Icom IC-2SA Service Manual page 12

* OUTPUT PORT
PORT NUMBER
00
ПАМРО)
01
[BUSY LED]
D2
[TONE OUT]
PIN
NUMBER
DESCRIPTION
Becomes "HIGH" when the
backlight LEDs light up.
Outputs a signal for lighting up in
green the transmit/receive
indicator. This port becomes
"LOW" while receiving.
(squelch opens)
Outputs a 1750 Hz tone signal.
(ІС-25Е only)
D3 Outputs an enable signal for the
[TOE] UT-49.
06—09 Outputs а strobe signal for the
[KEYSO~ initial and key matrices and D/A
KEYS3] converter counting signal
©
Š
alternately in an interval.
Outputs clock signals for serial
data.
R00
[SCK]
R01
ПО STB]
Outputs a strobe signal for serial
data to the expander ICs.
Outputs serial data synchronized
R02
[SDATA] with the SCK signal.
R03 Outputs a strobe signal for serial
[PLL STB] data to the PLL IC.
e OUTPUT EXPANDER OO UNIT, ІСТ)
PIN
PORT NUMBER NUMBER DESCRIPTION
Q1 Outputs an AF mute signal for AF
= ОМ) power amplifier.
Outputs a microphone mute
signal. When transmitting a tone
signal, the MIC signal line goes to
ground.
Q3 Outputs a receive mute signal for
[RMUTE] the AF mute circuit. When
emitting а beep tone, this port
outputs the mute signal and the AF
ON port does not output it.
Q4 Outputs a control signal for Т+5 V
[TMUTE] regulator.
Q5 Outputs transmit/receive switching
[SEND] signals. This port becomes
"LOW" while transmitting.
This port becomes "HIGH" while
m the power saver function is
activated.
Q7 12 Outputs a control signal to cut off
[CPC] the loop filter while the power saver
function is activated.
Q8 11 Outputs a mode signal.
[MODE]
Ме MUTE]
* OUTPUT EXPANDER (IO UNIT, ІС2)
PIN
PORT NUMBER NUMBER DESCRIPTION
Q2, 03 Outputs a control signal for the RF
[BA2, BA3] bandpass filter.
13, 14 | Outputs a control signal for the
output power selecting circuit.
This signal is converted into PCON
voltage (APC reference voltage)
using the D/A converter (R2—R6).