Copystar CS-2030 - Fax Operation Unit PCB

3B1
2-2-9
2-2-3 Fax operation unit PCB
Keyboard matrix circuit
LED display matrix circuit
MPCB
SCAN4-7
LEDON0-4
KEY SENS0-7
FOPCB
Figure 2-2-5 Fax operation unit PCB block diagram
The fax operation unit PCB (FOPCB) consists of an LED display matrix circuit and a keyboard matrix circuit. The scan
signals SCAN4 to SCAN7 are output to both matrix circuits from the main PCB (MPCB).
LED lighting signals LEDON0 to LEDON4 are also sent from the main PCB (MPCB) to the LED display matrix circuit. The
LEDs light when they are on the intersection of the lines of the scan signals SCAN4 to SCAN7 and LED lighting signals
LEDON0 to LEDON4.
When a key on the keyboard is pressed, it is identified by tracking the intersection of the lines of the scan signal (SCAN4 to
SCAN7) and the return signal (KEY SENS0 to KEY SENS7) to the main PCB (MPCB).