Xerox M20 - WorkCentre B/W Laser, Service Manual

Page: 261 / 314

December 2006
6-55 WorkCentre M20, 4118, FaxCentre 2218 Family
GP 17
General Procedures and Information
GP 17 PBA OPE Operation (M20F)
Purpose
To give information about the operation of the PBA OPE.
NOTE: If necessary, refer to GP 20 for the acronym list and cross reference lists of more com-
monly recognised part names.
Summary
The OPE board is separated functionally from the main board and operated by the MICOM
(HT48R50) in the board. OPE and the main use UART (universal asynchronous receiver/trans-
mitter) channel to exchange information. OPE reset can be controlled by the main. OPE
MICOM controls key-scanning and LCD and LED display. If there occurs an event in OPE
(such as key touch), it sends specific codes to the main to respond to the situation and the
main analyzes these codes and operates the system. For example, it the main is to display
messages in OPE, the main transmits data through UART line to OPE according to the desig-
nated format and OPE displays this on LCD, LED. OPE’s sensing is also transmitted to the
main through UART line and then the main drives necessary operation.
OPE PBA consists of U1(MICOM, HT48R50),LCD, key matrix, LED indicators. Refer to Refer
to Figure 1.
• Signals from the key matrix are delivered to U1 input pin group (D1-D6).
• U1 pin 48 (TX DATA) is the UART code sent to MAIN PBA.
• Display from the controller is received at U1 pin 5(RX DATA).
• LCD drive signals are sent from U1 P2-x pin group, P3-4-P3-6 pins.
• Machine status LED drive signals are sent from U1 LED0-LED7.
Figure 1 OPE block diagram