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Multiple AD7193 connection and programming suggestion

Hi ,I am using MCU and ADC to build a datalogger for a seismometer.I choose Arduino Mega2560 for MCU and Pmod AD5 for ADC.I have found examples made by Annem (github.com/.../AD7193) and I can read voltage data.

The problem now is that the seismometer sensor has three-axis data output (X-axis, Y-axis and Z-axis are all differential).This ADC Module needs to be issued instructions to convert, and I need three ADCs to capture (latch) data at the same time and the MCU only has a SPI set.

So I would like to ask if there is a situation like mine for the circuit connection of multiple ADCs and suggestions for programming. Thanks.



(https://github.com/annem/AD7193) and
[edited by: AlanLee at 3:51 PM (GMT -4) on 23 Jun 2021]
  • Hi,

    We will look into this, I'll contact the product owner and get back to you.

    Regards,

    Andrei

  • Hi, 

    I saw this thread that you may find helpful. 

    (+) How do I interface to multiple AD719x ADCs over the same serial interface ? - Q&A - Precision ADCs - EngineerZone (analog.com)

    In terms of your application requirements. It looks like it is really important to synchronize the ADC. If multiple devices are operated from a common master clock, they can be synchronized so that their data registers are updated simultaneously. You can use the internal clock of one ADC to supply it and to supply 2 other ADCs. A common signal to their SYNC pins synchronizes their operation. This is normally done after each AD7193 has performed its own calibration or has had calibration coefficients loaded into its calibration registers. The conversions from the AD7193s are then synchronized.

    Another important thing to look at is the timing of reading the data register for each ADC. Please take note that when /CS is taken high, the DRDY pin is tri-stated. Therefore, the DRDY pin will not indicate the end of conversion. Since the ADCs will use the same MCLK and the conversion is synchronize monitoring one DRDY pin should work as the conversion time between the other ADCs should be the same. So after the DRDY pin of the first device goes low, read the data register of it then switch to the next device read the data register and so on. Just make sure that your SCLK is fast enough and that you will be able to read the 3 ADC data before the next conversion. 

    Thanks,

    Jellenie