NEC switch - Manual (Page 65)

CHAPTER 4 PORT FUNCTIONS
User’s Manual U12978EJ3V0UD
65
Figure 4-7. Block Diagram of P23 and P24
Internal bus
WR PU0
RD
WR PORT
WR
PM
PU02
Output latch
(P23, P24)
PM23, PM24
V DD0
P-ch
P23, P24
Selector
PU0: Pull-up resistor option register 0
PM: Port mode register
RD: Port 2 read signal
WR: Port 2 write signal