Loading Acorn (BBC) sideways RAM.

Tony Duell ard at p850ug1.demon.co.uk
Thu Sep 16 19:04:31 CDT 2004


This is a really trivial question, but I wasn't really a BBC micro hacker 
in the old days,

I am planning some upgrdes to a BBC Model B+ (the fact that this 
particular B+ lives in the bottom of an Acorn Cambridge shouldn't 
matter...). One of them is to combine some of the ROMs (the B+ can take 
27256 32K byte EPROMs), thus freeing up some ROM sockets and put a RAM 
chip in one of them. I then have to fiddle the write-enable line [1] (should 
be easy) and I have 32K of sideways RAM.

The hardware doens't worry me (I have schematics...). But how do I load a 
ROM image into the sideways RAM? Is there some loader program I need (and 
where do I get it)? Anything I should know about the image file on disk 
(anything about the start/end/entry addreeses in the direxctory, for 
example)?


[1] I believe it's a good idea to be able to write-protect the sideways 
RAM, but I don't want to drill holes in my Cambridge. Has anoyne ever 
used the cassette motor line for this? Seems like an obvious thing to use.

-tony




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