PIC16F877 - AD7730 SPI Connection Problem

Started by Triontech Technology September 14, 2005
Hi,
 
I wonder if any of you guys could help me out a bit. I am trying to hook the PIC16F877 to AD7730 (ADC loadcell controller for Analog Dev) thru SPI.
 
I set the AD7730 to work in continuous conversion mode, monitoring the RDY line once data has been updated.
 
I am having problem getting the PIC to communicate with AD7730. Sometimes I got it to work but most of the time is just doesn't work.
 
I suspect it is the polarity of the CLK that is giving problem. I am using CKP = 0 and CKE = 0 to write to AD7730.
 
I am using CCS5X C Compiler (free version) to write my software.
 
Hope you guys can help me on this. Thanks in advance
 
regards,
Lai Chun Mun

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> Hi,
>
> I wonder if any of you guys could help me out a bit. I am trying
to hook the PIC16F877 to AD7730 (ADC loadcell controller for Analog
Dev) thru SPI.
>
> I set the AD7730 to work in continuous conversion mode, monitoring
the RDY line once data has been updated.
>
> I am having problem getting the PIC to communicate with AD7730.
Sometimes I got it to work but most of the time is just doesn't work.
>
> I suspect it is the polarity of the CLK that is giving problem. I
am using CKP = 0 and CKE = 0 to write to AD7730.
>
> I am using CCS5X C Compiler (free version) to write my software.
>
> Hope you guys can help me on this. Thanks in advance
>
> regards,
> Lai Chun Mun

Some ADC's with SPI interfaces (atleast the ones i've worked with)
can get locked up if bad data is sent so to reset them you have to
send
a string of one bits(the ADS7870 needed 32<48?> to reset). I don't
know if the AD7730 is the same though.