Port Allocations - Icom ic-r20 Service Manual

4-5 PORT ALLOCATIONS

4-5-1 MAIN CPU PORT ALLOCATIONS
(LOGIC UNIT; IC3)
Pin Port
number name
3 DATAC Outputs data and clock control signal.
8 CLS1
Output clock shift signals.
9 CLS0
Input port for the detecting signal
whether the external power supply is
HVDET connecting or not.
46
Low : The external power supply is
Outputs control signal to the AF ampli-
17 AFON
fier.
18 POWER Input port for [POWER] key.
Outputs B-band mute control signal.
19 B_AMUTE
High : While B-band is muting.
Outputs A-BAND de-emphasis control
20 A_AF_THURU
signal.
A_DUD
A_DCK
21–24 Input ports for [A-DIAL]/[B-DIAL].
B_DUD
B_DCK
Input port for [SQL] switch.
25 SQL
Low : While [SQL] switch is pushed.
Outputs REC unit regulator control sig-
26 SUB_3C nal.
High : While recording or playing.
Outputs A-BAND's 1st LO control sig-
31 A_VCO1
nal.
34 VRSTR Outputs strobe signals for volume.
36 REC Outputs recording LED control signal.
Outputs charging current control sig-
CHGS nal.
38
High : While rapid charging.
Outputs charger circuit control signal.
39 CHGC
High : While charging.
40 +3S Outputs +3S regulator control signal.
Outputs LCD back light control signal.
41 LIGHT
Low : Lights ON.
Outputs strobe signals to the expander
LD1
42
IC (RF unit; IC14, pin 15).
Outputs BAND2 selecting signal in the
43 B2C
HF band.
Outputs BAND3 selecting signal in the
44 B3C
HF band.
Outputs BAND1 selecting signal in the
B1C
45
HF band.
Outputs HF band selecting signal at A-
46 HFC
BAND.
47 PLLDATA Outputs data signal to the PLL IC.
Description
connected.
(LOGIC unit; IC3)–Continued
Pin Port
number name
48 STR2
49–52 KS3–KS1
I1
53
PCON
L0
54
B_TCON
KR5–KR0
55–61
B_AF_THURU
63
64 PLLASTB
65 PLLCSTB
PLLESTB
66
67 A_R3C
PLLCK
68
PLLDSTB
69
70 PLLBSTB
71 A_TCON
72 LCD_CS
74 BFOC
75 B_R3C
76 LCD_RESET
77 LCD_RS
78 LD2
B_VCO2
79–81 B_VCO3
B_VCO4
98 ECK
99 ESIO
4 - 12
Description
Outputs strobe signal to the D/A con-
verter IC (IC22, pin 1).
Output key matrix signals.
• Input port for the matrix signal.
• Outputs power ON/OFF control sig-
nal.
• Input port for the matrix signal.
• Outputs B-RTONE filter amplifier
control signal.
Input ports for key matrix
Outputs B-BAND de-emphasis control
signal.
Outputs strobe signals to the A-BAND
1st LO circuit.
Outputs strobe signals to the A-BAND
2nd LO circuit.
Outputs strobe signals to the DOWN
CONVERTER LO circuit.
Outputs A-BAND power supply circuit
control signal.
Low : While A-BAND receiving.
Outputs clock signal to the PLL IC.
Outputs strobe signals to the B-BAND
2nd LO circuit.
Outputs strobe signals to the B-BAND
1st LO circuit.
Outputs A-RTONE filter amplifier con-
trol signal.
Outputs LCD chip select signal.
Outputs BFO control signal.
Low : While SSB is receiving.
Outputs B-BAND power supply circuit
control signal.
Low : While B-BAND receiving.
Outputs reset signal to the LCD.
Outputs command and data signals to
the LCD.
Outputs strobe signals to the expander
IC (RF unit; IC20, pin 15).
Output B-BAND 1st LO circuit control
signals.
Outputs clock signal to the EEPROM
(IC1, pin 6).
I/O port for data signal from/to the
EEPROM (IC1, pin 5).