JDM programmer problem

Hi,
I was wondering if anyone can help me with the following. I'm trying to build the stripboard JDM programmer as described on the reprap site (http://reprap.org/bin/view/Main/StripboardJDM), but when it comes to the tests one of the voltages doesn't match. When I put a multimeter between pins 5 and 14 of the IC socket it's supposed to read 5V but mine goes slowly from 0,19 to 0,31V over a period of about 10 sec. The other tests (5 to 12, 5 to 13 and 5 to 4) measure ok. Can anybody help?

Ron.

Pin 5 is s ground and pin 14 is Vcc or 5VDC. Pin 4 is the programming pin around 12VDC when writing. Usually the Vcc is applied during the program sequence. Do you have a schematic? Voltage is fed to a 7805 to produce 5VDC. I use an old EPIC programmer with a homemade adapter. A good place to start is to check part orientation and placement, then reflow the solder connections.I am looking at the schematic, D2 is a 5.1VDC zener diode. It will maintain 5.1VDC as long as the total wattage isn't exceeded. Zeners are rated in voltage and wattage.The Zener is tied between Vdd and Vss and should maintain a 5.1VDC difference. Make sure that the cathode of D2 is connected to pin 14 through continuity check. The pinouts for the serial port is for the old 25 pin port not the newer 9 pin. pin2 Txd is pin3 on a 9 pin, ground pin 7 is pin 5 , CTS pin5 is pin 8, DTR pin 20 is pin 4 and RTS pin 4 is pin 7 on a 9 pin.

This is a link for pin assignments, [www.interfacebus.com]. Are using a 9 pin,(likely) or an older 25 pin?

Edited 1 time(s). Last edit at 07/25/2007 08:57PM by englewood.

Hello englewood, thanks for your reply and the info.
I am using a 9 pin connector using the numbers that Simon (I think) wrote in the text, not the ones on the schematic picture.
TxD to 3
GND to 5
CTS to 8
DTR to 4 and
RTS to 7

test voltages:
pins 5 and 13: 0,1V - Enable Data Out - 6,91V
pins 5 and 12: 0,2V - Enable Clock - 5,83V
pins 5 and 4: 0,45V - Enable MCLR - 13,57V

This afternoon I just got myself one of these breadboard thingies, so i might just take the stripboard apart again and make it on that. I will check the continuity between D2 and pin 14 first though. (I'm not at home right now)

thanks again

Ron

I built the optosensor on a breadboard first to test it,(I used a different sensor than in the BOM). breadboarding is a great idea before soldering. It does give the orientation on the strip board picture. I think a note should be included about the 25 and 9 pin RS232. I can't see where it could read the PIC, no RX is used! I guess it is a one way programmer, no verify or read.

Well it does say "Note: This is a preliminary design and has not yet been tested" at the top of the page of that JDM programmer, so I knew I could expect some problems :-) I Didn't realize that you can't verify with it, and I don't really like that. I'm not really having much luck with this PIC programming business. Originally I bought this one... [www.velleman.be] which promised to deliver everything i ever wanted and more, but it gave me some sort of configuration error when i tried to write the program to the PIC (can't remember the exact wording of the errors and I am still not at home :-) but at least that one would have been able to verify.

My electronic skills are quite limited. I've been soldering up little schematics that I've come across for more than 20 years now, but I've never been educated on the subject and most of the time I dont really know why what does what, but I get along with that fine (most of the time).

Ron

> I Didn't realize that you
> can't verify with it, and I don't really like
> that.

I don't think that that is true. I built one and as big a dog of a thing as it was it would verify. Mind, I wasn't satisfied with it at all and eventually bought a USB one from melabs.

[www.melabs.com]

That let me stop worrying whether that stupid JDM design was going to get enough voltage out of the RS-232 port to actually program a pic more than a few times.

i've been using this one for a while now, and it works great (and is cheap to boot.)

[microcontrollershop.com]

JDM designs can read and verify the PIC just fine, they just don't use the RX pin for it, they use one of the control pins, CTS I think. They also don't use the TX pin for sending the data, it's just used to generate the programming voltage I think.

That is interesting. I always thought the control signals sent little data, Device ready to read and such not lots of bytes. The 5vdc is maintained by the zener diode though and a string of zeros maintains the +12VDC for the zener to regulate to 5VDC. I have an old epic programmer from 1996. I just built an adapter for it and it works great. Unfortunately it uses a parallel port, so I can only use it on my desktop or old laptop. I know you have to put Vpp on pin 4 to enable programming, (around 12VDC). I am going to look at that schematic closely.

I can confirm that a JDM-style programmer (Olimex PIC-PG2 from SparkFun -- inexpensive, but avoided the need to build it myself!) can verify your PIC programming just fine. It took me testing on a few PCs before I found one whose serial port works with it, but once I found the right PC (our family Windows PC, a 3 year old Dell Dimension!), it has worked fine for me.

To avoid the "needs a good quality serial port" issue, a PIC-PG3 is about US$10 more and uses a parallel port instead. I think this is what Zach uses.

The Velleman K8076 design uses an external power supply, so it should also avoid the "needs a good quality serial port" issue.

Jonathan

JDM designs can read and verify the PIC just fine, they just don't use the RX pin for it, they use one of the control pins, CTS I think. They also don't use the TX pin for sending the data, it's just used to generate the programming voltage I think

i have problem with jdm programmer i dont know pin for d-type 9 pin connector connection so please kindly help me ,