EEPROM read/write user space program

Stefano Barbato stefano at
Fri Nov 28 21:27:35 CET 2003

I could also change in "your system will brake, very very VERY much" :)

I think that defaulting to 8bit makes sense, I agree with you. It will be more 
safer or, better, less devastating. Reading from a 16bit using 8bit will just 
confuse the eeprom that can return wrong values (usually 0xff). Writing just 
don't work or at least not on eeproms I used for testing.

So I'll change to 16bit default as soon as possible (and I'll add a -16 

I was trying to figure out if there's a non-euristic mode to detect the eeprom 
type without writing to it but, before trying, I want to buy a new 8bit 
eeprom because I don't want to play with my dimm spd (that btw is not write 

I'll let you know.

Thanks for the proofreading work :)


On Friday 28 November 2003 19:23, you wrote:
> > __________________________________WARNING____________________________
> > ___ Erroneously writing to a system EEPROM (like DIMM SPD modules) can
> > brake your system.  It will NOT boot any more so you'll not be able to
> > fix it.
> It's "break", not "brake" (also in some way I agree it does too ;)).
> And "any more" is "anymore".
> > Reading from 8bit EEPROMs (like that in your DIMM) without using the
> > -8 switch can also UNEXPECTEDLY write to them, so be sure to use the
> > -8 command param when required.
> Wouldn't it be safer to default to 8-bit and have a switch to use
> 16-bit addressing? From what you said, "reading from an 8bit eeprom
> using 16bit addressing can actually *write* to the eeprom", but what
> would reading a 16-bit eeprom using 8-bit addressing do? If it isn't
> dangerous, I believe you should default to 8-bit addressing.
> BTW, isn't it possible to detect the addressing mode?

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