Zon-X & the Speccy

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palmheads
Posts: 40
Joined: Thu Apr 30, 2009 8:15 am

Zon-X & the Speccy

Post by palmheads »

Hi

Think I might already know the answer to this, but thought I would ask anyway.

If you had the Zon-X AY device on an old 48k Speccy, was it compatible with games that had AY sound for the 128k speccy's?

cheers
Daryn
palmheads
Posts: 40
Joined: Thu Apr 30, 2009 8:15 am

Re: Zon-X & the Speccy

Post by palmheads »

I think this page actually answers my question!

http://zxspectrum48.i-demo.pl/aymusic.html

Answer would be no!

cheers
Daryn
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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: Zon-X & the Speccy

Post by 1024MAK »

128K ZX Spectrum Reference
Sound Chip
The AY-3-8912 sound chip is a widely used one, to be found in the MSX, Amstrad CPC range, etc. It is controlled by two I/O ports:
OUT (0xfffd) - Select a register 0-14
IN (0xfffd) - Read the value of the selected register
OUT (0xbffd) - Write to the selected register

BI-PAK ZON X
Addresses for ZX Spectrum version (the ZX81 version is incompatible with various ZX Spectrum expansions):
out 0xFF select register
out 0x7F write to register


Detailed Spectrum I/O Ports (accessed via IN/OUT opcodes)

Code: Select all

Port Binary Address   Dir Description
FFFD 11............0. W   Spectrum 128K/+2/+2A/+3 PSG index register
FFFD 11............0. R   Spectrum 128K/+2/+2A/+3 PSG data read (and RS232)
BFFD 10............0. W   Spectrum 128K/+2/+2A/+3 PSG data write (and RS232)

xxFF ........1..11111 W   Bi-Pak ZON X Soundbox PSG index
xx7F ........0..11111 W   Bi-Pak ZON X Soundbox PSG data write

xxF6 ........11110110 R/W Timex TS2068/TC2068 PSG data R/W (sound registers)
x1F6 .......111110110 R/W Timex TS2068/TC2068 PSG data R/W (and joystick 1)
x2F6 ......1.11110110 R/W Timex TS2068/TC2068 PSG data R/W (and joystick 2)
xxF5 ........11110101 W   Timex TS2068/TC2068 PSG index
All the above trawled from the internet just now.

So the answer to the question, is, no, the ZX Spectrum 128, +2, +2A, +2B and +3 use different I/O ports (addresses) to the ZON X and to the Timex computers.

I suspect most games written for the ZX Spectrum 128 will not work with the ZON X unless the programmer(s) specifically included support.

Some AY sound expansions were available that could be used on 48K ZX Spectrums with the same I/O ports as a ZX Spectrum 128 machine.

Mark
palmheads
Posts: 40
Joined: Thu Apr 30, 2009 8:15 am

Re: Zon-X & the Speccy

Post by palmheads »

Cheers Mark, that definitely answers my question - thanks for the effort!

Cheers
Daryn
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