Chapter 1 -Introduction to RAMBO XL
CHAPTER 1-INTRODUCTION TO RAMBO XL
RAMBO XL Compatibility
RAMBO XL will work in any Atari 800XL or 1200XL computer
regardless of which ANTIC chip is used. The 1200XL will require
four jumper wires to be soldered along with soldering of the ribbon
cable. The 800XL will require one or two jumper wires to be
soldered along with soldering of the ribbon cable. Additionally,
some 800XL computers have integrated circuits (ICs) soldered
directly to the printed circuit board (PCB). If that is the case, we
strongly recommend you send your computer to ICD for
professional installation.
Compatibility With the 130XE
RAMBO XL makes your 800XL or 1200XL compatible with the
130XE in the CPU mode for extended memory. This means that it
will work with programs like BASIC XE from OSS and also support
the Ramdisk version of Atari DOS 2.5. Although RAMBO XL
actually gives you 256K of memory, the 6502 micro-processor can
only address 64K at one time. To add memory and get around this
limitation, bank selecting is used. This method used by both the
130XE and RAMBO XL uses a 16K window from $4000 to $7FFF in
the computer's memory map. These banks are controlled by the
unused ports of the 6520 PIA. The 130XE switches its four 16K
blocks of memory, one set at a time, through this window. RAMBO
XL switches twelve 16K blocks with the last four being addressed
the same as the 130XE. (See technical notes for programming
information).
RAMBO XL is compatible with the 130XE in the CPU mode, not the
ANTIC mode. The ANTIC mode allows the display to remain
undisturbed even if the display memory falls into the $4000-$7FFF
range and the banks are changed. If this happens with RAMBO XL
installed, the display will flicker as banks are changed. The program
will still operate properly except for the annoying
flickering of the screen. This display flickering can be prevented by
keeping your display list out of $4000-$7FFF.
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