Re: DDS Module is not functioning


Sorry to have been absent for a spell... have been preparing an exhibit on behalf of our local club for a Maker Faire at the public library this weekend.

Refer to Fig 18 of the AD-9851 datasheet.
To establish serial transfer as the default mode, D0 and D1 should be pulled up to Vcc, and D2 should be grounded.

D0 and D1 are pulled up on the DDS module itself. On the Type I PHSNA board they are not connected to anything.

On the Type I PHSNA board there is a bottom side trace that connects D2 to the ground plane.That trace is marked "D2" and has an "X" across it to show where to cut the trace if parallel mode were desired, but it should be left intact normally. If for some reason that trace has been cut, then the jumper on the DDS module must be in place to establish serial mode.

Jim, N5IB

---In PHSNA@..., <kennnick@...> wrote :

It's been a while since I thought about those jumpers.  I looked at my early notes on putting my unit together.  I started with an AD9850 type board, not sure if it was what we call "type I" or "type II". Anyway, I had this note in my diary:

"There were a couple things I had to correct.  See the view of the DDS board in DDS image.PNG on the site.  The two pin header at the upper left had no shorting jumper -- it needs one to put the board into serial programming mode. '

You definitely need to be in serial mode.  Hope that turns out to be the solution.


Nick, WA5BDU

On Wed, Sep 23, 2015 at 4:03 PM, jpking8@... [PHSNA] <PHSNA@...> wrote:


Thanks very much for the note.

The short answer to the questions you posed in your note is that I have done everything you suggested down to the paragraph discussing the programming jumpers.  And yes, I do have a scope although it is not a memory scope.  I have not previously come across anything in the files concerning how they should be programmed.  If it is there, then I missed it.

I went back to the files and found a file that you posted called DDS Image.png.  It was dated 9/17/2013.  Looking at that image, the top left jumper on my DDS (labeled as J1 on the actual board) is not connected.  J2 (top right on the board) is connected, as is J3 (bottom left).  The remaining jumper on the bottom right of the photo is not connected.

My suspicion is that the J1 jumper on the top left of the board should be connected so that the DDS is in serial mode.  Is this true, and are there any other jumpers that should be connected?  Is this info listed anywhere?


John, W5IDA

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