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AD7794, when CS is left LOW during power up and then after say 10mSec, it goes HIGH, does it retains 4 wire SPI?

Question asked by riscy0000 on Oct 27, 2017
Latest reply on Oct 27, 2017 by JellenieR

When /CS is left LOW during power up for say 10mSec and then goes HIGH, how this impact the SPI does it revert back to 4 wire SPI mode or stuck 3 wire SPI MODE.

 

I was trying to use AD7794CS (when LOW) to turn ON the +5V PSU from a linear regulator and then make short HIGH LOW pulse (no impact on lin reg due to caps) and then use SPI to configure the device and initiate capture. When done AD7794 set to standby mode and turn off +5V power. 

 

The Digitial side remains powered +3V3S all the way.

The analogue power (+5VADC) turns ON/OFF to save power (from the linear regulator). 

 

Can you see issue what I'm doing?

 

R. 

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