[LinuxBIOS] Fun easy question. 512Kb or 256Kb

Bari Ari bari at onelabs.com
Tue Feb 7 15:35:26 CET 2006

Adam Talbot wrote:

> Speed in ns:
> What controls that? Can I set/change the access speed to my "bios chip"?

The timing of the Flash BIOS read and write cycles are hardwired into 
the chipset and clock synthesizer. At most there is a pinstrap (Pinstrap 
= A signal line on a chipset that is read only after RESET that is used 
to configure the chipset. The line is either tied to a High or Low via a 
resistor.) to chose the type of firmware interface, x8, x16, LPC or FWH.

For an example, see page #3 of this schematic: 

> I have a few boards that had Eon chips(120ns), I have replaced them with 
> SST's(45ns), they work fine.  Are they running faster? 

No. The chipset spec may just require a flash device of 120ns or less. 
Dropping in a faster flash device doesn't change the read access speed, 
since the speed is driven by the chipset.


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