Oki B 4100 Maintenance Manual page 427

A3.4 OPE (05W) Circuit Diagram for OKIFAX 5000 Series
1. Block diagram
Figure A3.4.1 shows a block diagram of OPE (05W).
The O5WH (operation unit) circuit consists of the following blocks:
1) IC1 (one chip MOS-CPU)
• Output ports
• Input ports
2) Key switch matrix (8 rows x 8 columns)
3) LEDs (8 LEDs)
4) LCD unit
2. Key switch scanning
Output ports (KSCAN0 to KSCAN7 signal) corresponding to 8 rows of key matrix are scanned
sequentially by the software. In the case 1 is any of output from KSCAN0 to KSCAN7 signal
which corresponds to the row 8 in the block diagram, the software reads input port, KSENS0 to
KSENS7, and determines which in the row 8 is pressed.
3. LED drives and LEDs
Eight LEDs (ALARM, PHOTO, LIGHT, etc.) on the control panel are driven by output of IC1 via
resistors R1, R4-9 and R11 respectively. An LED lights on when a port output is 1.
4. In case sub-power supply is applied to the fax machine: when PC1-N, HUP-N or RIINT signal is
input to OPE unit, OPE unit controls the main power supply (120/230 board) by outputting the
MP/OFF (ACON) signal.
• PC1-N:
• HUP-N:
• RIINT:
40055101TH Rev.4
Setting LEDs on and off: 8 ports
Specifies the row during key switch matrix scanning: 8 ports
Detect the column whose key is pressed: 8 ports
Presence of document on hopper
OFF-Hook detection for TEL 1 and TEL 2 terminal
Ringing detection signal
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