Electronic Circuits and Projects Forum

Hello,
I have had a junebug programmer for several months,
and successfully programmed several chips.
Last time I used it, however, I inserted an 8 pin pic 12f675 backwards....

Now I think somethings damaged, but I need some confirmation before
investing in a new programmer.

The tutorial portion of the circuit (18F1320) seems to still function properly.
I can program the 6 LEDs light chaser demo just fine.

However, when I try to use the connector to burn an external chip,
it doesn't seem to stick.

I have dip switches 1,2,3 set to OFF, and the 4,5,6,7,8 set to ON,
(though Ive tried a few combinations).

The puzzling thing is that it seems to program and verify properly,
but then each subsequent verify reads only '0' and fails..

Its as though the burned bits only last a second or so.

Below is the output that leads me to this puzzling conclusion.

Any thoughts appreciated!

Thanks very much,
Rob.

------------

Programming Target (12/16/2009 12:05:07 AM)
PIC12F675 found (Rev 0xB)
Erasing Target
Programming Program Memory (0x0 - 0xE2)
Verifying Program Memory (0x0 - 0xE2)
Programming EEPROM Memory (0x0 - 0x7F)
Verifying EEPROM Memory (0x0 - 0x7F)
Programming User ID Memory
Verifying User ID Memory
Programming Configuration Memory
Verifying Configuration Memory
PICkit 2 Ready

(After the programming is complete, I then do a second 'verify': )

Verifying Target
PIC12F675 found (Rev 0xB)
Verifying Program Memory (0x0 - 0x3FF)
PK2Error0027: Failed verify (Address = 0x0 - Expected Value 0x2811 - Value Read 0x0)
PICkit 2 Ready

-------------------------------------------------------------------------------

A few more notes:

Erase Device (followed by a blank check) always succeed.
(all words are 3FFF)

Programming the device seems to program and verify,
but subsequent reads or verifies return all words: 0000

So it seems I can erase everything to 3FFF, but only program everything to 0000,
which confuses me.

A full erase before programming doesn't help either. (same results, all 0000)


-Rob.

It sounds like you have code protection turned on in the config for the 12F675.

Mike.

Originally Posted by Pommie

It sounds like you have code protection turned on in the config for the 12F675.

Mike.

Good guess, I thought that was it, but my CP is set to off.
(I just tried both settings to be sure).
Also, the burned chips dont do anything in circuit like they used to.

Are you sure that MPLAB is using the config in the code? Goto menu configure->configuration bits and make sure there is a tick in the box at the top.

Mike.

Originally Posted by Pommie

Are you sure that MPLAB is using the config in the code? Goto menu configure->configuration bits and make sure there is a tick in the box at the top.

Mike.

Yep I did. I changed it in the source code, and verified the On/Off status changed in the dialog for configuration bits. I tried both On and Off that way.

Originally Posted by Pommie

The code is verifying correctly before the config is written and so that suggests that somehow the CP bit is getting set in the config. Have you tried using the stand alone PK2 software? You could also try starting a new project and see if that verifies.

Edit, I am assuming that you are not using the chip you placed in backward.

Mike.

Hi.
I haven't tried the stand alone PK2 (didnt know that existed).
My current firmware version on the junebug reports 2.32.0, its thats relevant.

I think Im using one of the other chips, but this particular chip programs fine
on an older newfoundelectronics programmer.

I'll try the stand alone PK2 and/or starting a new project.

Thanks for all the suggestions so far.
Rob

Hm, the standalone pk2 software seems to indicate the verify is successful..
I will investigate further in the morning.
Thanks again.
Rob

Hm.

The standalone PK2 however, has no problem reading or writing at any time.
As well, MPLab seems to erase and program properly (as verified by standalone PK2).
However MPLab *always* reads 0.

I'll test the chip to make sure it actually behaves properly in the circuit.