From: Chris Elliott <Chris@PinsonConsulting.com> - 2007-12-12 19:04:35
> I don’t see how you’ll get those data rates on a 400Mhz system.
> You’re talking 8 clock cycles per byte for 50MB/sec. Just reading a
> byte into memory is going to take that much I would think.
> Likely why Gumstix didn’t bother to do USB 2.0.
> And there’s no PCI bus.
> So even if you do interface and IDE drive I don’t see how you’ll ever
> get those data rates.
> I don’t recall any 400Mhz CPUs ever getting those data rates on a hard
> Perhaps somebody else can comment or correct me?
The compact flash interface is IDE. Even with a fast CF card, I can't
get over around 2 MB/sec. I suspect that the driver only supports PIO
modes. Assuming the recorded data will not fit into RAM, I found the
fastest way to store off data was to send it out over Ethernet. The only
way I can think of to get near 50MB/sec is to put an FPGA on the XScale
32-bit bus and use DMA. In general, I don't think the Gumstix is the
ideal platform for a job that includes recording data at 50MB/sec.