
842
PBR
Internal
data bus
RES
A18
BACK
PFC
SBYCR
INTC
IRQ4
Standby
Bus right
release
PBW
PBR: Port B read signal
PBW: Port B write signal
RES: Reset signal
PB6DR
Q
C
D
Q PB6MD0
Q PB6MD1
Q PB6IOR
Q HIZ
PB6/
IRQ4/
A18/
BACK
Figure B.17 PB6/IRQ4/A18/BACK Block Diagram