Veneziano Massimo wrote:

> With the collaboration of Steve Marchant I've modified the software
> for
> controlling his low cost PicC84 programmer in order to support the
> PICF84.
>
> Now all modification for the new 16F84 are working properly except for
>
> the BULK ERASE PROGRAM / DATA memory.
> In fact the BULK ERASE commands seems to be without result.
>
> I know that there was a previous message of Vassili Zibarof and a
> corresponding answer of Nigel Goodwin about the same argument.
> Nigel suggested  to add a "Begin Programming" command before the "Bulk
>
> Erase" one.
>
> I've tried and this solution works.. really!
>         There is only a little problem. IT DESTROY THE DEVICE !!
>
> Then at the end this is the situation :
> a) The Microchip Memory Programming Specification description does'n
> work (see paragraph 2.3.1.8 and 2.3.1.9)
> b) After a request to Microchip, at this moments, there are no
> answers.
> c) Adding the 'corridor voice' of inserting a Begin Programming
> command
> doesn't take useful results.
>
> Conclusion : I've implemented two work-around
>
> a) Bulk Erasing Program Memory
> Execute a Disabling Code protection commands (as described on
> paragraph
> 4.1 of the 'F8X Programming specification).
> with the CP bits set to "1" (unprotect).
> In this condition, you are only able to Bulk Erase the Program Memory
> (and not the Data Memory).
>
> b) Bulk Erasing Program & Data Memory
> Protect the device by setting the CP bits to "0", then execute a
> Disabling Code protection commands.
> In this condition, you Bulk Erase both the Program & Data Memory.
>
> As you can see there is no way to Erase the Data Memory only.
>
> Are there other known and verified procedure?
> Does anyone know an official procedure from Microchip?
>
>
> Massimo
> Veneziano

Dear Massimo!

I implemented algorithms exactly as they were given by Nigel Goodvin.
Without his advise I really got stuck with it. When I implemented then
everything started working OK. I tested BULK Erase for data memory as
well as for programm memory - all work. No matter is it code protected
or not.
BTW it is almost impossible to destoy any chip by executing commands.
You'd better check your pover supply circuitry especially that which
applies 12 V to MCLR pin and 5 V connections.

I can help you if you send me your algorithms for check-out. If you do,
please email me directly for I will unsubscribe from piclist for a week
or two due to business trip.

Regards,
Vassili