TK. Posted August 24, 2003 Report Share Posted August 24, 2003 Last week I got a PIC16F877A which wasn't programmable with my own JDM, although I burned a lot of ..A chips with this programmer before. I noticed that the voltage at MCLR# was lower than on a "common" PIC16F877A. It didn't help to vary the software settings of IC-Prog like IO-Delay or Interface type of IC-Prog, so I finally tried to increase vpp by using an external PSU - with success! Maybe (or hopefully) this is the solution for everybody who wasn't able to burn a PIC (especially the new ...A and the PIC18F types) yet:use either two 9V batteries or a PSU which delivers at least 15V. A regulator isn't required, the zener diodes limit the voltagedon't forget the 220 Ohm resistor - it limits the current and protects the circuitplug the PIC directly into the JDM module socket when you burn it the first time, because an erased PIC requires the pull-down resistor at pin RB3 which disables the low-voltage programming mode.Good luck!Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
ladybug Posted August 24, 2003 Report Share Posted August 24, 2003 and what about the "pre-flight-check" ??should i do it as on the site and get the same results ?or is it different now ?is the change good for all the other pics ? Quote Link to comment Share on other sites More sharing options...
TK. Posted August 24, 2003 Author Report Share Posted August 24, 2003 This mod improves the MCLR# voltage, use it if the output voltage of your COM port is not high enough. The checks are still the same.The results are "improved".The derivative doesn't matter here. Just try it with an external supply if your JDM doesn't work (with a certain PIC or with any PIC)Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
Steven_C Posted August 25, 2003 Report Share Posted August 25, 2003 Thats great that you were able to solve this problem Thorsten! ;D Quote Link to comment Share on other sites More sharing options...
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