AnsweredAssumed Answered

AD9837 setup problem

Question asked by thelamnguyen on Jul 5, 2018

Hello all engineers,

 

I'm currently testing AD9837 evaluation board in conjunction with an evaluation board C8051F340 from Silabs. I've looked around and read the AD application not AN-1070 to find the solution to my problem but still struggle with it so, I'm asking you all here if you can help shed some light on my problem.

Here is what I understand about the write sequence to the AD9837 device:

  • Send 0x2100 (Reset device and set bit D13 to 1)
  • Send 0x1234 (write to LSB frequency register 0)
  • Send 0x5678 (write to MSB frequency register 0)
  • Send 0x4321 (write to LSB frequency register 1)
  • Send 0x8765 (write to MSB frequency register 1)
  • Send 0xC000 (write to phase 0 register)
  • Send 0xE000 (write to phase 1 register)
  • Send 0x2000 (Exit reset)

Ok, my question here is every time I need to send a 16 bit command to the AD9837 device, I have to send 2 bytes (8-bit for each write). However, which byte I need to send first? Lower byte or the higher byte need to be sent first? 

I've tried but didn't have any lucks with both ways. The device don't seem to behave the way it should.

Please assist if you can, any help/inputs would be greatly appreciated. Thanks and have a wonderful day.

 

Best Regards,

TLN

 

PS: The attached file is the code to config the device. Please take a look if you can and tell me where I did wrong. Thanks

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