NEC switch - Manual (Page 66)

CHAPTER 4 PORT FUNCTIONS
User’s Manual U12978EJ3V0UD
66
Figure 4-8. Block Diagram of P25
RD
V DD0
P25
WR POM1
WR
PU0
WR PORT
WR
PM
Output latch
(P25)
PM25
PU02
P-ch
P-ch
N-ch
V DD0
POM125
Internal bus
Selector
POM1: Port output mode register 1
PU0: Pull-up resistor option register 0
PM: Port mode register
RD: Port 2 read signal
WR: Port 2 write signal