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DAC7750 SPI reading back issue question?

Joel Li
Intellectual 2165 points
Other Parts Discussed in Thread: DAC7750

Hi team,

Here is a question from a customer when using DAC7750. When we are sending read command and reading back registers, the returned value is always the same as what we send:

Channel 1: SCLK;  Channel 2: SDO;  Channel 3: Latch;  Channel 4: DIN. Please ignore the amplitude difference (channel 3 probe is 10x gain setting).

As you can see, when sending 24 bit: 0x 02 00 0B to read configuration register, the returned value is same as what we send: 0x 02 00 0B. And we have tried to read different registers, the situation is same.  

what could be the reason?

Thank you!

Joel Li

joel-li@ti.com

  • 0
    TI__Mastermind 46290 points

    Joel,

    Could you provide the intended register configuration for the device? Is there any chance daisy-chain is enabled? If I recall correctly the device shouldn't have anything but 0's on the SDO pin unless a valid read command sequence is issued. If daisy-chain is enabled the device is just clocking out data on SDO as it should for a daisy-chain configuration.

    Otherwise the edges / frames seem to be okay.