Port Allocations; Bfo Circuit - Icom IC-M700PRO Servise Manual

3-3-3 2ND LO AND REFERENCE OSCILLATOR
CIRCUITS
The reference oscillator (X3001) generates 30.0 MHz fre-
quency used for the both DDS ICs as a system clock and
for the LO output. The oscillated signal is doubled at the
driver (Q3002) and picked up the 60 MHz frequency at
the resonator circuit (L3004, L3005). The 60 MHz signal is
applied to the MAIN unit as a 2nd LO signal.

3-3-4 BFO CIRCUIT

The DDS IC (IC3002) generates a 10-bit digital signal
using the 30 MHz system clock. The digital signal is con-
verted to an analog wave signal at the D/A converter (R3120
–R3139). The analog wave is passed through the low-pass
filter (L3037, L3038, C3154–C3158), and is then applied
to the MAIN unit as the BFO signal. The PA unit separate
grounding from the other units to obtain floating.

3-4 PORT ALLOCATIONS

CPU (MAIN unit; IC132)
Pin Port
number name
Input port for the CPU reset signal.
RES When receiving a "LOW" pulse, the
1
CPU is reset.
Data input port from the sub CPU in
RXDO
10
the FRONT unit.
Data output port to the sub CPU in
TXDO
11
the FRONT unit.
Input port to the sub CPU in the
NSEN
16
FRONT unit.
Outputs low power control signal for
POC2
17
60 W power.
Outputs low power control signal for
POC1
18
20 W power.
Input port for the CW keying.
CWIN
20
Outputs a "SEND" control signal for
ASEN
21
the ACC (1) and ACC (2) sockets.
Outputs a "SEND" control signal for
CSEN T8 and R8 voltage line control.
22
Outputs an alarm control signal to
activate the 2-tone emergency alarm
ALMS
23
encoder.
Outputs a tone switching signal for the
ALMC 2-tone emergency alarm encoder.
24
Outputs a clock signal for the
SCL
25
EEPROM (IC134).
Data bus line for the EEPROM
SDA
26
(IC134).
Outputs a serial signal for the
SO
27
EEPROM (IC135).
Data bus line for the EEPROM
SDA
28
(IC135).
RSM Input port for the S-meter indication.
30
MFOR Input port for the RF-meter indication.
31
Input port for the antenna current
meter indication for [EUR] version.
ANTC The ANTC signal can be received
32
when an optional AT-130E is con-
nected.
Input port for the squelch detected
SQLS signal.
33
Input port for the transmit/receive
TRC
34
switching signal.
Input port for the scan control signal
SCAS
35
from the ACC (1) socket.
Outputs RF gain control signal to the
RFG
36
AGC circuit.
3 - 6
Description
High: When key is closed.
Low : For transmit.
High : Alarm ON.
High : High tone.
High : When squelch is open.