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Re: II specs? Help!
John Lundgren (jlundgre@news.kn.PacBell.COM) wrote:
:
: Andy Stout (andy@stout.demon.co.uk) wrote:
: : If anyone can help provide some technical info on the original Apple II (ie
: : processor, clock speed etc) I would be absurdley grateful. Nowehere else
: : I�ve tried (including the rather useless Apple Technical Library) has been
: : able to come up with anything.
: : Cheers,
:
: : Andy
:
: The Apple ][ had a 1MHz 6502 processor in it. I've forgotten almost all
: the other specs.
:
:
I learnt from an old book that the Apple ][ had a 1MHz 6502 CPU running at
1.024MHz clock. It had 8 expansion slot (0-7) where slot 0 can only be
used as memory expansion and slot 7 had a special video signal (some
clones don't) making it the only slot to be used with video signal
converter (eg. NTSC -> PAL).
Um... the 6502 can address up to 64K byte. $F800-$FFFF is denoted as
monitor ROM, $D000-$F7FF as Applesoft (if it is a ][+), $C000-$CFFF as I/O
addresses. The video modes are mapped as (none of them is linearly mapped):
TEXT page 1 : $0400-$07FF
TEXT page 2 : $0800-$0AFF
GR page 1 : $0400-$07FF
GR page 2 : $0800-$0AFF
HGR page 1 : $2000-$3FFF
HGR page 2 : $4000-$5FFF
mixed mode : HGR page 1 & TEXT page 1
Oh, each slot is allocated with 2K ROM addresses, $Cx00-CxFF for slot x.
Besides, in the area $04FF-$07FF & $2000-$3FFF some addresses are
assigned to the slots (what a mess!)
Additional memory is to be bank-switched in the area $D000-$FFFF (12K)
and a further 4K at $D000 is bank-switched to give a total 16K memory unit.
There is just too much to say about an Apple, serval books are needed to
explain just anything about it. It would be better if you specify on
which patricular area you are interested in.
Hope this help.
-------------------------------------------------------------------------------
William
)x.x( [O.O] )O.O( email : h9104374@hkuxa.hku.hk
O O -*- h9104374@hkusub.hku.hk