Key / Power Switch Board - Philips LX700/21S/22S/25S Service Manual

5-1
KEY / POWER SW BOARD
TABLE OF CONTENTS
IC Interbnal Block Diagram ............................................. 5-1
Circuit Diagram ................................................................ 5-2
PCB Layout Top & Bottom View ...................................... 5-3
Electrical Parts List .......................................................... 5-4
CF745 INTERNAL BLOCK DIAGRAM
9-11
9-11
EPROM/ROM STACK 1
512 X 12 TO
STACK 2
2048 X 12
PC
12
INSTRUCTION
REGISTER
WDT TIME
9
OUT
12
8
INSTRUCTION
DECODER
DIRECT ADDRESS
DIRECT RAM
ADDRESS
8
STATUS
W
ALU
FROM W
4
"TRIS 5"
TRISA
PT6311 INTERNAL BLOCK DIAGRAM
D
IN
Serial
D
OUT
Data
CLK
interface
STB
V
DD
R
OSC
OSC
SW 1
Genaral
SW 2
Input
SW 3
Register
SW 4
LED 1
LED 2
LED
LED 3
Driver
LED 4
LED 5
5-1
T0CKI
OSC1 OSC2 MCLR
CONFIGURATION WORD
PIN
"DISABLE" "OSC
SELECT"
WATCHDOG
2
TIMER "CODE
PROTECT" OSCILLATOR/
TIMING &
CONTROL
CLKOUT
WDT/TMR0
PRESCALER
"SLEEP"
6
"OPTION"
OPTION REG.
GENERAL
FROM W
PURPOSE
5
REGISTER
FILE
5-7
(SRAM)
24, 25, 72 or
73 Bytes
TMR0 FSR
DATA BUS
8
FROM W
FROM W
4 8
8 8
"TRIS 6" "TRIS 7"
TRISB PORTB
PORTA TRISC PORTC
4
8
RC<7:0>
RA<3:0> RB<7:0>
(28-Pin
Devices Only)
SG1/KS1
Control
SG2/KS2
SG3/KS3
SG4/KS4
Genaral SG5/KS5
Segment
Input Driver/ SG6/KS6
Register
SG7/KS7
SG8/KS8
SG9/KS9
Grid
SG10/KS10
Driver/
SG11/KS11
Timming
SG12/KS12
Generator
SG13/GR16
SG14/GR15
Key Scan
SG15/GR14
Output
SG16/GR13
Key Matrix
SG17/GR12
Memory
SG18/GR11
SG19/GR10
SG20/GR9
GR1
GR2
GR3
Grid
GR4
Driver
GR5
Dimming
GR6
Circuit
GR7
GR8
K1 K2 K3 K4 VDD GND VEE
8
8
8