Very very strange problem on 18F1320. The µC

[Mathy]

Hello everybody !

I have a very strange problem with a little board. I use a 18F1320 and with the attached program, I can download the .hex into the 18F1320 only one time ( I use a mikroelektronika programmer ).
The second time, the programmer doesn't recognize the 18F1320. Impossible to program !

The only thing I change is the TMR1 Interrupt I disabled.
Before this strange problem, I have programmed many times this 18F1320.
I test with a second board and Im sure the hard is OK.
If I take an other 18F1320...same problem. The first time is OK but the second.....
The problem come from my attached program but where ?

It is possible to destruct a PIC by software ?
If somebody want to test, you have to prepare many 18F1320

Thank you so much !

[tiny]

On the Konfiguration page the Master Clear is disabled. This configuration brings the problem, that you can one time program the chip, the second programming faild. Set the Master Clear to enabled and I think this works fine.
tiny

[Mathy]

Thank you tiny,

but I think the problem doesn't come from the MCLR pin because before using the TMR1 interrupt, the master clear was already disabled and I programmed many many times !

[tiny]

OK, I had a timer problem also with timer 1 under Flowcode 3, defined as own Interrupt. There the same problem appeared and at that time I have found no solution. I had changed the program routine on timer 0 and had built up the macro with several routines. Maybe can help here Benj or Steve.

[tiny]

Hi Mathy,
I have built up an easy circuit with timer 0 and timer 1 and have tested in each case for PIC16F876 and PIC18F2680. Also functions with repeated one program easily. Then I have changed your program on a PIC18F2680 and have programmed several times alternately with the timer program, also without problems. I use MPLAB ICD2 of Microchip with direct connection in my circuits or Testboards. Unfortunately, I cannot test a PIC18F1320, has at disposal nobody.

tiny

[Benj]

Hello,

Thats very odd indeed. I cant see any reason why disabling the timer 1 interrupt should cause the device to stop programming. The timer 1 peripheral has links to the Watchdog and the PWM but this should have no impact on the device memory or reprogrammability.

Your configuration also all looks ok to me.

The internal MCLR can sometimes cause problems but as you said before it was working well until you disabled the interrupt so it is unlikely causing a problem now.

It may be worth putting the EB006 into RC mode before programming as this can sometimes help to unbrick a damaged PICmicro.

The internal external switch over mode could also be disabled in the configuration as a test.

Other then that it may be worth asking microchip directly if they know what the problem is with these devices. Could be that there is a silicone error on this device as this does happen, this is however fairly unlikely. Whats more likely is that the device failed for some reason just as you happened to disable the timer. Is there anything strange about your PSU etc?

[Steve]

We cannot offer much support for the Microelectronica board and programmer because we do not have access to their hardware.