HFU HF Underground
Technical Topics => The RF Workbench => Topic started by: JimIO on December 05, 2019, 0009 UTC
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I've been looking at directly programming the AD9833 chip by SPI without
using a microcontroller. Still a work in progress. Here are some links you
may find interesting.
https://www.analog.com/media/en/technical-documentation/data-sheets/AD9833.pdf
https://www.analog.com/media/en/technical-documentation/application-notes/AN-1070.pdf
https://www.analog.com/en/design-center/design-tools-and-calculators.html
https://www.analog.com/designtools/en/simdds/?part=AD9833&fin=25M&mult=1&ftw=1
https://www.nongnu.org/avrdude/
https://www.nongnu.org/avrdude/user-manual/
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I have a USBASP USBISP adapter with 10 Pin Cable:
https://www.ebay.com/itm/262130708242
I figuered out how to talk to it with:
avrdude -c usbasp -P usb -v -t -F -p t4
Next step is get out the soldering iron and wire up the AD9833 module:
https://www.ebay.com/itm/142719447732
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Why NOT use a micro?
I use an attiny45, and have 'single frequency' SW or a 'tunable' version.
However I cant disclose the code as it's used in my products using the same AD9833 PCBs from CH.
Simplest implementation around!
Shame it doesnt put out a decent 5V squarewave but rather a rather puny 100mV sine and need some serious filtering and amplification BTW.
Str.
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One reason to not use a microcontroller is that I don't like the arduino IDE.
If what I'm trying to do now does not work I may try using the USBASP as a controller. It has an ATmeg8 chip on it. Also I found this tonight:
https://blog.podkalicki.com/how-to-compile-and-burn-the-code-to-avr-chip-on-linuxmacosxwindows/
I like command line stuff!
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I don't like SW at all!
I got someone to write it for me.
I'm sticking to hardware!
Str.
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Several years ago I played around with the CY22150: https://hfunderground.com/blog/?p=215
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One reason to not use a microcontroller is that I don't like the arduino IDE.
If what I'm trying to do now does not work I may try using the USBASP as a controller. It has an ATmeg8 chip on it. Also I found this tonight:
https://blog.podkalicki.com/how-to-compile-and-burn-the-code-to-avr-chip-on-linuxmacosxwindows/
I like command line stuff!
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I think you have to use a micro, whether you get a board that comes with one pre-programmed or not.
If you like command line, what I would recommend is writing some serial control code that translates between the serial and SPI. This way you can develop your own "command line" that works exactly how you want. If you buy something, it is unlikely to meet your exact needs. You can then use a serial to USB and a terminal such as Realterm.
It's not that hard to do. You can just read strings from the port and then do a bunch of IFs or a switch. First split the string by space. Send the first part through the switch statement, and then use the rest for your parameters.
I don't like Arduino much either. I use MikroC Pro for PIC. I use PIC chips for all my stuff, but they make software for Atmel as well.
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...see my last post.
BTW, why did you choose the AD9833? I've never really heard of it. Is it any better than the AD9850 modules?
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I hate programming as well, but have warmed up to the Arduino IDE. I like it much more than the PIC stuff we had in college a decade ago. The AVR's seem to be more robust as well. I've had a number of PIC devices randomly fail over the years, yet only one of the AVR's...who knows.
As far as the AD9833, I suspect cost was a determining factor, not performance.
+-RH
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9833 is available very cheap from CH on a PCB with a clock etc, just check eBay.
Sure only goes upto 12.5MHz, less in reality.
However with the implementation I use with an attiny45 the whole circuit to generate any frequency on 2 stacked PCBs 1/2" sq.
The 9850 will go way higher and also has opposing squarewave o/ps most useful for push pull class E as they will switch drivers directly.
I guess a good 'modern' solution for upto 30MHz would be the 9834 again available from CH.
Str.
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"9833 is available very cheap from CH on a PCB with a clock etc, just check eBay."
Every electronics hobbyist should know about ebay. 8)
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