Re: [Qemu-devel] SPI EEPROM device model

[Krzeminski, Marcin (Nokia - PL/Wroclaw)]

> -----Original Message-----
> From: EXT Peter Crosthwaite [mailto:address@hidden
> Sent: Monday, November 30, 2015 7:45 PM
> To: Krzeminski, Marcin (Nokia - PL/Wroclaw)
> Cc: address@hidden
> Subject: Re: SPI EEPROM device model
> 
> On Mon, Nov 30, 2015 at 12:53 AM, Krzeminski, Marcin (Nokia -
> PL/Wroclaw) <address@hidden> wrote:
> > Hello,
> >
> > I need to write some SPI eeprom device model (probably AT25128B or
> AT93C56).
> > I can not see any such device in qemu, but this time I want to ask
> > before I start to implement, if something that can speed up work is already
> present somewhere ?
> > Maybe do you have some preferences which eeprom device is better to
> have in qemu?
> >
> 
> So some of those EEPROM devices are nearly identical to M25P80 in
> functionality, the main difference being that individual cells can be
> programmed from 0 back to 1. A quick look at a AT25128B datasheet looks
> like this may be the case. Read and write instructions as the same encoding
> as M25P80.
> 
> Search m25p80 for WR_1, which is a flag you can set that allows write of 1 to
> individual bits. I think can become a feature of M25P80 (more table entries) 
> if
> the basic instructions are just an M25P80 subset.
> 
The goal of my question was to be sure that there is no such device model 
implemented somewhere.
I target to extend M25P80 with some eeprom device, will see if this make sense.

Thanks,
Marcin

> HTH
> 
> Regards,
> Peter
> 
> > Regards,
> > Marcin