List on modules for ZXMATRIX & ZXCF+ :
Kempston Joystick, 2007-04-24
Kempston Joystick (Eaglecad v4.16), 2007-10-15
Dual Joystick, 2007-10-25 (Warning! not tested)
+2upg DIY manual rev 1.1, 2008-04-28
note: The +2upg board can be used for experiments, CF select is 2 units switch, 5 more units can be added, units
can be whatever you want, a serial port ....