NAD C 355BEE Service Manual page 11

AT89S52
KEY BOARD IC73
V
CC
GND
B
REGISTER
PSEN
TIMING
ALE/PROG
AND
EA / V CONTROL
PP
RST
OSC
P0.0 - P0.7
PORT 0 DRIVERS
RAM ADDR.
RAM
REGISTER
ACC
TMP2
ALU
PSW
INSTRUCTION
REGISTER
WATCH PORT 3
DOG LATCH
PORT 3 DRIVERS
P3.0 - P3.7
P2.0 - P2.7
PORT 2 DRIVERS
PORT 0
PORT 2
LATCH
LATCH
STACK
POINTER
TMP1
INTERRUPT, SERIAL PORT,
AND TIMER BLOCKS
PORT 1
LATCH
PORT 1 DRIVERS
P1.0 - P1.7
11
FLASH
PROGRAM
ADDRESS
REGISTER
BUFFER
PC
INCREMENTER
PROGRAM
COUNTER
DUAL DPTR
ISP
PROGRAM
PORT
LOGIC