Icom ic-r20 Service Manual page 68

4-5-2 SUB CPU PORT ALLOCATIONS
(REC UNIT; IC2)
Pin Port
number name
18 RSTO Input port for the USB reset signal.
19 PWREN Input port for the USB suspend signal.
Outputs recording/playing select sig-
FIFOST
24
nal.
Input port for the ADPCM command
25 CBUSY
waiting signal.
EMP
Input ports for the ADPCM buffer sig-
26–28 MID
nals.
FUL
35 B_SQL
Output recording mute signals.
36 A_SQL
Input port for the power supply verify-
25 SUB_3C
ing signal.
4-5-3 EXPANDER IC PORT ALLOCATIONS
(RF UNIT; IC22)
Pin Port
number name
Outputs the down converter control
4 DOWN_CONV
signal.
Outputs 2002 MHz LO select signal for
2GLO
5
the down converter.
Outputs 1001 MHz LO select signal for
6 1GLO
the down converter.
Outputs the bar antenna select signal.
7 ANTSW
High : The bar antenna is selected.
Outputs the power save control signal
to the A-BAND circuit.
11 APS
Low : While the A-BAND circuit is
Outputs WFM mode select signal at
A_WFM
12
the A-BAND circuit.
NBC Outputs noise blanker control signal.
13
Outputs the power save control signal
to the B-BAND circuit.
14 BPS
Low : While the B-BAND circuit is
Description
Description
power saving.
power saving.
4-5-4 D/A CONVERTER IC PORT ALLOCATIONS
(RF UNIT; IC14)
Pin Port
number name
A_VHFC
2
3 A_300MC
4 A_UHFC
A_VCO3
6
7 A_NFMC
13 A_ANLC
18 A_AMC
19 SSBC
4-5-5 D/A CONVERTER IC PORT ALLOCATIONS
(RF UNIT; IC20)
Pin Port
number name
B_VHFC
2
3 B_UHFC
4 B_GC
B-800MC
5
7 A_WFMC
8 B_VCO1
B_ANLC
9
18 A_AMC
B_AM_FM
19
4 - 13
Description
Outputs VHF band selecting signal at
the A-BAND circuit.
Outputs 300 MHz band selecting sig-
nal at the A-BAND circuit.
Outputs UHF band selecting signal at
the A-BAND circuit.
Outputs the A-BAND 1st LO circuit
control signal.
Outputs narrow FM mode selecting
signal at the A-BAND circuit.
Outputs ANL (Automatic Noise Limiter)
control signal at A-BAND circuit.
High : While ANL is ON.
Outputs AM mode selecting signal at
the A-BAND circuit.
Outputs narrow SSB mode selecting
signal at the A-BAND circuit.
Description
Outputs VHF band selecting signal at
the B-BAND circuit.
Outputs UHF band selecting signal at
the B-BAND circuit.
Outputs GHz band selecting signal at
the B-BAND circuit.
Outputs 800 MHz band selecting sig-
nal at the B-BAND circuit.
Outputs wide FM mode selecting sig-
nal at the B-BAND circuit.
Outputs the B-BAND 1st LO circuit
control signal.
Outputs ANL (Automatic Noise Limiter)
control signal at B-BAND circuit.
High : While B-BAND ANL is ON.
Outputs AM mode selecting signal at
the B-BAND circuit.
Outputs narrow AM or narrow FM
mode selecting signal at the B-BAND
circuit.