A JDM Mod Serial PIC programmer with VCC control

This project presents a JDM serial programmer to work with modern PIC families that require VCC control.

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This project is based on the JDM circuit for a serial JDM programmer with voltage control intended to be used with PICpgm, a free and simple PIC Development Programmer Software for Windows and Linux (

This project is based on the JDM circuit suggested on [1] for a serial JDM programmer with voltage control. This serial programmer is intended to be used with PICpgm a free and simple PIC Development Programmer Software for Windows and Linux that can be downloaded from here.

My main goal is get the JDM Serial programmer working with the PICs 12F1822 and 16F1824 which I've already programmed with the Microchip's PICkit3.



  • 4 × 1N4148 (Signal Diode) Discrete Semiconductors / Diodes and Rectifiers
  • 2 × 2N3904 (BJT NPN Transistor) Discrete Semiconductors / Transistors, MOSFETs, FETs, IGBTs
  • 1 × 2N7000 (N-Channel MOSFET) Discrete Semiconductors / Diode-Transistor Modules
  • 1 × 1N4733 (a 5.1 V Zener) Discrete Semiconductors / Diodes and Rectifiers
  • 1 × 1N4738 (a 8.2 V Zener) Discrete Semiconductors / Diodes and Rectifiers

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  • Prototype 2. - Testing again JDM Prototype 1 and testing a new one.

    Daniel Mejía Raigosa04/03/2015 at 19:19 0 comments

    I've reassembled the PICpgm programmer with VCC control. Though the programmer was recognized neither the PIC recognition nor the programming worked. Either the VCC control programmer suggested by the PICpgm team is not working or I'm assembling the circuit in a wrong way but is not working. May be the ICSP is not suitable for this Programmer. I need to test it out on a bigger breadboard.

    As an alternative for a JDM programmer I've tried assembling a Multichip programmer that I've found on this blog using the same circut except that

    • The NPN transistors used where 2N3904.
    • Ommited the LEDs thus the resistors.
    • The capacitor values where the same as on the circuit.
    • The resistor between CTS and DTR inputs was 1.8 kOhms

    This circuit is a kind of variation of the PICpgm JDM programmer without VCC. PICpgm recognized this circuit as a JDM programmer. The good thing is that the PIC12F1822 (my test PIC at hand) was recognized by PICpgm (auto recognized) and that's pretty positive. This apparently means that the voltage levels are just right at the pins, just enough to recognize the PIC.

    Figure 1. JSPVCv1.1

    Another circuit tested with the same results was the one on figure 2. Though when blank checking the PIC it said that the PIC was not blank at all. It was not possible for me to "clear" the PIC with this programmer.

    Figure 2. JSPVCv2

    Figure 3. PICpgm recognized the PIC and the programers but did not load the programm into the PIC. Both tested programers here showed the same behaviour on programming the PIC and autodetection



  • Prototype 1 - JSPVCv1.

    Daniel Mejía Raigosa03/31/2015 at 04:52 0 comments

    I've assembled the circuit of the figure 1. on a solderless bread board (figure 2.).

    The program PICpgm recognized the programmer but did not recognized the PIC12F1822 attached to it.

    Looking on the internet suggests that the problem can be combinations of

    • The PIC is damaged.
    • The connections are wrong
    • Wrong DC voltage levels on the programming pins of the PIC
    • Need of adding additinal components on the programmer (like Caps and stuff)
    • Wrong transistor connection (since the order of the pinouts could not be E-B-C looking the "face" of the transistor.)
    • Wrong delay setting on the PICpgm configurations.

    I have not tested the JSPVCv1 (JDM Serial Programming with Voltage Control version 1) with the PIC16F1824 given that the required programming voltage levels are pretty much the same. Annother reason is that i got lazy.

    I have decided to reassemble the whole circuit and test it again. Sorry, I've missed to take screen shots of the Windows GUI with the message "JDM Programmer" at "COM1" but that does not give much information, does it?.

    Figure 1. JSPVCv1 - Prototype 1 for serial JDM programmer with VCC control.

    Figure 2. JSPVCv1 assembled

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cribcat wrote 05/02/2017 at 00:52 point

The problem I had with my JDM homebuilt was that the hv just didn't have enough oomph to get to the 13v needed to program. I added a 13.5 volt power supply through a 1k series resistor. It's still a little touchy depending on what chip I use.

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