Power Supply Circuits; Port Allocations - Icom IC-4088E Service Manual

4-4 POWER SUPPLY CIRCUITS

VOLTAGE LINE
LINE
The voltage from the connected battery or
VCC
power supply from DC IN (J302).
Common 3 V converted from the VCC line at the
3V regulator circuit (IC303). The circuit outputs
CPU3V
the voltage regardless of the power ON/OFF
condition.
Common 3 V converted from the VCC line at the
+3V
+3V regulator circuit (Q303, D301).
Receive 3 V cotrolled by the R+3 regulator cir-
R+3
cuit (Q304) using the "RXV" signal from the CPU
(IC301).
Transmit 3 V converted from the VCC line at the
T+3 T+3 regulator circuit (Q305, Q308, D303, D304)
using the "TXV" signal coming from the CPU
(IC301).

4-5 PORT ALLOCATIONS

4-5-1 D/A CONVERTER (RF unit; IC3)
Pin Port
number name
Outputs deviation control signal.
1 MODC
Outputs TX power control signal.
2 PWRC
Outputs PLL reference frequency con-
3 FC
trol signal.
4-5-2 CPU (MAIN unit; IC1)
Pin Port
number name
Input port for the test mode switch.
27 TEST
Outputs the clock signal to the EEP-
31 EEPCK
ROM (MAIN unit; IC300).
Outputs data signals to the EEPROM
32 EEPDA
(MAIN unit; IC300).
Input port for the control signal of the
33 DETOUT
tone detection
Outputs the shift control signal to the
35 SHIFT
PLL IC (RF unit; IC2).
Outputs strobe signals for the PLL IC
36 PLSTB
(RF unit; IC2).
Outputs the clock signal to the PLL IC
37 CK
(RF unit; IC2).
Outputs data signals to the PLL IC (RF
38 DATA
unit; IC2).
DESCRIPTION
Description
Description
Pin Port
number name
Input port for the PLL unlock signal from
the PLL IC (RF unit; IC2).
41 UNLK
Input port for the PTT switch from the
external mic jack (MAIN unit; J303).
42 PTT
Input port for the control signal from the
43 MICIN
external remote microphone.
Input port for the transceiver's internal
44 TEMP
temperature.
Input port for the squelch level signal.
46 SQLIN
Input port for connected battery pack
47 VIN
voltage.
Input port for the [MODE] switch.
51 MODE
Input port for the [POWER] switch.
52 POWSW
Outputs beep audio signal.
53 BEEP
Input port for the [DOWN] switch.
54 DOWN
Input port for the [UP] switch.
55 UP
Input port for the internal [PTT] switch.
56 PTTSW
pushed.
Outputs the control signal of LCD back
57 LAMPO
light.
Outputs the control signal of the AF
amplifier regulator circuit (MAIN unit;
58 AFON
Q306, Q307, Q311).
Outputs the control signal of the R+3
59 RXV
regulator circuit (MAIN unit; Q304).
Outputs the [MIC] mute signal for RING
function.
61 MMUTE
Outputs internal microphone control
signal.
62 MICSW
Outputs the control signal of the +3V
regulator circuit (MAIN unit; Q303,
63 POWER
D301).
Outputs the control signal of the vol-
ume mute switch (MAIN unit; Q316).
64 RMUTE
Outputs the control signal of the T+3
regulator circuit (Q305, Q308, D303,
65 TXV
D304).
Outputs the control signal of the charge
66 CHGC
circuit (Q312, Q314, D305, D308).
4 - 3
Description
Low : During unlock.
Low : External PTT switch is ON.
Low : While the [POWER] switch is
pushed.
Low : While the [PTT] switch is
High : While RING signals are out-
put, etc.
High : While the internal PTT switch
is pushed.
High : While squelched.