Re: LZ: ROM pages
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Alan Bailey wrote:
>
> Could someone explain the use of rom pages and how and why they are used?
The z80 can only handle 64k of mem (Ram and ROM). Since the ti85 has
128k of rom, the rom needs to be page for the processor to use it.
On the ti85 the rom has been divided into 8 pages (page 0 to page 7).
Page 0 i s always located at 0000 to 3fff and it contains often used
system rutines. One rom page is located at 4000 to 7fff, which rom
pages is present here cen be set by writing to one of the ports.
So to call a function which is not on page 0 you first write the
page number to the port and then call the functions.
from 8000 to ffff you have the ram.
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--
_______________________________________
Dines Justesen
Email: dines@post1.com or
c958362@student.dtu.dk
WWW : http://www.gbar.dtu.dk/~c958362/
_______________________________________
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