AD9850 Users

[Mikebits]

While trying to locate info on the AD9833, I came across this really nifty App note that will interest experimenters working with the AD9850. Well I hope you do find it useful.
https://www.analog.com/media/en/technical-documentation/application-notes/AN-557.pdf

 

[JimB]

Yes Mike, I have seen that before.
I first saw it in RadCom when it was first published.
I used his technique of mounting the 9850 into a 28 pin DIL header on the first one I used.

The same author wrote a series of articles describing various amateur radio applications using the 16C84. Yes it was that long ago, 20 years. Where does the time go when you are having fun?
Anyway, his key feature was squeezing the maximum out of the PIC by using a lot of multiplexed I/O.
I remember a comment by Blue Room Bill about PIC I/O multiplexing:
"If you need that much I/O, you need a bigger PIC"
An idea which I very much agree with.

I do not want to detract from the info in the application note, but if you were doing it again today, you would do quite a few things differently.

JimB

 

[Mikebits]

Jim, go ahead and delete the post if you think it is too outdated.

 

[Les Jones]

There still seems to be interest in using this chip. There was a recent thread by someone that was building a synthesiser using the 9850. He was having trouble programming the PIC.
This is the thread. https://www.electro-tech-online.com...-needed-for-micro-pro-k150-programmer.147207/

Les.

 

[JimB]

Jim, go ahead and delete the post if you think it is too outdated.

No, not at all!
Just because I have seen it before, that does not mean that others cannot learn from it.

JimB

 

[jpanhalt]

That chip still is included on inexpensive DDS modules from China (e.g., eBay or Banggood). It works well and will give fractional Hz. I posted a little demo code for it here: https://www.electro-tech-online.com/articles/demo-assembly-code-ad9850-dds-signal-generator.755/

John

 

[BobW]

I hadn't see that app note. Thanks for posting the link. I just picked up a cheap AD9851 based DDS module off Ebay. Different chip, but very little difference in operation. So, that app note should still be applicable.

 

[Mikebits]

That chip still is included on inexpensive DDS modules from China (e.g., eBay or Banggood). It works well and will give fractional Hz. I posted a little demo code for it here: https://www.electro-tech-online.com/articles/demo-assembly-code-ad9850-dds-signal-generator.755/

John

I knew I should re learn Assembly. The last time I learned and used Assembly was for the 80C48 CPU, back around 198ish