Date   : Fri, 15 Feb 2008 23:33:28 +1100
From   : msmcdoug@... (Mark McDougall)
Subject: BBC FPGA Boots to BASIC... almost...

Tom Walker wrote:

> Because there's no device there, nothing gets put on the data bus, so the
> 6502 reads what was last there, which is almost always the high byte of the
> address.

You can't really rely on that fact, it will depend on the capacitance on the 
bus and the driving characteristics of the devices. And it won't *always* be 
that value, as you pointed out.

So I'm not sure that it *needs* to be the case, although I notice MESS does 
do that... anyway it didn't get me any further, so I'm not sure it's 
important...

Regards,

-- 
|              Mark McDougall                | "Electrical Engineers do it
|  <http://members.iinet.net.au/~msmcdoug>   |   with less resistance!"