Re: [stella] Nick's PlayField Graphics Demo: Question

Subject: Re: [stella] Nick's PlayField Graphics Demo: Question
From: "Roger Williams" <mer02@xxxxxxxxxxxxx>
Date: Thu, 11 Jul 2002 21:09:23 -0700
From: Roagie <roagie@xxxxxxx>
> Is there a memory map of the 2600?

RAM is 128 bytes from $80 through $FF, and is mirrored
from $180 through $1FF which is convenient since the
stack lives in the $1XX page, and this way the stack
can share RAM which otherwise is entirely in page 0.

TIA registers are mapped from $0 through $3F.  You
get different ones depending on whether you read or

PIA registers are mapped $280-$2FF.

All this low-page stuff is repeated throughout the
lower 4K of memory $0000-$0FFF.

ROM is 4K from $1000 through $1FFF.  You can
call this $F000 through $FFFF if you prefer; it's all
the same.  The 6807 only has 13 external address lines
so it is limited to 8K overall memory map; the 6802
instruction set sees this repeated to fill the 64K address
space of the CPU instruction memory map.

You need the "Stella Programmer's Guide," available
on most fine Stella resource sites, to explain what the
registers are (if a bit cryptically).

--Roger Williams

Archives (includes files) at
Unsub & more at

Current Thread