DSPRelated.com
Forums

C6711 with SDRAM and CL=2

Started by Stephen Turner December 20, 2001
Hi

In an attempt to squeeze a little more performance out of our C6711 design,
I'd
like to try running the SDRAM (Samsung 2Mx32) with a CAS Latency (CL) of 2
instead of 3.

The Samsung SDRAM I'm using will support a CL of 2 when running at 100MHz,
which is the speed we are running the EMIF at.

I've tried this, with no success and was wondering if anybody has achieved
this or could offer any more insight on why it may not be working.

Stephen Turner
AudioScience, Inc.



Stephen-

Just a guess here, but I bet there's good reason the processor speed on the DSK
C6x11 boards is 150 MHz, not 160, 166, 200 (C6211) or whatever the chips are
rated at. It's likely that the 150 MHz value, combined with the slowest memory
timing register values allowed by the C6xxx devices, just fits within the -7 and

-8 (nsec) access time SDRAMs used on the DSK boards, and keeps the cost of the
board down by not requiring faster SDRAM devices.

What is the access time on your SDRAMs?

Jeff Brower
DSP sw/hw engineer
Signalogic

On Thu, 20 Dec 2001, "Stephen Turner" <> wrote:
>Hi
>
>In an attempt to squeeze a little more performance out of our C6711 design,
>I'd
>like to try running the SDRAM (Samsung 2Mx32) with a CAS Latency (CL) of 2
>instead of 3.
>
>The Samsung SDRAM I'm using will support a CL of 2 when running at 100MHz,
>which is the speed we are running the EMIF at.
>
>I've tried this, with no success and was wondering if anybody has achieved
>this or could offer any more insight on why it may not be working.
>
>Stephen Turner
>AudioScience, Inc.