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ADC data out issue

Question asked by vinodkaruvat on Oct 13, 2017
Latest reply on Oct 31, 2017 by Gnib

Hello,

 

I am using AD7949 ADC. It is interfaced to a Delfino MCU. I am using a 14MHz clock (it is the minimum clock recommended in the datasheet). Initially I was sending a very lock clock. There is no data from the ADC (MISO). So, I increased it to 14MHz. Still no luck.

 

Clock and MOSI.

 

The above image shows clock (14 cycles) and data sent from the MCU (in MOSI).

 

CLK and CNV.

 

The above image shows clock and CNV.

 

CLK and MISO.

 

Clock and MISO. Yellow is clock while blue is MISO. Miso line shows some faint activity. The next figure shows an AC coupled MISO signal.

 

CLK and MISO (AC mode).

 

I probed the reference pin. It does not show any voltage. I am supposed to get 2.5V as it is done so via CFG register.

How can this be explained ? I am quite confused with the shown waveform. Any help is appreciated.

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