[LinuxBIOS] rom-madness: CFI vs FWH vs SPI, 5V, 3.3, ...

Segher Boessenkool segher at kernel.crashing.org
Tue Apr 10 10:46:14 CEST 2007

> First, there's parallel flash. Parallel flash on PC mainboards has an
> address bus which is between 17 and 19 bits wide and a data bus which
> is 8 bits wide.

Bigger address busses are sometimes used; x16 flash is also
sometimes used (and shared data/address busses, too).

I agree you don't see these often on x86 PC boards though ;-)

> CFI is the Common Flash Interface as developed by Intel and friends
> and published by Intel.

Developed by AMD, Intel, Sharp and Fujitsu; published
by AMD says my version of the doc (maybe all vendors
publish their own, dunno).

> CFI covers both 8-bit wide and 16-bit wide flash.

And 32-bit wide.  Not that you'll likely ever see that on
an x86 PC :-)


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