On Sat, 17 Aug 2002, Spehro Pefhany wrote:

>At 04:26 PM 8/17/02 +0100, you wrote:
>
>>If it is mains then you must look at the signal for e.g. 20mS (50Hz) or
>>40mS - I
>>am not sure if the PIC (or any) microprocessors have a facilty for setting
>>integration time...
>
>No current PICs (other than possibly the 14000) uses an integrating A/D
>converter- they are successive-approximation converters. Some of the good
>sigma-delta converters have notch filters that can be set to mains
>frequency, but nothing on the PIC series like that at the moment.
>
>Of course you are free to implement your own converter with the on-board
>capture compare facilities, in which case you can make the period reject
>50 and/or 60Hz ripple (an period of 100msec will reject both).

I was under the impression that all PICs use a C/2C converter which is a
SAR but with integration built in, so only the input hold time must be
respected, after conversion starts the input no longer counts. Am I right
?

Peter

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