Kenwood TK-7180H Service Manual page 24

7. Display Circuit
7-1. TK-7180H Transceiver
The display unit consists of the Panel CPU (IC902), the
LCD driver (IC903), the TX/BUSY LED, the KEY detection, the
Backlight and the Microphone jack circuits.
The Panel CPU is a 16-bit microcomputer that contains a
64k-byte Mask ROM and a 2k-byte RAM.
The Panel CPU performs serial communication with the
Main CPU (IC404) on the TX-RX unit (B/3) and the Panel CPU
detects keys and sends data communication contents
through the MIC Jack to the Main CPU. The Panel CPU re-
ceives commands from the Main CPU and controls the dis-
play system.
The LCD operates with 1/9 duty under the LCD driver
(IC903) control. The LCD and KEY Backlights are controlled
by Q909. The display brightness of the LCD Backlight can be
changed.
Q910
IC901
8C
AVR
PSW
POWER
SW
RED
TX/Busy
LED
GRN
SB
RST2
SHIFT
PSENS
RXD, TXD
MIC, ME
SPO
GND
Fig. 7 TK-7180H Display circuit
CIRCUIT DESCRIPTION
IC903
LCD LCD
driver
Mask
Q909
ROM
BLC1
LCD KEY
back back
DIMM
light light
IC902
CPU
Function
FKEY [1~10]
KEY
SB
MIC
HK, PTT, DM, BLC2
jack
7-2. TK-7182H Transceiver
The display unit consists of the LCD driver (IC902), the TX/
BUSY LED, the KEY detection, the Backlight and the Micro-
phone jack circuits.
The LCD driver performs serial communication with the
Main CPU (IC404) on the TX-RX unit (B/3) and the LCD driver
detects keys and sends data to the Main CPU. The LCD
driver receives commands from the Main CPU and controls
the display system.
The LCD operates with 1/4 duty under the LCD driver
(IC902) control. The LCD and KEY Backlights are controlled
by Q908. The display brightness of the LCD Backlight can be
changed by Q909.
SB
8C
PSW
POWER
SW
Function
KEY
TX/Busy
LED
Q902
LCDDO
LCDCS
LCDCLK
LCDDI
SPO
SP
GND
Fig. 8 TK-7182H Display circuit
TK-7180H/7182H
IC901
AVR
LCD
KS [5,6]
KI [1~5]
Q908
RED
IC902
LDC
LCD
DIMM
driver
back
GRN
light
BLC
PTT, ME, MIC, HOOK, DM
KEY
back
light
SB
J901
MIC
jack
SP
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