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Re: Are different memory banks special?
- Subject: Re: Are different memory banks special?
- From: "David Wilson" <mcs6502@gmail.com>
- Date: 25 Feb 2007 17:18:36 -0800
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On Feb 26, 12:06 pm, Tristan Mumford <xtristan.xmumf...@xgmail.xcom>
wrote:
> What I want to know is whether there is anything special about the 3
> different banks of RAM in an apple ][?
Yes (if you use standard memory select blocks or have a later board
that omits the 4K/16K option). Row C is memory locations 0000-3FFF
with 16K chips which covers pages 00 (zero page), 01 (stack), 04-07
(Text Page 1). If these chips do not all work the system is useless.
> One other question. I'm asking because I'm doubting myself. Looking at an
> apple][ board, 6502 and slots up back, CHARGEN etc up front, which is the
> lsb column of RAM. The left or the right?
Left.
According to the circuit diagram in the Red Book, C3/D3/E3 are data
bit 0 and C10/D10/E10 are data bit 7 with the data bits running 0 1 2
3 4 5 6 7 across the board from left to right.