12 Apr
2013
12 Apr
'13
2:20 p.m.
On 12 April 2013 06:36, Raymond Wiker <rwiker at gmail.com> wrote:
There were a few other differences that appeared to the programmer/user
IIRC. I will have to dig out my Electron Advanced User Guide to check,
though (yes, that book does exist, but it is a lot harder to find than
the oen for the Beeb).
The user/programemr would not notice the memroy arrnagement, though.
Logic in the ULA does make the 64K*4 DRAM appear as a 32K*8 area of RAM
to the processor. But the hardware is a either a 64K*4 DRAM chip (41464
or similar) or a little PCB with 4 off 64K*1 chips on it.
On Thu, Apr 11, 2013 at 10:28 PM, Tony Duell
<ard at p850ug1.demon.co.uk>wrote:
Not that I am aware of... I thought that apart from external
interfaces of various forms (including sideways RAM and so on), the
principle hardware difference of the Electron from the Beeb was that I suspect you'll know this, but which 1980s
(8 bit) microcomptuer had
4-bit wide RAM at the hardware level? (The hardware did 2 memory cycles
to make up an 8 bit byte ot give to the processor).
Acorn Electron? it didn't have the Mullard teletext chip & so
couldn't do Mode 7 -
which sadly was a very popular screen mode, as it took very little
RAM, something the Model B was notoriously short of.
-tony