Re: [Usbpicprog-technical] Help making one. Getting strange results...

[Frans S. <fra...@gm...>]

Hello,

First of all, R13 should be left unmounted, that's why it has no value.
I don't think the ground plane is a problem here, but your VPP seems to
be too low, it should be somewhere around 12V (not 10.7). Could you also
measure it using a multimeter?
You can also try to remove the 12V Zener diode because it might be
causing problems (just leave it open).
Also have a look at the 1uf capacitors, maybe they have quite a high
resistance or their value is not good enough. You can also try 10uF
elcos for that.

I hope this will help you a bit further, anyway - don't hesitate to ask
again if it still doesn't work.

Frans

On 09/01/2010 12:02 AM, RedoX wrote:
>  Hello,
>
> First, I'm a French student, I know my English isn't perfect, but I'll
> try to make it look good. I apologize in advance for my mistakes. So:
>
> I've been trying (fighting ? ^^ ) to make a board of the through-hole
> version of UsbPicProg for almost a week now, but I'm still having a lot
> of problems with it... I got a single side board so, I'm not using the
> ground plane on top of the board, but put some jumpers to join grounds
> on the bottom plane. Maybe that's the cause of all my problems... Your
> opinion on that point ? I don't think that's a problem but am maybe
> wrong too :/
>
> I didn't put R13 on the board because, I didn't know what value
> choosing, and when I tried wit ha 10k Ohms resistor, the results were
> even worse, so I removed it. Am I wrong ?
>
> I'm currently using Archlinux 32bits  with the latest versions
> availables at download (r924 for the firmware).
> IO Test are showing promising results (10.7v on VPP, the others are OK.)
>
> I've checked and checked again my board, but I've got some weird results:
> I have 3 models of PICs: three 12F683, three 16f688 and two 18f2550 (one
> is on the board, the other one wasn't working well when I got It :/).
>
> With the 12f683, my board is working well. (Detect, Read, Erase, Check
> Blank, Program, .. Everything !)
> With the 18f2550, the chip is recognized, can be read, but write on it
> is not possible at all (erasing or programming, same result, no
> changes.) Voltages are OK in all ways: VPP, VDD, ... And the chip isn't
> dead, I'm able to program it with a JDM-like programmer (3-4 resistors,
> and a BS170 to get voltage on Vdd, it's not working without it (while
> the 12f683 is OK without the mosfet...)) with picprog software.
> With the 16f688, even worse... The chip isn't even recognized by the
> software. (I've tried different ones, no results)
>
> Oh, when I'm running the IO tests, board connected to a chip, I get this
> result: When I set Vpp to float and Vdd to 5v, Vpp goes to 4.7v (as Vdd
> really does).
>
> I tried many times, checked every traces, checked almost every single
> solder plot, checked all the transistors, ... Tried version 4.0 stable
> of the software and firmware. No results in any way.
> I've planned to make an other board, cleaner than this one (traces are
> not perfect everywhere) but I wish to make this one working if possible
> as I don't have to much time at the moment...
>
> Do you have any idea ? Met the same problems maybe ?
>
> First, thank for your project, very interesting.
> And Thanks in advance for every little piece of help you may give to me.
>
> ------------------------------------------------------------------------------
> This SF.net Dev2Dev email is sponsored by:
>
> Show off your parallel programming skills.
> Enter the Intel(R) Threading Challenge 2010.
> http://p.sf.net/sfu/intel-thread-sfd
> _______________________________________________
> Usbpicprog-technical mailing list
> Usb...@li...
> https://lists.sourceforge.net/lists/listinfo/usbpicprog-technical
>