Icom IC-2820H Service Manual page 15

4-5 CPU PORT ALLOCATION
PIN
PORT NAME
No.
Cut-off frequency shifting signal to the HPF
3 AN
(IC48).
Cut-off frequency shifting signal to the HPF
4 DA_SEL
(IC48).
MIC mute signal to the MIC mute switch (IC30).
5 MM_MUTE
"H"=MIC mute.
ALC amplifier control signal tot the AF
6 DCONT switches (IC29 and IC52).
"H"=ALC amplifi er ON.
2nd IF filter (Right band; Wide/Narrow)
7 R_WN_SEL toggling signal.
"H"=Narrow. "L"=Wide.
Microphone sensitivity select signal.
11 MIC_SENC
"H"=High sensitivity.
M o d u l a t i o n l i n e sw i t c h i n g s i g n a l t o
17 MOD_DA t h e M O D s e l e c t o r ( L e f t b a n d ; I C 9 ) .
"H"=Modulation enable.
M o d u l a t i o n l i n e sw i t c h i n g s i g n a l t o
18 MODSEL the MOD selector (Right band; IC63).
"H"=Modulation enable.
Strobe signal to the PLL IC (Right band;
21 R_PLLSTB
IC14).
Strobe signal to the PLL IC (Left band;
22 L_PLLSTB
IC41).
AM-demodulator circuit (Left band) control
signal.
23 L_AMC
"H"=AM mode (AM-modulator circuit is
activated).
Tone filter switching signal to the LPF
24 DTCS_SEL (Q100).
"H"=DTCS mode. "L"=CTCSS mode.
RX circuits (Left band) control signal.
25 L_R5C
"H"=RX circuits (Left band) is activated.
2nd IF filter (Wide/Narrow) toggling
26 L_WN_SEL signal.(Left band)
"H"=Narrow. "L"=Wide."
Modulation mute signal to the MOD
27 UMMUTE m u t e s w i t c h ( R i g h t b a n d ; Q 6 4 ) .
"H"=Modulation muted.
Transmitting control signal to the VT8
28 UTX_C
regulator (Q12, 15).
VCO oscillating frequency shift signal to
29 L_VCO_SHIFT
the Left band VCO.
Lock-up time control signal to the loop fi lter
30 R_PLLSW (Right band).
"H"=Fast lock-up time.
PLL unlock signal from the PLL IC (Right
31 R_UNLOCK
band; IC14).
Clock signal to the PLL ICs (Right band;
IC14, Left band; IC41).
32 PLLCK
(Commonly used for both of the Left and
Right bands.)
Data to the PLL ICs (Right band; IC14, Left
band; IC41).
33 PLLDATA
(Commonly used for both of Left and Right
bands.)
PLL unlock signal from the PLL IC (Left
34 L_UNLOCK
band; IC41).
Modulation mute signal to the MOD
35 VMMUTE m u t e s w i t c h ( L e f t b a n d ; Q 1 0 9 ) .
"H"=Modulation muted.
Transmitting control signal to the UT8 regulator
36 VTX_C (Q13, 17).
"H"=While transmitting.
Lock-up time control signal to the loop fi lter
37 L_PLLSW (left band).
"H"=Fast lock-up time.
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DESCRIPTION I/O
O
O
O
O
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4 - 9
PIN
PORT NAME
No.
VCO power control signal to the VCO
38 R_UVCO_SEL select switch (Right band UHF; Q65, 68).
"L"=Right band TX/RX VCO is activated.
VCO power control signal to the VCO
39 R_VVCO_SEL select switch (Right band VHF; Q65, 68).
"L"=Right band RX VCO is activated.
LO filter switching signal to the LO
40 L_LO_SW
regulator (Q106).
AF line switching signal to the AF switch
42 R_DA_SEL
(IC12).
Switching signal to the AF filter (Right
42 R_AFFIL_SEL
band; Q48).
AF line switching signal to the AF switch (IC16).
43 R_DET_MUTE
"H"=AF mute.
AF line switching signal to the AF switch
44 L_DA_SEL
(IC11).
AF line switching signal to the AF switch (IC13).
45 L_DET_MUTE
"H"=AF mute.
48 D5VC Power control signal for the optional unit.
AF mute signal to the SP mute switch (Right
51 R_AF_MUTE band; Q101).
"H"=AF mute.
Switching signal to the AF fi lter (Left band;
52 L_AFFIL_SEL
Q47).
53 DA3STB Strobe signal to the D/A converter.
53 DA2_STB Strobe signal to the electric volume.
55 DTCS DTCS signal.
56 DTMF DTMF signal.
57 MIC_SEL Connected microphone detect signal.
61 DTMSTB Strobe signal to the DTMF decoder (IC56).
62 MICUD [UP]/[DWN] key input.
W h i l e r e c e i v i n g ; i n p u t s R S S I
s i g n a l ( I C 1 8 ; R i g h t b a n d ) .
63 R_RSLV
While transmitting; inputs Lock Voltage
from the PLL IC (IC14).
While receiving; inputs RSSI signal
f r o m I F I C l ( I C 1 5 ; L e f t b a n d ) .
64 L_RSLV
While transmitting; inputs Lock Voltage
from the PLL IC (IC41).
Current level from the current detector
65 IDET
(IC55, Q164).
Demodulated Weather alert signal from the
66 R_WXALT
WX fi lter (Q47). [USA] only
Demodulated DTCS signals from the
68 R_DTCS_IN
CTCSS fi lter (Q42).
Demodulated Weather alert signal from the
69 L_WXALT
WX fi lter (Q48). [USA] only
Demodulated DTCS signals from the
70 L_DTCS_IN
CTCSS fi lter (Q41).
Transceiver's internal temparature from the
71 TEMP
thermal detector circuit (R509).
I/O port for clock signal to the EEPROM
76 SCL
(IC22).
Serial clock signal to the electric volume
77 AF_VOL_CK
IC.
78 AF_VOL_DATA Data signal to the electric volume IC.
Latch enable signal to the electric volume
79 AF_VOL_STB
IC.
80 AF_VOL_RES Reset signal to the electric volume IC.
Power control signal to the PWR controller
80 PWR (Q82).
"H"=While the power is ON.
82 SDA Data signal to the EEPROM (IC22).
DESCRIPTION I/O
O
O
O
O
O
O
O
O
O
O
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O
I
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I
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I/O
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I/O