Keyboard Control Circuit; Fig. 2.18 Keyboard Control Circuit - Brother DP-525CJ Service Manual

THEORY
Electrical
8.3.

Keyboard Control Circuit

The keyboard control circuit is shown in Fig. 2.18.
The matrix pattern on the keyboard FPC controls port 7 (0:7) of CBIC (#8) according to
data signals KO0 through KO8. The LOW level signals are output to output lines KO0
through KO8. The electrode wiring is scanned line by line. The result of scanning is
input to P70 through P77 of CBIC (#8). CBIC (#8) detects which key has been pressed.
The key matrix given in Fig. 2.19 corresponds to the key arrangement shown in Fig.
2.20.

Fig. 2.18 Keyboard Control Circuit

2-18
SERVICE MANUAL