Yes...my first PIC...   :-/

First: Read the errata sheet !
(Strange the main data sheet is still "preliminary"!?)

Problems iĞve found not documented in the errata sheet:

1) Upgrade your picstart + to version 7 or later, (lower VPP)
Before i did, my PIC14000JW date code 9752SAT got their code protect bit
set to "illegal" as it reports (whatever that mean) even if i selected not
to program it!   I also upgraded to firmware 1.50.00, that might have
helped too.
(I described the procedure in a posing recently)

2) Date code 9650SAT seem to program correct with elder picstart +, but if
you select HS mode the A/D still keep running on 4MHz internal osc, while
CPU runs at external! (...or if it was the other way around, real fuzzy
anyway, drove me crazy for a while) 



Know, that this is a very cheap single ramp converter.
It needs to be calibrated often against the internal refs, and mchip have
already programmed the calibration data into *EPROM*.

First thing to do when you get the chips is to mark them with different
numbers and read out the calibration data and save it, before you erase them!

Also check how your code handle A/D overflow, and test close-to overflow.
IĞm currently trying to figure out why it sometimes wrap..!?

And use good noise filtering!

Except the above it seem to work as expected.

Carefully select what pin you want to do what, as they are physically very
different; D/A with or without ofset or sum cap, I2C pins with different
drive, D/A ref outputs, compare inputs, etc...

Also the strange D/A converters for onboard comparators have a really weird
construction which also has a S-shape conversion curve, not starting from
zero volts, etc.  Apparently a custom chip from beginning.

(I have made a conversion routine from linear binary to PIC14000 D/A, if
somebody is interested to share code.)

Well, the chip is pretty cheap if we can use all functions, and RAM and ROM
are amongst the largest for a PIC16xx.


And do anybody know what the following mean; 
this text i have found as note in the demo code:

"...there is a possibility that the timer count is captured very shortly
after overflow occurs, resulting in erroneous a/d reading. see application
note for more details. "

How "very shortly", what (might?)happen, what appnote, where???

Please somebody tell!

Regards
/Morgan
        Morgan Olsson                   ph  +46(0)414 70741
        MORGANS REGLERTEKNIK            fax +46(0)414 70331
        H€LLEKS           (in A-Z letters: "HALLEKAS")
        SE-277 35 KIVIK, SWEDEN               mrt@iname.com
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