Changes

The AMX Art software uses the CPC's 300Hz interrupt to read the joystick port 0 (at least it tries to do that, while moving the mouse pointer, the software accidently disables IRQs, and so, misses some interrupts). This is giving it a relative low resolution of max 300 mickeys per second (or actually less, due to the missed IRQs).

The AMX Interface hardware basically converts the incoming mouse signals to joystick 0 signals, issuing LOW pulses (per mickey) on the corresponding direction lines. The protocol is thus very simple (unlike modern RS232 and PS/2 mice, the hardware interface doesn't contain any motion countersreport anything for joystick 1 when connected to the CPC's joystick port (which provides both joystick 0 and joystick 1 input).

In addition the AMX mouse doesn't appear to clash with the keyboard.  The protocol is thus very simple (unlike modern RS232 and PS/2 mice, the hardware doesn't contain any motion counters).  Row9.Bit0 Joy1up LOW for 1/300s per mickey, when mouse moved up Row9.Bit1 Joy1down LOW for 1/300s per mickey, when mouse moved down Row9.Bit2 Joy1left LOW for 1/300s per mickey, when mouse moved left Row9.Bit3 Joy1right LOW for 1/300s per mickey, when mouse moved right

Note II: Looking at the photos, it seems that /joystick1 (keyb row 9 select) is wired to the multivibrator, so the mickey timings may be software controlled; accordingly, software would be required to deselect keyb keyboard row 9 between each read.  Confirmed: Software will select keyboard row 9 to read the mouse, but then MUST deselect it to read the mouse correctly. For example, the loop here doesn't work:  ld bc,&f40e ;; PSG register 14 (keyboard) out (c),c ld bc,&f6c0 out (c),c ld bc,&f600 out (c),c ld bc,&f792 ;; PPI port A input out (c),c ld bc,&f649 ;; select keyboard row 9 (joystick 0) out (c),c update_loop: ld b,&f4 in a,(c) jp update_loop whereas the following does work:  ld bc,&f40e ;; PSG register 14 (keyboard) out (c),c ld bc,&f6c0 out (c),c ld bc,&f600 out (c),c ld bc,&f792 ;; PPI port A input out (c),c update_loop: ld bc,&f649 ;; select keyboard row 9 (joystick 0) out (c),c ld b,&f4 in a,(c) ld bc,&f640 ;; deselect keyboard row 9 (by selecting keyboard row 0) out (c),c jp update_loop Selecting the joystick for longer doesn't appear to change the value. The value is updated when the joystick is deselected.

Moreover, the == Compatible mice/Interfaces == The [[Dk'tronics Mouse Interface]] seems to be AMX compatible, too. (Not confirmed if it is really compatible, but with the circuit looks very similarAMX in that it uses joystick directions for the mouse and joystick fire for the buttons.) (though dkThe mice are not interchangeable; the Dk'tronics seems to support mouse interface uses a mouse with a standard joystick connector. As confirmed by user Spookspring on 29.9.14, only one a single mouse button, not three buttonsis supported by the Dk'tronics interface.)

[[Category:HardwareInput Device]] [[Category:Peripherals]] [[Category:Manual]][[Category:Amstrad Products]]