Re: [stella] that supercharger thingy

Subject: Re: [stella] that supercharger thingy
From: Eckhard Stolberg <Eckhard_Stolberg@xxxxxxxxxxxxxxxxxxxxx>
Date: Mon, 31 May 1999 14:12:53 +0200
At 14:42 30.05.99 -0700, you wrote:
>1. are there any documents around the net which describe how the
>supercharger
>uses and accesses the extra 2K of memory?

There is a text by Chris Salomon on Nick Bensema's Atari programming page.
( http://www.priment.com/~nickb/atariprg.htm )

>2. does anything need to be written in the extra 2K for either 4K roms
>or super-
>charger games, or is that merely used as extra ram?
>3. how does one access that extra 2K of ram...is it done the way
>bankswitching is
>done, or are there other factors involved...

The supercharger has four 2kb segments of code. Three of those segments
are RAM, one is the ROM, that has the code for loading data from the
tape. The 4kb of memory that the VCS can access for game code is
devided into two slices. The three RAM segments can be mapped in at
either slice, but the ROM can only be mapped in the 2nd slice. Which
segment is mapped in at wich slice is determined be 'writing' a
control value to the SC's contol port at $FFF8. Writing to this
port as well as writing to the SC's RAM is done in a special way,
that is different from any other bankswitching method.

>4. is there any way of saving data at all on the supercharger for later
>sessions?

The supercharger has no possibility to save somthing to the tape.


Ciao, Eckhard Stolberg



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