Operation Unit Control - Konica Minolta 7020 Service Manual

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Operation Unit Control

2
UD3
UD1
OP TXD
OP RTS
OP RXD
OP CTS
UD2
UD0
SGND
SGND
SGND
5VDC
5VDC
CB
The operation unit consists of the OB (operation board),
LCD (display board), PAKB (panel key board), INV2
(display inverter), and PSWB (power switch board). The
LCD includes a backlight (driven by INV2) as well as touch
switches that are linked to the display content.
The operation unit is driven by the OB based on serial data
output by the CB (overall control board).
1. Operation
a. LED ON/OFF control
The LEDs installed on the OB are driven ON/OFF by
the OB's internal CPU in accordance with serial data
received from the CB.
b. LCD display control
(1) LCD display operation
The LCD generates various displays in accordance
with 4 bit parallel data transmitted from the CB
through the OB.
(2) Backlight ON operation
The backlight (cold cathode tube) is included to make
the display easier to read. The backlight is driven by
the INV2, which is controlled by the OB.
X2
Y2
PAKB
X1
Y1
SCAN0
SCAN1
SCAN2
SCAN3
SCAN4
FAXOB
SCAN5
(OPTION)
SCAN6
SCAN7
RTN3
RTN4
RTN5
LCD
5VDC
INV ON (PWM) INV2
SGND
SW2
SUB SW
SGND
OB PSWB
(3) Touch switch control
The LCD includes touch switches that allow the user
to make selection by pressing directly on the screen.
These switches are controlled by the OB.
c. PSWB (power switch board) control
Switching ON of SW2 on the PSWB (power switch
board) while SW1 (main power switch) is ON causes
power to be supplied to all loads. Note that this
switching operates only if SW1 is already ON.
2. Signals
a. Input signals
(1) OP RXD (OB −> CB)
Serial data informing CB of the OB operating status.
(2) OP CTS (OB −> CB)
Indicates that data transmission from the OB to CB is
in progress.
While this signal is [H], the CB will not transmit OP
TXD.
b. Output signals
(1) OP TXD (CB −> OB)
Serial data informing OB of the machine operating
status.
(2) OP RTS (CB −> OB)
Indicates that data transmission from the CB to OB is
in progress.
While this signal is [H], the OB will not transmit OP
RXD.
2-M-4