Spent a bunch of time today trying to program a few different devices but ran into some walls. First up was a 16F818 which programmed successfully only a few times, intermittently. Two fresh F819s did the same. Google and other resources told me that the F818/9 are funny animals w.r.t. programming, but trying all the suggestions I could find, it still did not work. I tried these with a quickly-hacked-together JDM clone with IC-Prog, and a commercial ICD2 clone with MPLAB 7.30. FWIW, both of those programmers can successfully program 16F872's and 16F628's, so I trust that the programmers work. So I took a break from that and switched to another chip -- the 16F88. With the ICD2 & MPLAB, I was able to successfully program this device, with MCLRE on (serving as a reset pin). When I changed MCLRE to off, programming failed. Since that, the programmer fails to recognize the 16F88's device ID anymore and fails programming. Google found me some info that indicated newer PICs can get locked up in this way and un-reprogrammable when both internal-oscillator and MCLR-as-IO was selected, but I had been using the external RC oscillator config setting throughout all of this. I had another fresh 16F88, but it did the same thing -- after changing the config bits in the code to use MCLR as a reset pin, it won't re-program. Arrrggghhh!!! I'm stumped, and frustrated. So my questions -- if some PIC's require Vdd-before-Vpp, why doesn't the ICD2 control Vdd? Are the 16F819 and 16F88 really Vdd-before-Vpp devices? I've never really read-thru any programming specs before, but maybe I'll check one out. Most importantly is what I can do at this point, and is there really a programmer that properly supports the 16F818 and 16F88? From some research, the F88 should be easy, but I'm not sure why it locked up. The F819 appears to be problematic, but there must be a supported programming HW/SW combo that works for this, right? Cheers, -Neil. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist