Icom IC-F4021T Service Manual

Also see for IC-F4021S: Instruction manual Instruction manual Instruction manual

Contents

Icom IC-F4021T Service Manual Manual pdf 13 page image

5 - 65-5-1 CPU (IC22)PinNo.PortName Description1−3 KR1−KR3 Input ports for dealer-programmable keys.4−8 KS0−KS4 Output ports for dealer-programmable keys.9 BUSY Outputs “BUSY” signal to the DSP UNIT.10 CCS Outputs chip-select signal to the DSP UNIT.11 SCK Outputs serial clock signal to the PLL IC (IC2, pin 9)and D/A converter (IC12, pin 7/IC23, pin 7).19−21CENC0−CENC2 Output ports for CTCSS/DTCS signal.22 S5COutputs S5V line control signal to the S5Vregurator (Q23).“Low”=While power save mode.26 T5COutputs T5V line control signal to the T5V lineregurator (Q24, Q49).“Low”=While transmitting.27 R5COutputs R5V line control signal to the R5V lineregurator (Q25).“Low”=While receiving.31 PLST Outputs PLL strobe signal to the PLL IC (IC2, pin 11).34 ULCKInput port for PLL unlock detect signal from thePLL IC (IC2, pin 7).“Low”=While the PLL circuit is unlocked.35 TMUTOutputs transmit mute signal to the transmit muteswitch (Q46).“High”=Transmitting is muted.36 MONI Input port for [SIDE1] key (S5).“Low”=While the key is pushed.37 EMER Input port for top switch (S1).“Low”=While the switch is pushed.39 DSDA Outputs serial data to the D/A converter (IC23, pin 6).43 SENC Outputs DTMF signals to the LPF (IC6, pin 3).44 BEEP Outputs beep sounds to the D/A converter (IC12,pin 21).45 SDEC Input port for DTMF signals.46 CDEC Input port for CTCSS/DTCS signals.48 BATV Input port for remaining battery power.49 LVIN Input port for VCO lock voltage.50 RSSI Input port for receive signal strength level signalfrom the FM IF IC (IC9, pin 12).59 RESInput port for CPU reset signal from the reset IC(IC8, pin 1).“Low”=When the CPU is reset.69 CSFT Outputs CPU clock shift signal to the clock shiftswitch (D6).70 AFONOutputs AF power amplifi er (IC15) control signal tothe AF power amplifier controller (Q41, Q42, D21,D23).“High”=The AF power amplifi er is ON.71 DAST Outputs strobe signal to the D/A converter (IC12,pin 6).72 DUSEOutputs CTCSS/DTCS select signal to the tonefi lter switch (Q40).“High”=While DTCS is in use.75 NOIS Input port for noise signal from the FM IF IC (IC9,pin 13).82 ESDA Outputs serial data to the EEPROM (IC10, pin 5).85 ESCL Outputs clock signal to the EEPROM (IC10, pin 6).PinNo.PortName Description89 DIGIOutputs Analog/Digital select signal to the A/Dswitch (D2, D3).“High”=Digital mode is selected.91 LSO Outputs serial data to the LCD driver (IC20, pin 48).92 LSCK Outputs clock signal to the LCD driver (IC20, pin 47).93 LCS Outputs chip-enable signal to the LCD driver (IC20,pin 46).94 LINH Outputs display inhibit signal to the LCD driver(IC20, pin 45).95 LIGTOutputs LCD backlight control signal to thebacklight LED’s (DS1, DS2) driver (Q45).“Low”=While the backlight is ON.96 RMUTEOutputs AF mute signal to the analog switch (IC3,pins 12, 13).“Low”=While the squelch is close or transmitting.97 MMUTEOutputs MIC signals mute signal to the analogswitch (IC3, pin 5) and MIC mute switch (Q31).“Low”=While receiving.99 SSO Outputs serial data to the PLL IC (IC2, 10) and D/Aconverter (IC12, pin 8).100 KR0 Input ports for dealer-programmable keys.5-5-2 D/A CONVERTER (IC12)PinNo.PortName Description2 MCGO Outputs level-adjusted MIC signals to the MIC muteswitch (Q31).10,16 MOD Outputs modulation signal to the modulation circuits(D2).14 REF Outputs reference frequency control voltage to thereference frequency oscillator buffer (IC7, pin 13).15 BAL Outputs modulation balance control signal to thereference frequency oscillator buffer (IC7, pin 12).22 BEEPO Outputs beep sounds to the AF volume buffer (IC6,pin 9).23 SQLC Outputs level-adjusted AF signals to the noise filter(IC9, pins 7, 8, R42, R44−R46, C69, C70, C413).5-5-3 D/A CONVERTER (IC23)PinNo.PortName Description1 T1• While receivingOutputs BPF tuning voltage to the tunable BPF(D19, D25, L7, L8, C21−C23, C25, C27−C29).• While transmitting (as “APC” signal)Outputs transmit mute signal to the transmit muteswitch (Q46).2 T2Outputs BPF tuning voltage to the tunable BPF( D14, D15, L9, L11, C19, C36, C39−C41,C44, C45 ).3 TXLVA Outputs oscillating frequency adjust voltage to theTX VCO ( Q16, D10, D13).4 RXLVA Outputs oscillating frequency adjust voltage to theRX VCO ( Q17, D9, D11).5-5 PORT ALLOCATIONS