Basic HTML Version
White
~
a""
0-
Green
1
2
5
Dedicated
Green·
Flipper
Grounded
Grounded
Switch ••
Switch ••
J208·13
Lower Right
Flipper E.O.S.
11
41
61
71
VANISH
GENIE
NOT
NOT
TUNNEL
TARGET
USED
USED
43
INNER
LOOP
LEFT
RIGHT
JET
=
OPTO, TYPICALLY CLOSED
SWITCH MATRIX CIRCUIT
r---------------------------------,
: Col um n ( e
X
amp le ) +
12V
: -,C"-,O".,L::,;U""M,,,N:-t--'c'-t-7'---t-c-::--_
I
I
INACTIVE
OFF
:
J206:
ACTIVE
ON
:
A :
:
x
I-tl-=GC-r-ee-n---QXX
1> - ---1_ _ .
I
I
:
74HC237
I
I
OPU BOARD PLAYFIELD
White-XXX
When a switch closes, the row side of the circuit activates. The "+" input to the LM339 drops below +5V, therefore,
its output is low. Corresponding row and column switches must be low at the same time for the switch to be
considered closed by the microprocessor. When the switch opens, the "+" input to the LM339 is above +5V, its
output is high and the row is inactive.
3-2