[OpenBIOS] PC-CMOS memory..

[Steve and Sue]

----- Original Message -----
From: Stefan Reinauer <stepan at suse.de>
To: <openbios at elvis.informatik.uni-freiburg.de>
Sent: 10 February 2000 15:32
Subject: RE: [OpenBIOS] PC-CMOS memory..


> Is there a secure way to access anything in the CMOS over 128 bytes? I
wrote
> some patches for the Linux nvram driver a long time ago to access not only
,64
> bytes, but 128 bytes.
> I read somewhere that everything over 128 bytes has to be accessed over
> io registers 0x72 and 0x73 instead of 0x70 and 0x71. Has anyone
information on
> that issue?

I'm not sure what you mean by 'secure', do you mean consistent?

0x72 and 0x73 do seem to be the method for accessing the upper 128-bytes of
CMOS but I'm not aware of any 'standard'. These days the CMOS is often on
the South Bridge of the chipset so you need to check the individual data
sheets, (its a while since I programmed a discrete NVRAM), some of the
chipsets have locks and other enables so it is wise to check the data.

Steve

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