Gerhard Fiedler wrote:
>
> I wanted to put my _own_ data in OTP EPROM locations (no reset vectors, no
> chip configurations or whatever) -- but data I only know after having
> loaded the PIC with some program to get me this data. That's why I'd have
> to do this in a second programming run. Tjaart confirmed that it might work
> as intended.
>
> But probably I won't check it really out, because some further
> investigation led me to believe that I need more than 8bit ADC resolution,
> so I'll use a 16f84 (with a LTC1288 ADC) instead of the intended 16c711 --
> and then I have an on-chip EEPROM.
>
> (But still I think this is something useful and that I'll use it sooner or
> later; often you have to calibrate an ADC or DAC, but you just do it
> _once_, so that the results can very good be stored in OTP memory. And if
> you have a little spare room for the routine in your program space, that's
> the ideal place to put it...)
>
> Thanks for the thoughts :-)

Here's another one :) We are going to write serial numbers in all the
PICs we
program. Because Mchip won't let us read the chip ID from within the PIC
software, we decided to do it in the ROM. In the software, there is a
lookup
table filled with retlw FFs (unprogrammed) During the manufacturing
process, the
serial number is written in this space as a set number of retlw
instructions. The
PIC can read this and we can identify each individual chip made by us.

--
Friendly Regards

Tjaart van der Walt
mailto:tjaart@wasp.co.za
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