Basic HTML Version
SWITCH MATRIX
White
~
0"'"0-
Green
6
Green·
Blue
J206-6
U20-13
FLIPPER
GROUNDED
SWITCHES
DEDICATED
GROUNDED
SWITCHES
LEFT
LIGHT
SLINGSHOT STANDUP
TARGET
RING·
MASTER
UP
62
NOT
USED
72
RAMP
ENTER
73
75
VOLT
NOT
LEFT
USED
16
76
RIGHT
NOT
NOT
t
IN-LANE
USED
USED
68
78
SWITCH MATRIX CIRCUIT
r------------------------------,
: Column (example)+12V
I
OFF
I
ON
I
I
I
:
G reen- XXX,P -- l-- ,
I
CPU BOARD PLAYFIELD
74HC237
+5V
I
I
I
:
1470pf
:
: Row (example)
~
:
L
~
ROW
OFF
ON
SWITCH OPEN H
SWITCH CLOSED L
The microprocessor is constantly strobing the column side of the switch. When point "An on the column
circuit toggles low, the column side is active. 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.
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