AD9106:How to use the RAM pattern

Hi LiuZhenrong ,

Thank you for using AD9106.

Please help to share your plan settings and target output.  Appreciate if you can share your SPI Dump as well.

Thanks and kind regards,

Alex

Hi Alex

Thank you for your reply. I have already found the answer to that question from other sources.

I now have another question. In the datasheet, the recommended initialization sequence for the AD9106 is as follows:

1. Set CS, RESET, and TRIGGER to high.

2. Configure the SPI port.

3. Assert RESET by pulsing low then high.

4. Write the necessary registers.

5. Update the RUN and RAMUPDATE bits.

6. Set TRIGGER to low.

What I would like to know is: after following the above steps to start the DDS, if I need to make some changes, such as modifying the frequency via DDSTW or the phase via DDSPW, is it necessary to set TRIGGER back to high before modifying the registers? Is it possible to modify the registers while keeping RUN bit = 1 and TRIGGER = low, and then update the operation using the RAMUPDATE bit? By the way, my design only uses continuous sine waves and DAC constant output.

I am currently in the circuit design phase and do not have an evaluation board on hand, so I cannot verify this. However, I would like to understand this feature in order to finalize my circuit design.

Thank you.

Hi LiuZhenrong ,

You do not need to set TRIGGER back to high before modifying registers. You can write to DDSTW, DDSPW, or other registers while keeping RUN = 1 and TRIGGER = low, because all SPI writes go to shadow registers and can be done at any time. After writing, asserting RAMUPDATE will arm the transfer of these values to the active registers. 

Thanks and kind regards,

Alex