Icom IC-R8500 Service Manual page 16

4-4-2
SUB CPU
(DISP UN!T,
IC1)
Pin Port
Description
number
name
1
APFV
Input port
for
the [APF]
control.
9
RES
Input port
for
reset
signal.
22
SCL
Outputs clock signal
to
the
EEPROM
(IC6).
23
SDA
Outputs data
signal
to
the
EEPROM
(IC6).
24
DIM
Outputs
dimmer
control signal.
"High": Bright
25
REC
Outputs
REC REMOTE
control signal.
"High":
While squelch
is
opened.
77-80
P10-P13
Outputs key matrix
signal to
the
SW-B
board.
81
MET
Outputs meter drive signals
in
14
bit
PWM
wave.
82
MDA
Input port
for
the [DIAL].
83,
84
PI
6.
P17
Outputs key
matrix signal to the
SW-A
board.
86
MTXD
Input port for data signal
from the
CPU
(MAIN
unit,
IC33).
87
MRXD
Outputs data signal
for
the
CPU
(MAIN
unit,
IC33).
88
MDB
Input port
for
the [DIAL].
,
90-96
PBC^
PB6
Input ports for key matrix.
97
AN7
Input port
for
the [AF GAIN].
98
AN8
Input port
for
the
[SQUELCH].
99
DELV
Input port for
the
[DELAY/SPEED].
100
SFTV
Input port
for
the
jlF
SHIFT).
4-4-3
[
3DS
ETC-LATCH
{PLL
UNIT,
IC3)
Pin
number
Port
1
name
Description
68
FIL4
Outputs
768
MHz
2 nd
LO
bandpass
filter
select
signal.
69 FIL3
Outputs
256
MHz
2nd
LO
bandpass
filter
select signal.
70
VU
Outputs
bandpass
tilter*select
signal.
"Low"
:
While
receiving
RF
signals
above 30 MHz.
71
HF
Outputs bandpass
filter
select
signal.
"Low"
:
While receiving
RF
signals
below
30 MHz.
72
VC04
Outputs
VCO
(VCO-B
board. Q3)
select
signal.
73
VC03
Outputs
VCO
(VCO'B
board. Q1)
select signal.
74
VC02
Outputs
VCO
(VCO-A
board. Q3)
select signal.
75
VC01
Outputs
VCO
(VCO-A
board. Q1)
select signal.
4-4-4
I/O
EXPANDER
ICs
MAIN
unit,
IC15
Port
name
Description
FILC
1
Outputs optional
CW-N
filter
select
signal.
"High":
FL-52A
is
selected.
NBS1
Outputs noise blanker
circuit control
signal.
"High": [NB]
is
turned
ON.
NBS2
Outputs noise blanker
circuit
control
signal.
"High": [NB]
is
turned
ON.
TSW2
Outputs
APF
circuit
control signal.
"High"
:
While
APF
is
activated.
TSW1
Outputs
APF
passband
width control
signal.
"High":
Narrow
is
selected.
1
AGCF
Outputs
AGC
time constant
control
signal.
"High":
AGC
fast
is
selected.
MAIN
unit,
IC16
Port
name
Description
F1
Outputs
bandpass
filter
select signal
to
the
RF-B
unit.
"High":
While
receiving
30
to
89.99999
MHz RF
signals.
F2
Outputs
bandpass
filter
select signal
to
the
RF-0
unit.
"High":
While receiving
90
to
242.09999
MHz RF
signals.
F3
Outputs
bandpass
filter
select signal to
the
RF-B
unit.
"High":
While
receiving 242.1 to
499.99999
MHz RF
signals.
F4
Outputs
bandpass
filter
select signal
to
the
RF-B
unit.
"High":
While
receiving
500
to
1024.99999
MHz RF
signals.
MUTE
Outputs squelch
switch control signal.
"Low"
:
Squelched.
MI5V
Outputs
MI5V
regulator
circuit
control
signal.
"High":
While
receiving
above
30
MHz RF
signals.
FILS
Outputs bandpass
filler
select signal
to
the
MIX
unit.
"High":
266.7
MHz
bandpass
filter is
selected.
SW
Outputs
bandpass
filter
select signal
to
the
RF-B
unit.
"High":
While
receiving
754.1
to
1024.99999
MHz RF
signals.