# PIC Programmer "JDM 2"

#### Leccy-Lee

Joined Aug 2, 2008
22
Hi

I was about to build myself a JDM 2 Programmer for use on some pics, as i found this schematic online. One question though, its connecting to a 9pin serial plug, so where does that pin20 connection go (1.5k resisitor), as theres obviously only 9 pins?

#### hgmjr

Joined Jan 28, 2005
9,029
The pinouts are given for the 25-pin serial port standard.

hgmjr

#### Leccy-Lee

Joined Aug 2, 2008
22
Would this not work fine though on a newer 9pin serial just the same? I figured it should if i can work out the pin 20 thing..

#### hgmjr

Joined Jan 28, 2005
9,029
Here is the wikipedia information on RS-232 pinouts for the 9 and 25 pin connector. It should work fine connected to the 9-pin comm port on a PC.

hgmjr

#### Leccy-Lee

Joined Aug 2, 2008
22
Awesome, why couldn't i find that! Doh

Thanks

#### SgtWookie

Joined Jul 17, 2007
22,210

Joined Oct 21, 2007
43
or just pick up one of the enhanced jdm's off ebay with the zif for $10. Or even a pickit2 for about$35, (works WAY better than any jdm type, also has some usefull tools with it)

Last edited:

#### Leccy-Lee

Joined Aug 2, 2008
22
Thanks, i would buy a made one, but with worldwide shipping and exchange rates it would actually be pretty expensive for me sadly.

#### SgtWookie

Joined Jul 17, 2007
22,210
Anyway, have a look at the link I posted. The circuitry is very similar, also quite simple, but provides more options than the basic JDM 2 does - and will program many PICs that the original JDM 2 won't.

#### Leccy-Lee

Joined Aug 2, 2008
22
I will see if i can the parts for that today Sgt, Wonder if i can rig that up on a breadboard? Do you know if that design works well on ALL serial ports? As i have so far tried LVP programming ICSP which has proved unsuccessful and i think may be because of my PCs serial port?

#### hgmjr

Joined Jan 28, 2005
9,029
I will see if i can the parts for that today Sgt, Wonder if i can rig that up on a breadboard? Do you know if that design works well on ALL serial ports? As i have so far tried LVP programming ICSP which has proved unsuccessful and i think may be because of my PCs serial port?
If TxD, DTR, and RTS do not have more than +7.5V(or -7.5V), this programmer will not work well, especially, with the latest laptop computers that using low power RS232 interface ICs.
The above quote is from the website on the JDM-2. It indicates the criteria that your serial port must conform to in order for the circuit to work.

hgmjr

#### SgtWookie

Joined Jul 17, 2007
22,210
Sure, you can breadboard it - why not?

You'll need to test your serial port's voltages. Laptops probably won't work very well with a JDM-type programmer. Some computer manufacturers "cheap out" on the power supplies, and don't supply enough voltage for the JDM-types to work.

Read all of what he's written; he's built several types, and tells about some of the problems he ran into.

#### Leccy-Lee

Joined Aug 2, 2008
22
Hmm severe frustration driving me mad now!
Built that Multi-Chip as posted by Sgt, Double & Triple checked my breadboard with the schematic, its all fine. Checked my serial port, giving 11v on all correct pins ok.

Tried both Winpic and ic-prog and nothing, not a dickie bird. Nothing happening.

Not sure where to start in fault finding as my electronics knowledge isnt good enough, i mean what voltages should be where in schematic? I get nothing above 3v on the programmer as soon as its connected to PC ? I can see any instructions or functions of the circuit, i mean the LED, when should it be on? If it all, i have no idea what its there for?

Argghh, sorry i try and calm down, but 5 days now and cant continue with my project, just as i need to get the designers firmware onto the chip...

Is it my serial port? My PC settings. I cant take much more.......

#### hgmjr

Joined Jan 28, 2005
9,029
It sounds as though the programming utility you are using is mapping its output to a different serial port than the one you have the programmer connected to. For example, the software may be configured to output to com2 and the port you are connected to is being mapped as com1 by your computer.

How many physical serial port connections do you have on your computer?

Make sure that the programming software is pointing to the com port you intend to use. There should be an "options" menu in the software that allows you to select the com port that is consistent with your computer's com port to which you have the programmer connected.

hgmjr

#### Leccy-Lee

Joined Aug 2, 2008
22
Arghhh, dont you hate it when you suddenly realize what the problem is and kick yourself for not thinking of it 2-3 days ago! Part of me feels completely stupid for missing it, and other half is grateful the problem is solved..

What was it? Well i have a UPS under my desk here, i "had" removed the cables to it, i had disabled the monitoring software for it and thought i covered it. BUT the joys of XP and its background services.. The UPS service was still running and occupying the Com port! GRRRRRR Doh

I was watching TV when i thought of it, rushed in turned off the service and tried Winpic, instantly it detected the PIC and LED flashed away as it read the chip..

Finally..! I feel so deflated.....LOL
(This is why my main computer is my Apple Mac)

Thanks for tips

#### hgmjr

Joined Jan 28, 2005
9,029
I'm so glad you found a solution to your problem. From the tone of your various replies it was beginning to appear that you might have a cardiac arrest before you got it working.

hgmjr