Matrix user forums

Hi. My USB Lite Programmer works fine with 16F88, but it won't work with 16F628 or 16F628A (I've tried both).

When I try autodetecting chip or burning to one of these PICs, the software stops responding, and I can't do anything. If I pull out the cable, it starts responding again, but gives the message: "External exception C0000029."

It's not the jumper, because I've changed it to the other setting.

The about-screen says my PPP version is 3.4.7.19, and my firmware version is 2.

Does anyone know what the problem is?

Hi Metalicat,

There is a problem to do with LVP being disabled on chips.

If the Chips have had LVP (Low Voltage Programming) disabled then they will not be detected in the Lite programmer.
The chips need to be LVP enabled. This is the default state for most LVP chips when fresh from the manufacturer.
However the chips may have LVP disabled if used in other programmers, which will then stop them detecting in the Lite programmer.
You will need access to another programmer (presumably the one that disabled LVP on the chips) to put them in and enable LVP on them.
Unfortuantely you can not re-enable LVP on the Lite programmer.


To compound the problem PPP does not respond as it can not find the non-LVP chip.
We are currently looking into if this is the case in all versions of PPP, or just the latest ones.

We will post any updates on this, and details of the PPP fix (to at least report the error and not lock up) once we have it.

You were right! All the other chips had been previously used in non-low voltage programmers. I ordered some "fresh", usused devices, and they were detected just fine.

I have now tried 16F88, 16F648A and 16F628, and all have been deteced as they should.

Thanks a lot! =)