"JDM" pic programmer 2
 

Is anybody using the JDM serial pic programmer?
I built the Pic-Programmer 2 version and I'm debugging
it before pluging in a live pic. (www.jdm.homepage.dk/newpics.htm)

It seems that the VPP (MCLR) pin goes from -.6v to +12.87 volts.
I'm worried that the negative voltage (when it should be zero) might
damage the device being programmed. I tried adding a 1n4148 clamp
diode from MCLR to VSS (Anode to VSS) and that brings the 'zero'
voltage down to -.37v or so.

VDD runs +5.11v (exactly what the Zener diode is rated at). The
+12.87v for vpp is about what it should be given the 8.2v and
5.1v zeners plus the drop through Q1 (and that 8.2v zener might
be the low side, I didn't measure the drop across it).

If the slightly negative voltage on MCLR isn't fatal, I guess
the programmer is good to go. Any ideas?

"Ken Scharf" wrote in message
...
Is anybody using the JDM serial pic programmer?
I built the Pic-Programmer 2 version and I'm debugging
it before pluging in a live pic. (www.jdm.homepage.dk/newpics.htm)

I've used it - it works OK on Win98 but is very unreliable with WinXP, even
with the XP drivers.

Leon
--
Leon Heller, G1HSM
http://www.geocities.com/leon_heller

"Ken Scharf" wrote in message
...
Is anybody using the JDM serial pic programmer?
I built the Pic-Programmer 2 version and I'm debugging
it before pluging in a live pic. (www.jdm.homepage.dk/newpics.htm)

I've used it - it works OK on Win98 but is very unreliable with WinXP, even
with the XP drivers.

Leon
--
Leon Heller, G1HSM
http://www.geocities.com/leon_heller

Leon Heller wrote:
"Ken Scharf" wrote in message
...

Is anybody using the JDM serial pic programmer?
I built the Pic-Programmer 2 version and I'm debugging
it before pluging in a live pic. (www.jdm.homepage.dk/newpics.htm)


I've used it - it works OK on Win98 but is very unreliable with WinXP, even
with the XP drivers.

Leon
I'm going to use it on Linux with PikDev.

Leon Heller wrote:
"Ken Scharf" wrote in message
...

Is anybody using the JDM serial pic programmer?
I built the Pic-Programmer 2 version and I'm debugging
it before pluging in a live pic. (www.jdm.homepage.dk/newpics.htm)


I've used it - it works OK on Win98 but is very unreliable with WinXP, even
with the XP drivers.

Leon
I'm going to use it on Linux with PikDev.

On Sun, 13 Jun 2004 09:42:05 -0400, Ken Scharf hath writ:
Leon Heller wrote:
"Ken Scharf" wrote in message
...

Is anybody using the JDM serial pic programmer?
I built the Pic-Programmer 2 version and I'm debugging
it before pluging in a live pic. (www.jdm.homepage.dk/newpics.htm)

I've used it - it works OK on Win98 but is very unreliable with WinXP, even
with the XP drivers.

I'm going to use it on Linux with PikDev.


Good for you, fella!

Jonesy
--
| Marvin L Jones | jonz | W3DHJ | linux
| Gunnison, Colorado | @ | Jonesy | O/S2 __
| 7,703' -- 2,345m | frontier.net | DM68mn SK

On Sun, 13 Jun 2004 09:42:05 -0400, Ken Scharf hath writ:
Leon Heller wrote:
"Ken Scharf" wrote in message
...

Is anybody using the JDM serial pic programmer?
I built the Pic-Programmer 2 version and I'm debugging
it before pluging in a live pic. (www.jdm.homepage.dk/newpics.htm)

I've used it - it works OK on Win98 but is very unreliable with WinXP, even
with the XP drivers.

I'm going to use it on Linux with PikDev.


Good for you, fella!

Jonesy
--
| Marvin L Jones | jonz | W3DHJ | linux
| Gunnison, Colorado | @ | Jonesy | O/S2 __
| 7,703' -- 2,345m | frontier.net | DM68mn SK

"Ken Scharf" wrote in message
...

diode from MCLR to VSS (Anode to VSS) and that brings the 'zero'
voltage down to -.37v or so.

You may want to check the datasheet for the specific part you are going to
use. the 16F628 datasheet, for example, specifies the absolute minimum
voltage on MCLR at -0.3v. Ditto with the 877 and 84A.

...

"Ken Scharf" wrote in message
...

diode from MCLR to VSS (Anode to VSS) and that brings the 'zero'
voltage down to -.37v or so.

You may want to check the datasheet for the specific part you are going to
use. the 16F628 datasheet, for example, specifies the absolute minimum
voltage on MCLR at -0.3v. Ditto with the 877 and 84A.

...

xpyttl wrote:
"Ken Scharf" wrote in message
...


diode from MCLR to VSS (Anode to VSS) and that brings the 'zero'
voltage down to -.37v or so.


You may want to check the datasheet for the specific part you are going to
use. the 16F628 datasheet, for example, specifies the absolute minimum
voltage on MCLR at -0.3v. Ditto with the 877 and 84A.

..


I could put a germainium or low voltage drop si in series with
the VPP to block the negative voltage all together. That would
somewhat limit the vpp, which might be a problem.