Basic HTML Version
SWITCH MATRIX
White
---1~~~
o-Green
Dedicated
Grounded
Switches
Flipper
Grounded
Switch ••
J906·1
Lowe, Right
Flipper E.O.S.
SWITCH MATRIX CIRCUIT
i-cp-O-13oAR-6---
---- - --+12v------i
I
I
I
I
!
J207 !
PLAYFIELD
I
A
I
I
x~~--~.
+5V
I
I
1 4 7 0P f
:
: Row (example)
~
:
L
~
ROW
OFF
ON
SWITCH OPEN
SWITCH CLOSED
The microprocessor is constantly strobing the column side of the switch. When point uA" on the column circuit
toggles low, the column side is active.
When a switch closes, the row side of the circuit activates. The u+" 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 u+" input to the LM339 is above +5V, its
output is high and the row is inactive.
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