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However, an issue has arisen lately with some of the new PIC's, eg PIC12F675, 12F629, and some others with an internal oscillator.
When these chips are programmed the first time, everything goes fine. However, if you later try to read or re-write to them, they read as blank and cannot be written to. The problem only occurs when the PIC has been programmed for INTOSC and MCLR_OFF, but even in this situation sometimes it will re-program OK - there seems to be some other dependence on the program which has been loaded as well.
The cause of the problem is that the JDM programmer applies +5V Vcc to the chip all the time, and cannot effectively be turned off, as the serial port ground connection is actually used for Vcc. This means that when the PIC has been programmed for INTOSC, the program in it runs as soon as it is inserted into the programmer. Once the PC increments with the program running, the device is no longer in a reset state and will not enter program/verify mode. The other issue is that if the PIC program writes values to data EEPROM memory which depend on the state of the inputs, these values will be overwritten and lost when inserted. For those who have encountered these problems, the advice has been to build a new programmer, eg. the Tait programmer, or there is
Feng's "RCD Programmer" which he develepod as a result of this problem, and is fully compatible with the JDM.
). Men så idag när jag skulle använda den igen funkar det inte. Jag har testat både "IC-prog" och "Win PIC Programmer". I "Win PIC" står det att programmeraren är initierad och funkar, men när jag programmerar misslyckas verifieringen och det står "programming failed".
