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Scott Harris
05-10-2008, 03:24 AM
I need to read a single ADC channel at about 100 kHZ and then send that value to seven other cogs that will do a few fixed point operations and compute seven new values to send to seven other DACs. So the loop is: read one voltage->compute seven values->send them out on seven DAC channels->repeat as fast as possible.

This is a closed loop control problem. Does this sound reasonable on a propeller? Does anyone have suggestion for appropriate ADC and DAC chips? I suspect 10 bits would be fine.

The application I'm working on is typically accomplished with DSP chips, but I'm wondering if something like this can be done on a propeller.

If 100 kHz is too fast, what sort of rates do you think I could accomplish?

Thanks,
-Scott

Mike Green
05-10-2008, 04:54 AM
In assembly language, the Propeller is certainly capable of handling the data rate involved. If you limit the ADC and DAC to 8 or 9 bits, the Propeller can even do the ADC and DAC by itself. Download the application note on the built-in counters (www.parallax.com/Portals/0/Downloads/appnt/prop/AN001-PropellerCountersv1.1.zip (http://www.parallax.com/Portals/0/Downloads/appnt/prop/AN001-PropellerCountersv1.1.zip)) and look at the comments in the ADC.spin object.

BTX
05-10-2008, 05:48 AM
Hi Scott !
Are you trying to do an audio reverb ?

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Regards.

Alberto.

Scott Harris
05-10-2008, 06:47 AM
Nope. I'm trying to build a control loop for an optical system.