السلام عليكم
اخي كريم لاحظت من موقع التالي وهو السبب احيانا فشل البرمجه على 16f628
ولكن لم أفهم ذلك بالضبط
وهذا نص مشكله
Programming a PIC16F84 works, but programming a 16F628 does not work with my programmer - why ?
There is a major difference in the programming specifications. Most newer devices require a very fast rise on Vpp and / or Vpp (less than 50 microseconds between them) which is impossible with some of the "extremely simple" programmers I have seen on the web. The problem is, if the PIC starts executing its code because Vdd (the supply voltage) is present, but Vpp (the programming voltage) is not raised to say 12 Volts fast enough. So the program counter will not be zero when entering programming mode, and programming will fail for this reason. Get or borrow a two-channel oscilloscope and measure these voltages. If there is a slowly rising edge on the Vpp pin, throw those large electrolyte caps out to make the rise time faster. Or, invest a few pennies / cents for a few transistors and build a better interface.
There is a workaround for this problem when using the JDM programmer: WinPic sets all control lines HIGH for about 500ms, which should discharge all capacitors, before applying the Vpp voltage. I tried this successfully with a PIC12F675, where the MCLR-input had been disabled previously, and had no problem when trying to overwrite the chip. If this doesn't work with your JDM programmer, let me know, maybe making the 500ms discharge interval even longer helps. About the JDM programmer and oscilloscopes: DO NOT CONNECT THE OSCILLOSCOPE TO THE PIC'S GROUND - the scope's ground will most likely be connected to the PC's ground, which causes a short circuit for the JDM programmer's tricky supply voltage !
ويبدو ان احيانا سبب مشكله حسب ماأفتهمت هو عدم أرتفاع VPP الى 12 فولت بالسرعه التي يحتاجها مايكروكنترولر
طبعا هو تكلم عن الحل ولكني لم أفهم ذلك ولربما يقول لك أربط مكثف الالكتروليتي ليساعدك في حل مشكله
طبعا الجأ الى هذه مشاركه في حاله وصلت الى مرحله اليأس ولم تنفع كل الحلول التي طرحت اعلاه
طبعا كلام الذي اخذته من هذا الرابط
http://www.qsl.net/dl4yhf/winpic/winpic_faq.htm
