30
TK-690H
(
B
)
CIRCUIT DESCRIPTION
RST
RST
D19
5V
AVR
LCD ASSY
SW
SW
SW
SW
SW
SW
SW
SW
REF
DM1 DM2
DM1 DM2
SB
KEY BACK LAMP
LCD BACK LAMP
S5
PF1
S6
PF2
S7
PF3
S8
PF4
S9
PF5
S10
MON
S11
PF6
S1
POWER
S12
PF7
S13
SCN
S14
PF8
S15
PF9
S2
S3
IC2
RH5VL42C
PTT
HK
D13
RX
D12
TX
IC3
AT24C64N10SI27 EEPROM
AF VR
IC1
NJM78L05UA
ENCODER
SB
HK
ME
MIC
E
TRD
DM
BLC
PTT
MIC
1/2
TRD
RS1
RS2
SB
PS
RST
ED1
IC4
78064GCXXX8EU
Microprocessor
Containing
LCD driver IC
Fig. 11
KCH-11 block diagram
8-2. KCH-11
This display unit consists of a CPU (IC4) a reset IC (IC2),
5V AVR (IC1), EEPROM (IC3), and other components.
• Encoder
Channels are changed by the rotary encoder (ENC). The
up/down pulses from the rotary encoder enter the CPU
(IC4), and converted to a serial data signal, and are sent to
the control unit.
• Power supply
Power is supplied to the CPU by converting SB from the
control unit to 5V by IC1. And SB is supplied for the LED of
backlight.
• CPU
The on/off signals of keys other than the power switch,
and the PTT and HOOK signals, are converted to serial data
and sent to the control unit. Data is displayed on the 14-
digits and 3-digits dot matrix alphanumeric display.
• Dimmer function
From the control of the CPU’s DM1/DM2 port, you can
switch the LCD/KEY backlight, busy/TX LED, or the optional
KMC-28 key backlight as shown in the following table.
Dimmer
LCD
KEY
Busy/TX
KMC-28
setting
H
H
ON
ON
ON
M
M
ON
ON
ON
L
L
ON
ON
ON
OFF
OFF
OFF
OFF
OFF