Date   : Tue, 16 Jun 2009 11:38:34 +0100
From   : michael.firth@... (michael.firth@...)
Subject: Econet Rom version differences

> -----Original Message-----
> From: 
> bbc-micro-bounces+michael.firth=bt.com@... 
> [mailto:bbc-micro-bounces+michael.firth=bt.com@...
> .uk] On Behalf Of Andy Ford
> Sent: 16 June 2009 11:21
> To: bbc-micro@...
> Subject: Re: [BBC-Micro] Econet Rom version differences
> 
> Mike Tomlinson wrote:
> > Can you tell me whether this is 8k or 16k please Andy?
> >
> >   
> 
> As far as I know, its an 8K eprom created for me from an 
> image, rather 
> than (what's correct terminology here?) a "factory produced" rom...
> 
>  From memory (as I don't have quick access to the machine) I 
> can't see 
> the number on it as it has a sticker on it so am not able to see what 
> size it is (although I suppose that does not mean that much 
> as it could 
> be a 16K chip)
> 
> I'm not that well versed on the details, but if there is a 
> quick couple 
> of commands I can type in to find out the size (if it helps 
> the machine 
> its in also has one bank of Sideways Ram in one of the Rom sockets) , 
> I'll be quite happy to try that for you to get the information. :)
> 
> 
The easiest way to see if an inserted ROM is 8K or 16K is to compare the
contents from &8000 and &A000 - if it's a 16K ROM they'll be different, if
its an 8K ROM they'll be the same. For example, using ADT's *MDUMP command:

*MDUMP 8000+50 8 5

*MDUMP A000+50 8 5

Will give you the first &50 bytes of ROM 5 at both addresses.

Another possibility is that its an 8K image in a 16K ROM, then &A000 onwards
is likely to be all 00s or FFs, depending on the programmer.

Regards

Michael