JDM2 Based PIC Programmer




Schematic & layout for an updated JDM2 PIC Programmer. Includes clock & data filter, Vpp voltage divider for modern PIC microcontrollers (eg USB PIC 18F2455/4455).

Prior to reading sites like www.hackaday.com & www.makezine.com/blog I had worked only with the Amtel/AVR line of microcontrollers. After seeing all the cool projects people were doing with Microchip PICs, I HAD to have a PIC programmer. About a year ago I made my first PIC programmer based on the uJDM design (http://www.jdm.homepage.dk/newpic3.htm ). This programmer uses 6 common components. Though the link says '16F84(a)' only, I used it for the more modern (and cheaper) 16F628(a) processors without problems. This programmer has served me extremely well, but it is limited to (less than) 18 pin PICs with a programming Vpp of 13 volts.

This 'instructable' covers my new design that programs 8/14/18/28/40 pin PICs. The circuit is based on the JDM2 programmer (http://jdm.homepage.dk/newpic.htm ), with two enhancements: clock and data line filtering & selectable programming voltage.

The ZIP archive contains all the project files. The uJDM schematic and layout are included as well.

Step 1: Design Enhancements

Clock and Data Filter:

Newer PICs are programmed so fast that the clock and data lines can experience cross-talk. According to the author of WinPic programming software(http://www.qsl.net/dl4yhf/winpic/ ):

"There was a note on the Microchip forum (by Olin Lathrop) about programming the dsPIC30F201, suggesting to put 22..47 pF on the PGD and PGC lines to ground near the target chip. In addition, put a 100 ohm resistor in series with the PGD line between target chip and the cap. The resistor and cap on the PGD line low pass filter the PGD signal when it is driven by the target chip. This reduces the high frequencies that can couple onto the PGC line. The cap on the PGC line makes it less suceptible to coupled noise. We later found out that this important note also applies to the PIC18Fxxxx family. A user of a Velleman PIC programmer reported success with a PIC18F4520 after adding 2 * 33 pF caps and a 100 Ohm series resistor." (LINK:http://www.qsl.net/dl4yhf/winpic/#pgd_pgc_filtering )

This note applies primarily to programming PICs through a cable while they are soldered into a circuit. When using this type of programming the extra capacitors and resistor must be near the target chip - it does not help to have them on the programmer:

"This means that this problem can not be solved at the programmer end of the cable. No amount of clever circuitry at the programmer can make this issue go away. It must be dealt with at the target circuit. (LINK: see PGD to PGC Crosstalk at http://www.embedinc.com/picprg/icsp.htm )

I emphasize this so it is clear you CANNOT slap a ICSP header on this board without issue. I included the filters in my new programmer because the data/clock traces are long. The capacitors are situated in the circuit so that they can be excluded without weakening the trace. The resistor can be replaced with a jumper wire.

Selectable Programming Voltage (Vpp):

Programming voltage (Vpp) is applied to the MCLR pin to place the PIC in programming mode. Older PICs (12F/16F/some 18Fs) require a Vpp of 13 volts. Newer PICs (such as the USB enabled 18F2455/4455) have a lower Vpp of 12.5 volts. A voltage divider was added to the JDM2 design to provide 12.5 volts from the original 13 volt output. A diode prevents leakage through the voltage divider when it is bypassed. Vpp is selectable by the three pin jumper at the lower left of the programmer. In practice it doesn't seem to matter: I can program 13 volt parts with 12.5 volts, and 12.5 volt parts at 13 volts without damage.

Step 2: Construction

The traces in this design are nice and fat for easy toner transfer (or lazy photo boards). I started making PCB with the TT method, but found it pretty tedious. A $10 investment got me started with photo PCBs (using ink jet transparency positives). I will never go back.

All the parts were available at my local electronics shop in Amsterdam, though I ordered the parts from Mouser in bulk. Each board cost about $2.50 to make - the greatest expense was the 9 pin female DB9 connector ($1.60).

Layout and BOM are below. Schematic and board files are for EagleCad. Don't forget the 8 jumpers, shown in red.

Part Value

C1 100uF/25V
C2 22u/16V Tantal
C3 22...47...100pf
C4 22...47...100pf
D1 1N4148
D2 5V1 Zener
D3 1N4148
D4 1N4148
D5 1N4148
D6 8V2 Zener
D7 1N4148
IC2 DIL28-3
Q1 BC547B
Q2 BC547B
R1 10k
R2 1k5
R3 100ohm
R4 1K
R5 15K
SV3 Pin Header (3)
X1 Female DB9 9-pin connector (F09H)

Step 3: USE

The programmer will work with any programming software that supports the JDM2. I like WinPic800 (LINK:http://perso.wanadoo.es/siscobf/winpic800.htm ), and WinPIC also deserves credit for the great technical support info (LINK:http://www.qsl.net/dl4yhf/winpic/ ). Both support the newest USB PICs (18F2/4455). ICProg is great, but has not been updated in some time (LINK:http://www.ic-prog.com/ ).

This programmer has been tested with the following PICs:
Pins Part #
8 12F683
14 16F684
18 16F84(a)*, 16F628(a)*
28 16F737, 18F2455
40 16F74, 18F4455
*Original and 'A' revision OK.

Placement for various PICs is show in the diagram below. It is not limited to these PICs - it should work with any PIC that has Vpp, Vss, Vdd, PGD, & PGC arrangements as shown.

Step 4: Future Improvements

I used cheap AMP IC sockets from Mouser because I had them on hand. My next design will replace the 28 and 40 pin sockets with one 40 pin ZIF socket. A little extra clearance around the 18 pin socket makes a ZIF substitution possible as well.




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    124 Discussions


    3 years ago

    Can i use electrolytic 22uF/16V capacitor instead of tantal?


    3 years ago

    what is the sv3 bit for?


    3 years ago

    hi friend i am beginner of the pic programming i almost try with many
    circuits i need some help i work a lot for this pic programming
    i use pci card for rs232 the pin 3 output voltage comes only 11.5v

    but in the circuit the pin 4 9.4v

    and pin5,6,7,8,9 is 9.3v corresponding voltage

    its does not reach 12 or 13v for triggering mscl pin
    if i use to add a external power source it doesn't support please help me get out from thing headache

    and please feed some help to finished this one
    and mail me also venkat46c@gmail.com


    3 years ago

    Hi i have a question. Can u tell us the voltage of Vpp-Vss and Vdd-Vss. the circuit doesn't see microchip altough see jdm programmer


    4 years ago on Introduction

    Ok, I found my answer on the C3 and C4 values, one last question, what voltage rating for them?


    4 years ago on Introduction

    Hi all

    For C3 and C4 I don't understand why you have 3 values listed, is that one or the other?


    4 years ago on Introduction

    What software do you use for this? Sorry I am new to programming PIC's. Any recommendation are welcome.


    7 years ago on Introduction

    Is PIC16F690 supported? please reply. It is for my thesis. Thanks!


    7 years ago on Introduction

    Thanks mann..... I wanted to ask if i could connect a rs-232 to USB cable with it....


    9 years ago on Introduction

    Are you really sure this jdm2 proggramer supports:18F2xx0, 18F2x21, 18F2xx5, 18F4xx0, 18F4x21, 18F4xx5: 18F2221, 18F2321, 18F2410, 18F2420, 18F2423, 18F2450, 18F2455, 18F2458, 18F2480, 18F2510, 18F2515, 18F2520, 18F2523, 18F2525, 18F2550, 18F2553, 18F2580, 18F2585, 18F2610, 18F2620, 18F2680, 18F2682, 18F2685, 18F4221, 18F4321, 18F4410, 18F4420, 18F4423, 18F4450, 18F4455, 18F4458, 18F4480, 18F4510, 18F4515, 18F4520, 18F4523, 18F4525, 18F4550, 18F4553, 18F4580, 18F4585, 18F4610, 18F4620, 18F4680, 18F4682, 18F4685

    Today i will program Pic18F4550.. i hope it work

    2 replies

    7 years ago on Step 3


    Thanks for the simple design... Can I program attiny2313 which is a 20 pin IC with this programmer??


    1 reply

    13 years ago

    hi!i think that the pin 1 and 2 of the jumper must be conncted? if it's not right what's the role of this pin?thank you!

    4 replies

    Reply 13 years ago

    If the pins look like this (from the picture above):

    (x) (x) (x)
    1 2 3

    pin 1 and 2 *or* pins 2 and 3 should be connected by a jumper. In the picture above the jumper is between the middle pin (2) and the left pin (1) for low vpp.

    All this does is choose vpp from the standard JDM2 (13 volts) or a resistor divider network (12.5 volts). No big deal. I have found, in practice, that it isn't even needed. I program a 18f2550 by ICSP without the caps and vpp=13 volts with no problems.


    Reply 11 years ago on Introduction

    Hello everybody! I've a got solution for your problems with this programmer. The author of this project made a mistake. To make this programmer works properly, you should change few connections in cable, which connects programmer to pc: In RS232 pins have to be changed: pin 1 with pin 5 pin 2 with pin 4 pin 7 with pin 8 pin 8 with pin 7 For more question ask me by e-mail..


    Reply 11 years ago on Introduction

    Hello. I would like to ask, why when I program the microcontroller PIC16F84A using the programmer I have attached here is working but when I try to program the PIC16F877A it will not working. There is a problem when I try to verify it. By the way I used the PICALL software. What probably the problem? Thank you.