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Re: Read Speed



I wonder of anyone on the list has faced the same problem which
I did. Using a B69000 graphics chip (from Chips & Tech., later Intel,
can't remember what they ware now), I had no problem burst writing
into its frame-buffer SDRAM (it is on-chip), nearly full speed @ 33 MHz.
However, when it came to read, although bursts worked OK, they were
mostly filled with wait states...

Technically, I see no reason why an SDRAM should be burst writeable
several times faster than readable. Either they had some error in
their state-machines inside (hopefully removed with the newer B69030),
or did they deliberatly (imposed from above?) slow it down so one
cannot use the chip for real-time video capture to system memory.

Dimiter

----------------------------------------------------------------------
Dimiter Popoff
Transgalactic Instruments, Gourko Str. 25 b, 1000 Sofia, Bulgaria
http://transgalactic.freeyellow.com
Email: tgi@bulnet.bg, tgi_earth@yahoo.com
Phone: 00359/2/9923340, 00359/2/9805997, Fax: 00359/2/9540384