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AD719x communication problem

Question asked by asadi.siyavash on Jan 26, 2014
Latest reply on Feb 3, 2014 by ChrisD.Rama

Hi,

With your engineers guides, I decided to use AD7190, 24bit ADC as Analog to digital convertor for my high precision Accelerometer, I designed my schematic and PCB. my accelerometer work but I have problem for communication with AD7190.

I want to communicate whit AD7190 by a spartan3 FPGA .for this work I first initialize AD7190 by sent to Sclk pin about 48 pulse of Sclk and hold Din high. after this work I write to communication register 0x28 for communicate whit GPOCON register, and then write 0x3F to set P0,P1,P2 but it doesn't work.


Each byte I wrote to communication register I saw no reaction from ADC for example DOUT Pin was always 0.5volt, even when I write to communication register for sending data, for example when I write status register to read it still is 0.5volt!

In hardware test I saw that SYNC Pin isn't high however, as it mention in datasheet that it internally pullup, is it need an external pullup? Can it be an issue?

Is it true that Dout must be high after power up ADC?

how can ensure that AD7190 was damaged or not ?

Also,I try my codes with PIC Micro controller and I saw same results,

I attached my C code and board wires.

 

The board wires connections make available to the AD7190 this signal levels:

AVdd=5V

DVdd=3.3V

AGND=DGND=0V

REFIN1(+)=5V

REFIN1(-)=0V

AINCOM=0V

AIN1=Analog output of Accelerometer X position

AIN2=Analog output of Accelerometer Y position

SCLK/DIN high=3.3V

SCLK/DIN low=0V

 

any help would be greatly appreciated,

all the best,

Siyavash. 

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