This adapter provides the connection of 2 controllers on each MSX joystick port. It works with Master System and Genesis 3 and 6 button controllers and provides the following operating modes, selected at power up:
In this mode the buttons are mapped to MSX standard joystick buttons.Second controller accessible via Basic using pdl(x) function, example:
100 IF PDL(0) = 0 THEN GOTO 1000 : REM UP Action
Basic Mode Timing:
After a short pulse issued by MSX to read the paddle the outputs assume the state of the Controller 2 and stay for 32us, then fall to zero for more 32us. Such time is enough for MSX to count up to 3 during GTPDL Bios call and to detect the end of the temporization as well.
CALL JOYLIB.GTJOYMEG6 ; do some stuff with controller 1 data CALL BASELIB.FLIPPORTOUT CALL BASELIB.FLIPPORTOUT CALL JOYLIB.GTJOYMEG6 ; do some stuff with controller 2 data
The circuit times out after 3ms which gives plenty of time in between reads to process data from first controller.
JoyMega mode Timing