Hi,
I have added a ZX80 emulation mode to my NXP81 project and found some 'flicker free' games like Pacman and Krazy Kong which seem to work quite nice. On the opening screen you can select two kind of joystick modes: Sinclair and Kempston but so far I have been unable to find the hardware specifications for these. Are these IO port bound or do these interfaces emulate keys ?
ZX80 joystick port
ZX80 joystick port
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Re: ZX80 joystick port
Kempston is a joystick interface that is a Spectrum "standard", but often they came with a ZX80/ZX81 sized edge connector.
The ones with such a connector can be used on ZX80's and ZX81's as well as Spectrum's.
They are read via IN A,31 in machine code (port 31 dec) but often have very basic port decoding.
Not fully sure what Paul means about "Sinclair" joysticks, but probably means keys 1,2,3,4,5 or 6,7,8,9 and zero. This is an official standard on Speccies (like Interface 2, Amstrad +2, +2A, +2B and +3). Sinclair joystick ports map joysticks to one of these two groups of keys.
Mark
The ones with such a connector can be used on ZX80's and ZX81's as well as Spectrum's.
They are read via IN A,31 in machine code (port 31 dec) but often have very basic port decoding.
Not fully sure what Paul means about "Sinclair" joysticks, but probably means keys 1,2,3,4,5 or 6,7,8,9 and zero. This is an official standard on Speccies (like Interface 2, Amstrad +2, +2A, +2B and +3). Sinclair joystick ports map joysticks to one of these two groups of keys.
Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
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Looking forward to summer later in the year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
Re: ZX80 joystick port
I had setup a debug function on any unknown IO ports but when I selected Kempston it did not trigger once..They are read via IN A,31 in machine code (port 31 dec) but often have very basic port decoding.
Have to dig deeper I guess or just add some code to emulate the cursor keys with the joystick.
Re: ZX80 joystick port
I would guess the joystick implementation comes from the fact that Paul sells a ZX81 emulator on a Spectrum ROM cartridge - so I guess the support is for the Kempston interfaces (for the Spectrum, or for the ZX81 if you can find one the right width), or for the Sinclair joystick ports built into the ZX Interface 2 on the Spectrum.
Rich Mellor
RWAP Software
RWAP Adventures
SellMyRetro
Retro-Printer Module
Also Involved in:
Icephorm
RWAP Software
RWAP Adventures
SellMyRetro
Retro-Printer Module
Also Involved in:
Icephorm