Hello, currently I am developing an application for a pic 16c73, but we need the beef that 20MHz provides... until last week we were able to develop and tweak using the picmaster, but now we are running at 20 not 10 so I'm debugging what I can at 'half speed' on the picmaster then blowing an OTP for test. I've found that there are differences between the Vdd supplies when using the picprobe 16F and the OTP, I've tried the external power jumper settings, but I'm left with a little less than 0.2v difference. This affects the performance of the ADC readings, but it should be just a gain variance (ie, 0 = 0, and FF = Vref so the bottom end doesn't drift, but each digital increment is a different number of millivolts). I've also noticed that when using an OTP, there is sometimes a zero offset (although I'm not sure if it's an offset or just missing codes of 1 to 4). This isn't a problem per se (if I can understand the differences, I can design with it in mind), and the dependence of the ADC upon Vdd is documented in the databook... but is the ADC on the PIC 16c73 sensitive to ground in the same way that it is sensitive to Vdd? Pic sinks 2 amps and lives? if pic's could be blown up I'm sure I'd have managed it by now... >grin< regards, - Andy.