Mouse for ZX Spectrum
Mouse interface with two 8bit reverse counters. Readed in ports: #FADF (button bits: 0 - right, 1 - left, 2 - middle), #FBDF - X, #FFDF - Y. Usually incomplete decoding: A0, A5, A7, A8, A10, /RD, /IORQ, sometimes A9. There is port conflict with Kempston Joystick in Timex Computer 2048, that decodes only A5.
This is the recommended solution, however complicated at hardware level. In some constructions Amiga mouse can be used or PS/2 mouse with PIC converter.
Mouse connected with Z80PIO chip. Generates IM 2 vectors in moment of movement.
Special Commodore mouse works like joystick.
Amiga mouse in Kempston Joystick port
Needs special driver. The mouse status must be readed over 500 times a second to not lose movement information.
PC mouse connected with serial interface (e.g. YAMOD.8250) that generates interrupts. Works at 1200bps, what gives up 40 status informations per second.
The simplest solution is to use 8251 chip set 1200bps and MAX232 as voltage converter. (Some mice take LED power from -12V line.)
Files for download
- kempston_mouse_turbo-3c-test.pdf 638.7kB (2005-09-18 20:49)
- [cz] Description and test (source codes) of Kempston Mouse, interface made with PIC and CPLD, that supports Amiga, PC and USB mice.
- kmouse.gif 20.0kB (2005-04-11 16:19)
- Schematics of Kempston Mouse made from 4516, 74244, 74138 and 74125 chips.
- kmouse.html 15.1kB (1999-11-20 19:49)
- [en] Kempston Mouse description with ASCII schematics and assembler driver.
Links to other pages
- [cz] Description of mouse interfaces.