15 Oct
2012
15 Oct
'12
3:31 p.m.
The analog input adapter (joystick interface) was
offered at the time of
release, but no joysticks (until YEARS later) - but the docs had a drawing
that was clearly and obviously the joystick of the RS Coco.
Which wouldn't ahve wored without intenral wiring changes (not just a
conencotr adapter). The CoCo jopsticks used 3-terminal pots as a
potential divider acorss the 5V supply, the slider goes ot ta voltage ADC
input on the CoCo. The IBM (and Apple ][) joysticks are variable
resistors (2 terminal) used as part of the timing network on a 555
monostable (actually a 558, which is a quad 555, wired in monostable mode
only).
You would ahve to separate the 'bottom end' of the 2 pots in the joystick
for it to work proeperly.
Of coruse it's entirely possible that IBM were planning on selling
joysticks made by the same company that made the CoCo ones, but wired fro
the 5150 adapter.
-tony