Bulk Write to AD5370 via SPI

  1. Based on what I understood from https://www.analog.com/media/en/technical-documentation/data-sheets/AD5370.pdf SPI Write Mode on page 21. I am attempting to write to AD5370 at the maximum speed possible. According to the documentation, it states that. The SYNC has to be pulled high after every 24 bits written. This means each 16-bit word to each channel requires a sync pulse. Is there a way to make this faster without the sync pulse? So writing a frame for 40 channels require 40 sync pulses?
  2. Why do we have two registers A and B on the board? If we can use only one at a time? for all channels? Is there a design element that I didn't understand about this board?

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    •  Analog Employees 
    on Nov 5, 2020 10:54 AM 2 months ago

    Hi, 

    May I know what type of application will you use the AD5370 for? Is there a tight spec on the write time? In the case of AD5370, SYNC is required after every 24clock cycles to ensure that the data won't be corrupted and written to the correct register. 

    writing a frame for 40channels would require 39  sync pulses since the last sync should remain high if there are no other data to be sent in the serial bus. 

    Having two registers allows the holding of 2 sets of output settings for each channel. Let me clear up that each channel can be configured as to which input register will it take its data from. This could be useful in applications where there would be 2 sets of output values. Switching to the second set of output data would take less number of SPI word transactions compared to writing to all 40 channels individually.

    Let me know if I have answered your questions.

    Best regards

    Ian