Additional cartridge ROM question

Additional cartridge ROM question

From: Jim Brain <>
Date: Tue, 24 Mar 2009 00:55:46 -0500
Message-ID: <>
I have an option to make the cart a 16kB cart.  As I understand the 
various web sites, my PRG, and C=Hacking, I ground EXROM and GAME and 
then my 16kB will appear at 8000-9ffff (ROML) and a000-bfff (ROMH)

So far, so good.

But, if EXROM and GAME are LOW, but HIRAM and LORAM are low as well, do 
I get RAM at the two 8K locations, or does EXROM and GAME override any 
LORAM/HIRAM settings?

Why do I ask?

Well, if HIRAM/LORAM take precedence, I am more comfortable setting up a 
16kB image, knowing that if a user has an 8KB image they want to use, 
they can simply et HIRAM to 0 and get 8KB of RAM.  If I'm cutting them 
off from 8kB of RAM permanently by bringing both EXROM and GAME low, 
then I'm not sure I want to support 16kB images.

The PRG and the various web sites were not helpful in resolving my question.


Jim Brain, Brain Innovations                                      (X) 
Dabbling in WWW, Embedded Systems, Old CBM computers, and Good Times! 

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Received on 2009-03-24 07:14:33

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