Erik Hermann wrote: > I've designed a very easy and cheap but nevertheless comfortable > PIC 16C84 Programmer using the PC's serial port. Brilliant! I was puzzled by your earlier post saying that AN589 was too complicated, but now I can see what you meant; you are even pressing the PIC internal protection diodes of into service to save components. Let me pass on my admiration of a truly original approach. I notice that the 12V minimum VPP spec in the datasheet applies for entry into programming mode and only 9.5V is needed for programming. Still, I guess this is the only less than ideal aspect of your programmer and I haven't any experience of its implications for the long term retention of EEPROM contents. One thing that has puzzled me for a long time is the datasheet "supply current from VDD during program/verify" spec of 50mA maximum. Obviously your design can't meet that spec, but then again I have never come across a PIC that needed even an order of magnitude less than that rating. By the way, is your Pascal source available anywhere? David -- david.tait@man.ac.uk