PAL-1, KIM-1, and Memory

[Will Senn]

I read in the KIM-1 Manual that it came with 1K but was capable of addressing 64K addresses - $0000-$FFFF. In the PAL-1 world, it comes with 5K, and there is a 32K RAM expansion and a 32K ROM expansion...

In the PAL-1 Memory Map, it shows the 5K, some optional stuff, the mapped timers, RAM, and ROMs for the 6532, then $2000-$FFFF are shown as available for expansion.

Some questions:

Is the bottom 8K always dedicated to the first 5K RAM + optional, I/O, Timers, RAM of 6532, and mapped ROMs?

Does the 32K expansion really mean 37K RAM + 3K mapped stuff?

Why a 32K expansion and not 64K?

Lastly, from the ROM doc:

In the PAL-1's memory map, there was previously a 16K portion of unused memory between $A000 and $DFFF. This lies between the upper most part of the 32K RAM expansion ($2000-$9FFF) and the 'mirrored' portion of the bottom 8K ($0000-$1FFF mirrored at $E000-$FFFF).

What is this talking about? Where can I find the memory map showing the 16K unused memory and this mirrored stuff? Is this documented somewhere?

Trying to make sense of the many memory locations and their use/availability.

Thanks!

Will

[Hans Van Slooten]

Scroll down this page for using a 32K mod to add an additional 16K:
http://retro.hansotten.nl/6502-sbc/kim-1-manuals-and-software/kim-replicas-and-clones/pal-1/

Fun fact, the 6510 processor (an upgraded 6502 used in the C64) added
6 pins P0-P5 which was used to control the memory map so you could
take advantage of the 64K by moving things around and allowing things
like the VIC-II video chip to look at different memory than the
processor was looking at at the same address.

Hans V

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