Picture of 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

Picture of 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.
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brcoenen7 months ago

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

brcoenen7 months ago

Hi all

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

brcoenen7 months ago

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

jomar_000123 years ago
Is PIC16F690 supported? please reply. It is for my thesis. Thanks!
wimpieA3 years ago
Is this programmer going to work with MikroC?
aaim3 years ago
Thanks mann..... I wanted to ask if i could connect a rs-232 to USB cable with it....
levonTech185 years ago
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
did it work for pic18F4550 ?? please reply on dhiraj_dt@yahoo.co.in
hey, did it work? I really need to program an 18F2550 for my project.... thanks


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

ian (author)  viswanathmarachi3 years ago
I think only PICs.
sim9 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!
ian (author)  sim9 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.
kubeqz ian7 years ago
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..
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.
just try to connect GND with PGM
vkumar kubeqz6 years ago
Hello Kubeqz Is Null modem cable to be modified or can I use as it is ? to connect PiC Programmer to PC vkumar
ian (author)  kubeqz7 years ago
I think the reason is that you are using a null modem cable -- a cross over cable for two computers.
noxx3 years ago
Ian I can't open the files that have .brd and .sch extensions. which application do i use to open to them?
ian (author)  noxx3 years ago
Cadsoft Eagle.
noxx3 years ago
pls can someone answer me. how can i view the .sch and .brd files?
efdat3 years ago
please tell me the soft ware you use to draw your pcb circuits
anatesan3 years ago
can we program pic18f4550 and pic18f2550 using this
C.H3 years ago
I have not built this yet and I read you mentioned using a ZIF socket. Using a ZIF socket instead of several different sockets will spare resources and ease the design I guess. :)
I have a ZIF socket and am wondering where you would put it to make your programmer work as intended. (I have yet to build anything electronic, this PIC programmer will probably be my first project)

Thank you!

- C.H.
mujtaba ali3 years ago
is it program to 16f877a microcontroller ic?plz reply

ian (author)  mujtaba ali3 years ago
should be ok
zacknie4 years ago
is it working on PIC16F84?..
cavemen4 years ago
Can i replace rare BC547B with 2n3904?
I already did.
the board ain't working with my pic16f628
trying to figure out why
Try flipping transistor around. the BC547B is CBE and i think the 3904 are EBC
instbubba4 years ago
The Eagle schematic has a problem, the transistor's pinout for the one that goes to Vpp is backwards. The collector and emitter are reversed. It may not affect the board, but the schematic could not possibly work the way it is apparently wired.

FYI, for an easy to understand diagram of this circuit, take a look at the Olimex PIC-PG2. This circuit is essentially identical with the addition of the filtering networks.
nikon954 years ago
Will this work with my 16f877 and picpro (linux)???

Αny tips would be appreciated .

homermike5 years ago
Hello... We'v been dealing a lot of projects using PICs... and now we come up to a project that we could do the PIC programming on AIR using GSM module.. So i would like to ask if someone had an idea on how to make a system that have 2 PICs.. one PIC is the MAIN PIC and the 2nd PIC would be the program or HEX loader PIC to the MAIN PIC...
obie875 years ago
hi, i want to know if this Programmer can program PIC 16LF628A, Thanks
levonTech185 years ago
D2- must be : 1N4733 5.1v 1w  .....And D6-Must be : 1N4738 8.2v 1w

Thanks < i hope this can help you to build ..
levonTech185 years ago
Hi< do you really think this is working and can program PIC18F4550..
naveen.a0195 years ago
hi,  why do u need ...sv3...i am a newbie to electronics hobby...can any bdy..help...


cm6lar5 years ago
I think that the Q1 transistor is not corrected placed.. the emisor an collector are bartered.
monsterman5 years ago
dous anyone know if this will work with a 18F2550
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