Icom IC-M412 Service Manual page 16

4-5 CPU (LG; IC1) PORT ALLOCATION
Pin No. LINE
3 PSTB Strobe signal to the PLL IC (M: IC1).
4 PCK Clock signal to the PLL IC (M: IC1).
5 PDATA Serial data to the PLL IC (M: IC1).
6 PSPS Power control signal to the PLL IC (M: IC1) for RX VCO loop. (GND level)
7 PMPS Power control signal to the PLL IC (M: IC1) for TX/CH70-RX VCO loop. (GND level)
12 PTT [PTT] key input. (pulled up)
21–23 DIM1–3 Brightness (Dimmer) control signals to the LED driver (LG: Q1–3).
30 DOWN [DWN] key input. (pulled up)
31 UP [UP] key input. (pulled up)
32 CH16 [CH16] key input. (pulled up)
33 SCAN [SCAN] key input. (pulled up)
34 CH [CH] key input. (pulled up)
35 CLR [CLR] key input. (pulled up)
36 MENU [MENU] key input. (pulled up)
37 ENT [ENT] key input. (pulled up)
38 LCDCLK Clock signal (25 kHz) to the LCD driver (LG: IC8).
TX power control signal to the TX power SW (M: Q16).
39 H/L
"H"= When the TX power is 'high.'
41 DSDEC Decoded DSC signal from the DSC decoder (M: IC15).
PLL unlock signal from the PLL IC (M: IC1).
42 UNLK
"L"= When the PLL is unlocked.
53 NMRXD NMEA data (4800 bps) from photo-coupler (LG: IC5).
54 ECK Clock signal to the EEPROM (LG: IC3).
55 EDATA Data I/O port for EEPROM (LG: IC3).
• RX (MAIN-RX)
Tuning voltage to the tuned BPF (M: D26–28) via buffer (LG: IC2).
57 DS/BPFV
• TX
DSC encode signal to the LPF (M: IC8).
58 BEEP Beep sounds (500, 750, 1k, 1.3k and 2.2 kHz square waves).
61 SQLV [SQL] dial input. (divided voltage of 5V line)
62 SQL Noise level from the IF IC (M: IC2) via noise AMP (M: IC11).
63 LBAT Power supply voltage detect (voltage of VCC line divided by R36 and R37(LG)).
64 TXDET TX power detect (rectifi ed voltage from TX power detector (M: D12, 13)).
65 KEYM Key detect signal (devided voltage) from the HM-164.
TX mute signal to the TX mute controller (M: Q17, 18).
70 TMUTE
"H"=TX mute.
MIC mute (MIC line disconnect) signal to the MIC mute SW (M: IC5).
71 MICM
"L"=MIC mute (=in RX).
Power line control signal to the T5 line controller (M: Q57, 58).
72 SEND
"H"=T5 line is active (=in TX).
RX AF mute control signal to the AF mute SW (M: IC4).
73 RMUTE
"L"=AF mute (squelch close).
Power line control signal to the R5 line controller (M: Q53, 54).
74 RCV
"H"=R5 line is active (=in RX).
78 LCE Strobe signal to the LCD driver (LG: IC8).
79 LSCL Clock signal to the LCD driver (LG: IC8).
80 LSI Serial data to the LCD driver (LG: IC8).
DESCRIPTION
4 - 10
I/O
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