AVR-Chat

On 18 Sep 2008 at 15:07, David VanHorn wrote:

> On Thu, Sep 18, 2008 at 1:36 PM, David Kelly <dkelly@hiwaay.net>
> wrote:
> > Anyone have an idea as to how fast an AVR can read an SD card or
> CF
> > card? Am in need of sustaining 10E6 bits/sec. At first glance this
> gives
> > me 16 clock cycles per byte at 20 MHz. This could work if the
> timing on
> > the memory card is deterministic without periodic pauses, that I
> don't
> > have to buffer in AVR memory, and have interrupts disabled.
> 
> 
> Well... Define "read"..  :)
> 
> In that video project, I had to stream 30 fps to a color LCD
> display.
> I only actually looked at 16 words of the data from the nandflash,
> for
> the rest of it, I set up the hardware so that the low edge of the
> read
> pin was a read pulse to the nandflash and the high edge of the
> same
> pulse was the write to the display.  So, to do a frame, all I had
> to
> do was cbi and sbi 20,000 times.  While that's tedious to write in
> straightline code, it's blisteringly fast.
> 
> ------------------------------------


	"out PORT, reg" would be two times faster...

	Mark Jordan