NEC switch - Manual (Page 64)

CHAPTER 4 PORT FUNCTIONS
User’s Manual U12978EJ3V0UD
64
Figure 4-6. Block Diagram of P22
PU0: Pull-up resistor option register 0
PM: Port mode register
RD: Port 2 read signal
WR: Port 2 write signal
Internal bus
V DD0
P-ch
P22/SI10
WR PU0
RD
WR PORT
WR
PM
PU02
Alternate
function
Output latch
(P22)
PM22
Selector