Peripheral 1 Register
From SpecNext official Wiki
Number | $05 |
---|---|
Readable | Yes |
Writable | Yes |
Short Description | Sets joystick mode, video frequency and Scandoubler. |
Bit | Function |
---|---|
7-6 | Joystick 1 mode (LSB) |
5-4 | Joystick 2 mode (LSB) |
3 | Joystick 1 mode (MSB) |
2 | 50/60 Hz mode (0 = 50Hz, 1 = 60Hz) (0 after a PoR or Hard-reset) |
1 | Joystick 2 mode (MSB) |
0 | Enable Scandoubler (1 = enabled) (1 after a PoR or Hard-reset) |
Joystick modes are as follows:
Code | Effect |
---|---|
%000 | Sinclair Joystick 2 (maps to keys 6,7,8,9,0) |
%001 | Kempston Joystick 1 (uses port Kempston Joystick ($xx1F / 31)) |
%010 | Cursor Joystick (maps to keys 5,6,7,8,0) |
%011 | Sinclair Joystick 1 (maps to keys 1,2,3,4,5) |
%100 | Kempston Joystick 2 (uses port Kempston Joystick 2, Joystick I/O ($xx37 / 55)) |
%101 | MD 1 (3 or 6 button joystick port Kempston Joystick ($xx1F / 31)) |
%110 | MD 2 (3 or 6 button joystick port Kempston Joystick 2, Joystick I/O ($xx37 / 55)) |
Older version of this page warned about configuring at most one joystick as Kempston-1 and at most one as Cursor. The specnext.com refreshed documentation about ports does not warn about such limitation, but rather proceed with caution and avoid setting up both joysticks to the same type (unless somebody from core team clarifies this).
"MD" above refers to controllers compatible with SEGA Mega Drive system. The 6 (and 3) button variant is mapped onto Kempston port this way (mirroring XYZ buttons on the ABC buttons, so only 4 distinct buttons are supported):
Bit | Joystick action |
---|---|
7 | "start" button |
6 | A or X button |
5 | C or Z button |
4 | B or Y button |
3 | Up |
2 | Down |
1 | Left |
0 | Right |