Keyboard Scan; Fig. 2.17 Electrode Wiring - Brother DP-525CJ Service Manual

SERVICE MANUAL
8.2.

Keyboard Scan

Fig. 2.17 shows the pattern from wiring electrodes on the board (this figure shows only
simplified wiring for ease of explanation and is slightly different from the actual wiring).
Refer to Fig. 2.17 to understand the keyboard scanning operation described. When a
key is not pressed, continuity does not exist in any combination of the matrix (e.g. X1
and Y1 or X2 and Y2). For example, if key [A] is pressed, continuity will exist only in X2
and Y3, but not between any other pairs of points which are left in the OFF status. In
other words, if continuity exists between X2 and Y3, it means that key [A] is being
pressed.
Pattern Circuit

Fig. 2.17 Electrode Wiring

2-17
THEORY
Electrical
Pattern Circuit