piclist 2001\01\31\083100a >
Thread: verifying from vddmin to vddmax & bootloading
face BY : mike.....@@spam@whitewing.co.uk

On Wed, 31 Jan 2001 10:12:09 +0000, you wrote:

>the recent thread on 16f877 programming inspired a little musing:
>'decent' programming hardware apparently verifies a part over a range of Vdd values to ensure the
>bits have been set correctly.
I believe this is only the case for OTP parts
>it would seem that using a bootloader with a flash part the bits are only be verified at the current
>possible conclusions:
>(1) a bootloaded part may be less reliable than a 'hardware programmed' part.
>(2) there's no need to do the whole vdd range thing with flash - it's a technique that's only
>meaningful for eprom type memory cells.
This would be a reasonable assumption. The flash write self-timing
will probably ensure sufficient overprogramming to cover all voltage
>(3) there's some cunning circuitry inside the flash parts that does actually ram the voltage supply
>down (and up ?) to the extents of legal vdd during the verify.
Nope - this would cost money to add (die area)

>any of you have anything _other_ than anecdotal evidence to support any of these possible
>conclusions, or indeed some other conclusion i have missed ?
When programmed via bootloader, it's likely that this will be at the
normal application Vdd. A 'socket' programmer doesn't know what
voltage  the chip will run at, and it's therefore more important to
verify the whole range.

http://www.piclist.com hint: To leave the PICList

<8frf7tgvc1dfln8aqgdra4olfl3lpmst3f@4ax.com> quoted-printable

In reply to: <802569E5.00384569.00@buffer1.HQ.quantel>
See also: www.piclist.com/techref/power/decouple.htm?key=vdd
Reply You must be a member of the piclist mailing list (not only a www.piclist.com member) to post to the piclist. This form requires JavaScript and a browser/email client that can handle form mailto: posts.
Subject (change) verifying from vddmin to vddmax & bootloading

month overview.

new search...