CHAPTER 4 PORT FUNCTIONS
User’s Manual U18172EJ2V0UD
58
Figure 4-7. Block Diagram of P40 and P43
P40, P43
WR
PU
RD
WR
PORT
WR
PM
PU40, PU43
PM40, PM43
V
DD
P-ch
PU4
PM4
Internal bus
Output latch
(
P40, P43
)
Selector
P4
P4:
Port register 4
PU4:
Pull-up resistor option register 4
PM4:
Port mode register 4
RD:
Read signal
WR
××
: Write signal
4.3 Registers Controlling Port Functions
The ports are controlled by the following four types of registers.
•
Port mode registers (PM2 to PM4)
•
Port registers (P2 to P4)
•
Port mode control register 2 (PMC2)
•
Pull-up resistor option registers (PU2 to PU4)