My frequency is correct, if the board boots.
In that case what you are doing cannot be too far wrong.
I'm confused about the reset status. Figure 7 in the AD9850 datasheet shows the reset pin pulled high to perform reset.
Is the reset pin kept low for normal operation? I've tried it in both states.
Yes, pin 22 of the AD9850 is high for reset, and low for normal operation.
There are two clocks working in the AD9850: The first clock is the oscillator (mine is 125mhz) that operates the AD9850. The second clock is the clock pin of the controller which operates the W_CLK, AD pin 7, that passes in the data.
On my program I only pulse the controller clock if I am passing in data.
OK
I've tried my program in refresh and single command mode. I don't see any difference.
I wondered if the program was running away with itself into the realms of fantasy and scribbling silly data to the AD9850.
I've operated the board in both serial data transfer and parallel mode. The same problem exists in each.
I have never tried parallel programming.
My problems are consistent across all four boards I own. I wonder if I have a bad batch.
When I bought my boards I wondered if they would be some cheap knock-off thing, but all three have worked correctly for me.
I started many years ago with a pukka Analog Devices chip and the Chinese modules worked exactly the same with the same software.
The only things I can suggest without seeing the thing is to:
Wait untill the power is stable before initialising the DDS.
Ensure that the supplies are well decoupled.
If you are doing a serial load of the 40 bit control word, ensure that pins 3 and 4 of the AD9850 are pulled up to 5v and that pin 2 is pulled down to 0v.
Pulse W_CLK
Pulse FQ_UD
The AD9850 should now be correctly in serial load mode.
Sorry if I am telling you things which you know already.
Its amazing. I'm 60 Km from the Pacific ocean and you're not far from the Atlantic and the North Sea. Distance knows no bounds.
I am about 16km from the North Sea, not too sure about the Atlantic, probably a good 4 or 5 hours drive and then I would be looking out at the Western Isles rather than the wide open Atlantic.