Power Supply Circuits; Port Allocations - Icom IC-F21 Series Service Manual

4-4 POWER SUPPLY CIRCUITS

VOLTAGE LINE
LINE
HV The voltage from the attached battery pack.
The same voltage as the HV line (battery volt-
VCC age) which is controlled by the power swtich
([VOL] control).
Common 5 V converted from the VCC line by the
+5 regulator circuit (IC10). The output voltage is
CPU5V
applied to the CPU (IC7), reset circuit (IC8) and
etc.
5 V for transmitter circuits regulated by the T5
T5V
regulator circuit (Q27).
5 V for receiver circuits regulated by the R5 reg-
R5V
ulator circuit (Q26).
Common 5 V converted from the VCC line by the
S5V
S5 regulator circuit (Q24, Q19).
The same voltage as the CPU5V line for the ana-
+5V
log swtich (IC6), buffer amplifier (Q13), etc.
The same voltage as the +5V line for the TX-
VCO5V VCO (Q11), RX-VCO (Q10) and buffer amplifiers
(Q5–Q7).
DESCRIPTION

4-5 PORT ALLOCATIONS

4-5-1 CPU (IC7)
Pin Port
number name
7 RES
13 SENC0
14 SENC1
19 SENC2
20 SENC3
23 CENC0
24 CENC1
25 CENC2
28 SCK
29 SO
30 BEEP
36 PLST
37 DAST
38 EXST
39 PTT
40 TXC
41 RLED
42 TLED
43 AFON
44 ESDA
45 CLI
46 CLO
51 F1
52 F2
53 NOIS
54 UNLK
55 TEMP
57 CDEC
58 SDEC
59 RSSI
60 LVIN
4 - 4
Description
Input port for RESET signal.
Outputs single tone encode signal.
Outputs CTCSS/DTCS data signal.
Outputs serial clock signal to the PLL
IC (IC1), EEPROM (IC11), etc.
Outputs data signal to the PLL IC
(IC1) and D/A convertor (IC9).
Outputs beep audio signal.
I/O port for strobe signal from/to PLL
IC (IC9).
• Outputs strobe signal to the D/A con-
vertor (IC9).
• Input port for the initial version sig-
nal.
Outputs strobe signal for the expander
IC (IC15).
Input port for [PTT] swtich signal.
High: While [PTT] switch is pushed.
Outputs TX mute control signal.
High: While transmitting
Outputs BUSY LED control signal.
High: While receiving.
Outputs TX LED control signal.
high: While transmitting.
Outputs control signal for the regulator
circuit of AF power amplifier.
High: While squelch is open, etc.
I/O port for data signal from/to the
EEPROM (IC11).
Input port for cloning signal.
Outputs the cloning signal.
Input ports for the customization key
signals.
Input port for the noise pulse signal for
the squelch function.
Input port for PLL unlock signal.
High: PLL is locked.
Input port for the transceiver's internal
tempereture detection.
Input port for CTCSS/DTCS signals.
Input port for single tone decode sig-
nal.
Input port for the RSSI voltage.
Input port for the PLL lock voltage.