ZEUS - NEW ZX SPECTRUM 128k CLONE SPECCYFICATION:
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Codename: 	ZEUS
CPU:		Z80A
ROM:		32kB (standart ZXS128k ROM), expandable up to 64kB
RAM:		128kB, expandable up to ???kB
Sound:		AY-3-8912(10) or YM2149
Keyboard:	standart AT or PS/2
Mouse:		standart PS/2 through convertor to Amiga mouse.
Joystick:	Kempston

Other I/O:	Analog RGB or SCART, Standart TAPE I/O 5pin DIN,
		ABC/ACB Stereo, ZEUS BUS/EXPANSION SLOT

Some descriptions:
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MEMORY

Base 32k ROM & 128k RAM is paged on port #7ffd like original
ZX 128k Spectrum. Additional ROM is paged on port #1ffd, bit 0 & 1
like original ZXS +2a/+3. Also ALLRAM mode can be used.

If additional RAM is present then it is paged on port #1ffd, bits
5-7 (something like Scorpion). There should be switch(es) on board 
which allows paging like Pentagon (port #7ffd, bits 6 & 7, port ???,
bits ???). This is only for compatibility with russian clones and
software that comes from east.

CPU

Processor runs at 3.528 Mhz. Scanline timings probably are different
due to integration. Real values are not known yet but I guess there
are 64 scanlines before TV picture, 312 scanlines per frame, 226-T
states per scanline. The real T-states per frame are also not known
yet, but I guess there are 70512 T-states per frame.

ULA

It is implemented to PLD and all known bugs are corrected (like
snowing when reg. I is set to contended memory). Port #fe should be
same as on original ZXS 128k. Adresses are fully decoded so ZEUS
will react only to correct port.

SOUND

Classic AY-3-8912 is used. It can be substituted with YM2149 which
is fully compatible with AY. Standart ports are used:
#fffd - registers
#bffd - data
Audio output is ABC/ACB switchable. Beep is mixed to center channel
of audio output and it can be switched on or off.

ZEUS BUS/EXPANSION SLOT

This is internal bus which can be used for direct expansion
interfaces, like IDE or FDD controller. There is also a
ZEUS BUS>ZXS BUS convertor available, which allows to connect
existing peripherals like +D, Betadisk or MB-02+.

EXPANSION INTERFACES

These are internal cards plugged to ZEUS BUS. They expands ZEUS's
abilities and it is possible to plug in more cards because they
are through.

PSU

ZEUS requires any power supply which can provide 12V DC at 3A.



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