Dear Jan-Erik,

1. of course I looked at the data sheet first, but ofter there are
additional information. It's like the data for eeprom: When reading the dat=
a
sheet saying 100000 changes possible and data retention years and years -
it's just not true !

2. Well, seems I have to live with that 5V. Software is protected, so bulk
erase is needed....

3. No bad design, but sealing the whole electronics after production, just
leaving the edge connector for ICSP...

Regards

Peter


-----Urspr=FCngliche Nachricht-----
Von: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] Im Auftrag vo=
n
Jan-Erik Soderholm
Gesendet: Montag, 21. Februar 2011 12:18
An: Microcontroller discussion list - Public.
Betreff: Re: [PIC] ICSP with Vdd<>5V

IB Peter Feucht wrote 2011-02-21 09:02:

> When looking at several application notes...

The specifik datashet and the "Memory Programming Specification"
for the PIC12F519 are the docs to read.

> ...I only found the possibility of
> ICSP with Vdd=3D5V! Do I miss something?...

As far as I can see, it as "as usual". The "Bulk Erase" needs at least 4.5 =
V
(param VDDOK in the Mem Prog Spec). The datashet says "The Flash data memor=
y
is readable and writable during normal operation (full VDD range)."

Most programmers does a "bulk erase" as part of the programming cycle (and =
a
bulk erase is the only way I know of to re-program a protected device).

> My ICSP hardware is a PICStart+ (I
> love it!) with a self made adapter.
>
> To let you know: In series production the PIC is flashed with Vdd=3D5V=20
> when the other part is still not attached. And it is much work to
disassemble it!
>

Bad design ?

> My questions:
>
> Is there a possibility to make flashing with Vdd=3D3,0V on a 12F519?
>

Depends on what "flashing" is. Not "Bulk Erase", of course.

> If possible at all, is it reliable, to just use a voltage divider for=20
> Vdd, ICSPCLK and ICSPDAT? I assume I have to keep the Vpp at those=20
> 12,5V (which makes no problem in my case)
>
> Thanks for help and best regards
>
> Peter
>
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