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%% The AA+ Chipset                                   by Darren Stevens %%  
%%                                     %%

Hi there!

After all those predictions and rumors in AR recently
I thought I'd put my ideas into the pot...

Being from England I will be staying with low-end Amigas for
a long time to come. At current prices an A4000/030 would cost
me more than I take home each month (a lot more for a good one!)
So while I find discussions of what the AAA will be like
interesting, I'd like to know more about the AA+ as thats what
I will be getting next..

Well thats the problem isn't it? Theres LOTS of info about the
AAA floating about, and thats not realy surprising is it? Over
here in the UK at least, the Amiga (well the A1200) is doing well,
so I think we get forgotten about while C= trys to reassure US
Amigans. So info about the AA+ is very scarse at the moment.

I'm sure it hasn't been abandoned - Dave Haynie mentioned
both the high and low end groups share staff, so whats happening?

A long dig through my old magazines has given me enough info to
come up with some informed guesses. (Most of which will probably
be wrong!)

  Firstly what is the AA+?

Lew has said that this is an improved version of the AA, with
improvements that couldn't be fitted into the AA. Basically as
I see it only the Video, sprites and palette have been improved
so far. AA+ will give a better blitter (Horay!), copper, proper
High density floppies, a FIFO buffered serial port, and 24 bit
graphics although I suspect only in normal PAL/NTSC modes.
Sound may be improved.

I expect the AA+ to have at least double the AA's bus bandwidth,
ie ~57Mb/s (thats the same as for the low-end AAA described in
AR201 Hmmmmmm....)

I would also expect an increase in chip ram, which leads to a
problem. The A1200's memory map is only 24 bits (16M) currently
this is 2 meg chip and 9 Meg Fast. Increasing chip ram to 4 or
8 Meg will not leave much space for fast ram.
 There are three solutions to this:-

 1) use a Full 020 with its full 32 bit addressing (and MMU)
 2) Get motorola to design a new EC020 with more address lines(!)
 3) use an EC030 16Mhz...

I know which I'd prefer!!!!

video modes:

   640 x 256/200 NI 24 bit 50/60 Hz  (Pal/NTSC)
   640 x 512/400 NI 16 bit 50/60 Hz  (DBLPal/DBLNTSC)
  1280 x 512/400 NI 256 Colours 50/60 Hz (DBLPal/DBLNTSC Super Hi-res)
   800 x 600 NI 256 colours 72 Hz (DBLSuper72??)
(with interlaced of course)

and possibly (depending on which info you believe!)

   1280 x 1024 NI 16 Colours 50 Hz

...Plus of course Productivity etc,

 AA+ is also going to cost less as it will only be 2 chips not 3.
I think it is possible that C= will Replace all current machines
this Autumn.
Why? - 2 reasons
- Cost: AA+ should be cheaper.
- AA was only a sort of stop-gap until AAA/AA+ were ready.

 I think I should explain what I mean by 'replace'.
Current A1200 upgraded to A1200+ with AA+ and OS3.1
CD32 also given AA+
A4000/040 Given AAA
for A4000/030 - could go either way! AAA/AA+ your guess is as
good as mine!

Cases will stay as with current models, meaning production can
carry on without having to re-tool all production lines, and
it may be possible for current users to upgrade motherboards
in their machines, saving them some cost.

One thing I hope Lew will fix is the bus rate of the AA+. From
the available evidence it seems the AA runs at the same speed
as the ECS. The graphical improvements are from fetching MORE
not more often. However the processor in the A1200 is now twice
as fast. Result:- each Custom chip set Odd cycle (remember Odd
cycle is DMA only) overlays 1 odd AND 1 even from the '020.
Hence the processor runs very slowly in chip ram. (I dont know
this for certain by the way, but it seems logical)

One other possibility, one that I think would make a *LOT* of
sense is for the functions of the two different low-end 
gate-array chips to be incorporated into one chip. I mean the
1200's super Gary and the CD32's Akiko. Result of this is a
A1200 you can plug a CD drive into, or a CD32 which turns into
a computer - both very cheaply! But this is a sensible idea and
we all know that C= don't always act sensibly do they? (Are you
reading Lew? Dave??)

 What is the upshot of these ideas of mine?

If Lew hasn't forgotten to improve the sound under AA+ the
A1200+ will be a multimedia machine to be reconned with. And
at probably the same price as the current 1200 execlent value.

The new CD32 should give both Atari and 3DO sleepless nights...
the CD32 - the least powerfull of the 3 machines is Dominating
the CD market place over here. The AA+ will put it up there with
the others spec wise, and it will still be miles ahead with
software support.

Happy computing all!


Sources (for those of you interested)

Amiga Shopper 21 - Jan '93 news (pg 11)
AUI April 1993 - Orlando Devcon (pg 22 - 26)
AUI May/June 1993 - Lew Eggebrecht interview (pg 20 - 23)
AR201, AR206 
and lots of other article/files I can't remember right now.