JDM Pic Programmer Problems

Testing/Troubleshooting
1

Hello, I am new to the group, but glad to see someone has a decent community supporting this kind of thing!

First off, I have read the walkthrough, and the other like 4 threads discussing the JDM here, and all the details on it… I have also visited the newsgroups for embedded devel, and read many other troubleshooting guides…

I am building a PIC Programmer that is my own PC Board Design, it is for writing 16F84, and 12C508/509 chips. So it uses a small socket and a different layout… But it is based exactly off of the schematic at:

http://www.jdm.homepage.dk/newpic22.gif

I am using ICProg to try and write data, but when I read all, it returns all 3FFF and blank check works, but when I try to write it fails at 0000h.

An interesting thing to note, is that it reads 3FFF even if there is no pic in the socket at all…

Also, if I unplug the JDM from the serial port, then it reads 0000 instead of 3FFF so I know the programmer is doing something…

I have double, triple and quadruple checked my PCB with the schematic, and I did find a problem, so it has been repaired… I have tried adding the resistor inline with ground as per JDM, as well as adding external power source. I have tried various sets of configs in ICProg, (I am running WinXP but I have the driver installed properly, and I have tried with api, and direct using and not using the driver) Also I tried all the hardware test steps…

this is the results of the hardware test as per your walkthrough:

MCLR - 4.3V steady, with or without MCLR Checked in ICProg

VCC - 4.7V Steady when checked, but when unchecked it slowly falls off to 0v

Clock - When Unchecked it is -0.72V Steady, when checked it spikes to 3.3V then slowly drops off…

Data Out - When unchecked it is -2.45v stable, when checked it is instantly 4.17v Stable.

Read All (With 16F84A):

MCLR Seems to drop from the 4.3V State and fluctuate a bit, but it ends up around 0V then when read all is done it jumps up to 4.3V Again.

VSS exibits the exact same behavior.

Then I got frustrated, so I built a brand new JDM from scratch thinking it might be component failure, so I tested my components, and rebuilt completely from scratch, and the second programmer is doing the exact same thing…

I can post my PCB Design and such as well if it is relevant, but I have checked it a million times, it matches that schematic perfectly… And I know there are no bad traces or anything (checked them all before fabricating with multimeter, as well as blew up the PCB in scanner to like 100x so that I could inspect visually…

I would appreciate any help anyone can give me, as I am getting very frustrated with it, but I really want to get into PIC programming bad…

Thanks

  • Paul

(Oh, and anyone who wishes can email me at: glasswalker@iam-net.com)

thanks.

2

Hi Paul,

sounds familiar to me…  ;)

In fact I built a JDM a few days ago and had quite similar difficulties.

My first advice is to check your design again and then check your design again and then double check your design again. Sounds dumb I know but this is what helped here.

When you’re sure your PCB is ok and decently soldered then I’d suspect the Zener diodes. Have you used 1/2 Watt types? I didn’t and they got quite warm and finally were not reliable (took me some time to find out) anymore.

I replaced them by two voltage regulators, 7805 and 7812 (with two 1n4148 from REF to ground), and use a small (3 VA) 15V transformer to feed them.  That made all voltages perfectly stable.

(mail me if you need a schematic)

Since then I had no problems anymore.

SB

mailto: jsmoothj@hotmail.com

3

Thanks for the feedback… I will give the Voltage Regulators a try later on as well, I would appreciate an email at glasswalker@iam-net.com with the schematic if you have it…

But I know that the schematic (and PCB) I used works, because I sold one from the batch I etched to another guy and he built it and it worked fine… with the exact same components I used…

I have tried it on 2 different PCs now, but both exibit the same behaviour… is there anything else anyone can suggest?

4

>>MCLR - 4.3V steady, with or without MCLR Checked in ICProg

If I’m right, the voltage should much higher there (about 13.7V). Looks like your JDM is faulty.

Doc

5

If I’m right, the voltage should much higher there (about 13.7V). Looks like your JDM is faulty.

Doc

Uhh… hehehehe… I knew that…

:slight_smile:

Just want to know any suggestions on how to troubleshoot it properly :slight_smile: hehehe… So that I can determine exactly WHY it is faulty, and then correct the issue so that I can start using it.

Oh, and thanks for the schematic sexybeast! :slight_smile:

6

Ok, I have built a 3rd from scratch brand new components… Triple checked all solder connections and placement… Took a multimeter to each stage in the schematic to make sure connections were good and components appear fine…

And everything matches the schematic from the original JDM homepage…

But same error…

on more than one PC…

Triple checked the software settings… all correct as per your walkthrough on this site…

Does anyone else have any other suggestions?

Please???

I AM EXTREMELY DESPERATE AND FRUSTRATED!!! :slight_smile: hehehehe