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Problem reading AD7682

Question asked by joukem on Mar 15, 2012
Latest reply on Mar 19, 2012 by maithil

Hello,

 

I'm trying to read out an AD7682 with a LPC1113/301, but I only read back zero's. I'm want to use the internal reference of 2V5 (supply is 3.0V), but when measuring this on the REFIN pin it's almost 0V. When trying to read back the CFG register, the AD7682 gives back the data I've sent (and it seems correct).

 

I'm using the following design:

Fail_SchematicAD7682.png

The following communication occured when trying to read out the ADC values (channel 1 (yellow) is DIN, 2 (purple) is SDO, 3 (cyan) is SCK and 4 (green) is CNV).

 

Fail_AdcReadOut_Multiple.png

Fail_AdcReadOut_Send.png

Fail_AdcReadOut_ReadBack.png

Does anyone has an idea what I'm missing or doing wrong?

 

Thanks in advance,

 

Jouke

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