AnsweredAssumed Answered

AD7606 MISO Doesn't Work

Question asked by hzmaks on Mar 18, 2014
Latest reply on Apr 24, 2014 by hzmaks

Hi,

 

I have 2 board. Both in 2 boards there is AD7606 ADC.

 

AD7606 at first board is work well. Its AVCC 5V and Vdrive pin is 3.3V.

 

At second board, there is same design with first board. There is no probability to doesn't work. But it doesn't work.

 

AVCC and Vdrive is 5V_ISO. 5V_ISO is converted from 5V at the first board. I use Murata Isolated DC-DC converter for this. The start-up time of module is 0.9 ms.

Also I use ADUM to isolate CE, CLK, CONVST, BUSY, DOUTA and DOUTB signals. (I check the signal at in and out pins at ADUM, I see the CLK, CE, CONVST, BUSY signal properly.)


* When I drive the ADC same code like in first board, I see CE, CLK, CONVSTA-B, BUSY, RESET on scope. But I can't see DOUTA and DOUTB signals. They are always low.

* After that, I pulled-up the DOUTA and DOUTB to 5V. And test ADC again. This time, I see Clock signal (CLK signal) at DOUTA and DOUTB.

 

I checked the ser/byte selection pin, it is pulled-up with 4.7K resistor to 5V_ISO.

STBY pin s pulled-up with 4.7K resistor to 5V_ISO.

 

Is there any idea no MISO out and DOUT pins?

Thanks and BR.

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