Kenwood TH-K20A Service Manual

TH-K20A/K20E
7
SEMICONDUCTOR DATA
MCU: R5F2L3ACCKEKA (TX-RX unit IC401 )
Pin No. Port Name I/O Function
1 KEYIT I Type detection
2 KEYIS I Type detection
3 HSDO O DTMF/BEEP/1750Hz tone output
4 LSDO O CTCSS/DCS tone output
5 WKUPO - Ground
6 VREF - Reference voltage input
7 MODE - MCU mode select
8 XCIN - Not used (Pull-up)
9 XCOUT - Not used
10 RESET I MCU reset
11 XOUT O 11.0592MHz MCU clock output
12 VSS - Ground
13 XIN I 11.0592MHz clock input for MCU
14 VCC - 5V power supply (5M)
15 BSFT O Beat shift control
16 INPTT I
INT PTT switch input
L: Active
17 5RC O
5R RX power switch control
L: Active
18,19 ENC2-ENC1 I Encoder input 2,1
20 RxD I Serial data input from PC
21 TxD O Serial data input to PC
22 W/N O
Wide/Narrow control
H: Narrow
23 PLLE O
PLL-IC enable
H: Active
24 PLPS O
PLL-IC save control
L: Save ON
25 PLLD I
PLL unlock detect
L: Unlock
26 EXPTT I
EXT-PTT input
L: Active
27 LAMP O
BacKlight LED control
H: Lights
28 NC O Not used
29 E2PCS O
EEPROM chip select
L: Active
30 E2PIN I Data input from EEPROM
31-34 COM0-COM3 O
LCD common output
H: Active
35-66 SEG0-SEG31 O
LCD segment output
H: Active
67 LEDR O
TX LED (Red) control
H: Lights
68 LEDG O
BUSY LED (Green) control
H: Lights
69 5VC O
5V MIC AMP power switch control
L: Active
70 5MSC O
5MS main power switch control
L: Active
71 SPM O
Speaker mute control
L: Mute
Pin No. Port Name I/O Function
72 MONI I
[MONI] key switch input
L: Active
73 CLK O Common serial clock output
74 DATA O Common serial data output
75 5CC O
5C Common power switch control
L: Active
76 5TC O
5T TX power switch control
L: Active
77 VOLCS O
DAC-IC chip select
L: Active
78 VDCSW O
Voltage discharge control
H: Active
79 CURRENT I TX current detect
80 VOX I VOX level detect
81 REM I
Remote control microphone key
detect
82 BATT I Battery voltage detection
83 THERM I Temperture detect
84 RSSI I RSSI level detect
85 SQL I Squelch level detect
86 LSDI I CTCSS/DCS tone detect
87 CVDET I VCO controle voltage detect
88-90
KEYO4-
KEYO2
O Key matrix output 4-2
91-93 VL1-VL3 - LCD drive power supply
94 SHIFT O
VCO TX/RX control
H: TX
95 KEYO1 O Key matrix output 1
96 VL4 - LCD drive power supply
97-100 KEYI1-KEYI4 I Key matrix input 1-4

Kenwood TH-K20A Specifications

General

Brand	Kenwood
Model	TH-K20A
Category	Transceiver
Language	English