Electronics America Single-Chip Microcontrollers User's Manual

CHAPTER 4 PORT FUNCTIONS
User’s Manual U15331EJ4V1UD 81
Figure 4-6. Block Diagram of P22 and P25
P22/SI20/
RxD20,
P25/SI10
WR
PUB2
RD
WR
PORT
WR PM
PUB22, PUB25
Alternate
function
Output latch
(P22, P25)
PM22, PM25
V DD
P-ch
Internal bus
Selector
PUB2: Pull-up resistor option register B2
PM: Port mode register
RD: Port 2 read signal
WR: Port 2 write signal