Re: [Gumstix-users] Gumstix ADC data rate and overhead?

[Søren S. C. <li...@ss...>]

> I may pick you brain later for the nitty details on said DMA code. We'd
like to use the Overo 
> for a near-real-time data-feedback device, and so the DSP should then be
free to do some 256N 
> FFTs in its spare time as part of it. Adding an ADC is no problem; we
might even be able to 
> use 8 bits if we AGC appropriately - bandwidth and FFT performance usually
go way up.

> Any idea as to the max DMA rate for the Overo? 

Hi Ray,

You are welcome. Sorry for first getting back to you now, but I’m currently
pretty much in a hurry :-)

With Respect to OMAP max DMA rate, I really think it's normally only limited
by the IP blocks requesting the DMA operation and the overall data ports
(SDRC/GPMC) in/out rate. In case you choose to use the ISP for capturing
data from the AD9990 chip, I think you should easily be able to go with the
maximum rate of 65MSPS (with 8 bit data width this is only ~5-6% + overhead
of the overall DDR memory bandwidth). The ISP goes to around 130MSPS (in 8
bit mode).

More info can be found at: http://focus.ti.com/lit/ug/sprufa2b/sprufa2b.pdf

Best regards - Good luck
  Søren