Service manual

74
DV-NC55U/C/M
Port 2 Port 4
Port 09
Port 3Port 1
HIGH FREQ
OSC
LOW FREQ
OSC
P22~P20 P47~P40
P17~P10 P37~P30 P07~P00
STOP
INTREQ
TI0, TI1
RXD,
TXD
UART8bit TMR
SCK,
SI, SO
ch. 0 ch. 1
ch. 1 ch. 0
INTERRUPT
CONTROLLER
STANDBY
CONTROLLER
fsfc
CLK GEAR, TBT
OSC
SYSCLK
CPU WDT
ETC0
SERIAL
INTERFACE
EA
EXTERNAL BUS
CONTROLLER
TO0
TO1
RD, WR, ALE, WAIT, CLK
AD0~7
A8~A15
16-bit
Expansion Timer
DVO
ROM
16KB
RAM
512B
RESET
XIN
XOUT
• Block Diagram