(Click on image for a close-up)
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Here are the technical specs of the prototype SFC, circa
mid-1989...
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Performance:
PROTOTYPE SPECS, REMEMBER!
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1.
CPU (16-bit CPU)
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memory
space
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14 Mbyte
maximum addressable
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system clock
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1.79Mhz,
2.68Mhz, 3.58Mhz automatically switchable
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work RAM
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256Kbit
(32Kbyte) standard
PROTOTYPE
SPECS!
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2.
PPU (Super Famicom TV interface LSI)
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BG layer
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modes:
8 modes
layers: maximum 4 layers
resolution: noninterlace: 256(512)x448
interlace: 512x448
colour capability: max 256 colours (8bit/dot)
character size: 8x8, 16x16
palette: 2,048 colours out of 32,768 colour maximum. (depending
on BG mode)
additional functions: rotation, enlarging, shrinking, column
and line partial scrolling
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animation
layer
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sprites:
max. 128 on-screen, 280 pixels (35 8x8 sprites) per scanline
character size: 8x8, 16x16, 32x32, 64x64 in 4 arrangements,
individually selectable
palette: 128 colours out of 32,768 colour maximum, 16 colours
per character
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additional
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V-RAM: 64Kbyte
standard
special effects: window, mosaic, screen addition/subtraction
(transparency), fixed colour addition/subtraction, brightness
adjustment
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3.
APU (Super Famicom Sampler Stereo Audio Chip)
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audio source
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waveform
operation (ADSR?), PCM, noise, etc. in 8 individual channels
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additional
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effects
(digital echo) available
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•I/O
(input-output):
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cassette
connector
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62-pin (CPU
address bus, data bus, PPU address bus, etc.)
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expansion
connector
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20-pin (programmable
I/O, external latch, sound input, etc.)
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controller
1,2
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5-pin
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A/V output
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12-pin (R,G,B,
video, Y,C, sync, sound L/R, etc.)
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AC adaptor
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same type
as Famicom
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RF output
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TV channel
1 or 2
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•System
Dimensions: W 200mm x D 242mm x H 72mm
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•Weight:
1160 grams
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•Opti
onal
Parts:
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AC adaptor
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same as
the Famicom's
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RF switch
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same as
the Famicom's
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controller
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Super Famicom-specific
(sold separately)
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stereo cable
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Super Famicom-specific
(sold separately)
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S-Video
cable
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Super Famicom-specific
(sold separately)
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RGB cable
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Super Famicom-specific
(sold separately)
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So it looks like the SFC was pretty much shippable then. The only big
differences I can see between these specs and that of the released version
is much less main RAM. The release SFC has 128Kbytes of RAM, a very large
increase. Most games don't use such a whopping amount of RAM, except for
SlowROM games to run their code in at 3.58Mhz. So, perhaps Nintendo added
the RAM in to get that speed boost.
Hmm... 2048 colours at once in the BG???!?!? (A technically-savvy friend
has pointed out that this is the SFC's "direct colour mode"
which displays 256-colour tiles, but with a lower single bit of colour
selectable from the palette memory (256x8) for each tile. In other words,
a mostly useless colour mode.)
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