Mouse in port 2 ..?

[freqmax]

Looking at the schematic of the mouse port both "joystick" port pins Vpulse, Hpulse, VQpulse, HQpulse are wired to U15 74HCT157 which is controlled by _CCK and U15 is output is wired to U4 8362 (Denise). Nothing to differentiate either port.

So is the restriction to use mouse only in port 1 a software limitation in kickstart/workbench. Or a hardware limitation ?

(schematic A500)

[freqmax]

Howcome _CCK is used to multiplex between "pulse" and "Qpulse" for the port ?, ought to be confusing to read values

(A2000 schematic)