICD2 to put 5V down the unused pin on > the RJ connector. You could tap 5V off the ICD, but that would mean hooking it up to a PSU and remembering to plug in said PSU before programming. I doubt the ICD's internal PSU could handle two extra relays chained off it. > So you just want protection, not isolation. 3W 5.6V zeners on the data and power lines, and 14V on > MCLR should be more than adequate. If you have something that blows these your target board will be > serious toast anyway... I'm thinking more along the line of "If my target board gets seriously toasted, I want my $$$EXPENSIVE$$$ ICD2 to survive the encounter". Chances are, I'll have spares for the target, but the ICDs cost serious money when you're on a student budget. Thanks. -- Phil. | Acorn RiscPC600 SA220 64MB+6GB 100baseT philpem@dsl.pipex.com | Athlon64 3200+ A8VDeluxe R2 512MB+100GB http://www.philpem.me.uk/ | Panasonic CF-25 Mk.2 Toughbook ... Be Nice to Your Enemies, It Drives Them Nuts. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist