RE: [avr-chat] AVR EEPROM cell: Does 0xff mean it it is erased?

[Weddington, Eric]

> -----Original Message-----
> From: address@hidden 
> [mailto:address@hidden
>  On Behalf Of Bob Paddock
> Sent: Sunday, October 18, 2009 7:16 AM
> To: address@hidden
> Subject: Re: [avr-chat] AVR EEPROM cell: Does 0xff mean it it 
> is erased?
> 
> > IIRC only Freescale HC12 flash erases to 0. At least thats 
> the only I have
> > encountered.
> 
> Some serial EEPROMs, at least old Xicor ones, erased to 0xFF but as
> shipped from the factory they contained a "checker board" 
> pattern.  Looked more
> like junk when doing a read, because the rows and columns were
> physically different
> than what you would logically expect.

Wow. That's a bit strange.
 
> I asked the Xicro factory about that, and they set it was to 
> expedite their
> test times.  Ever since I've never made the assumption a new 
> factory part
> comes in the erased state, unless that is explicitly mentioned in the
> data sheet,
> of any programmable part.

Very good point.