CHAPTER 4 PORT FUNCTIONS
User’s Manual U18172EJ2V0UD
56
4.2.2 Port
3
The P32 pin is a 1-bit I/O port with an output latch. This pin can be set to the input or output mode by using port
mode register 3 (PM3). When this pin is used as an input port, an on-chip pull-up resistor can be connected in 1-bit
units by using pull-up resistor option register 3 (PU3). This pin can also be used for external interrupt request input.
The P32 pin is a Reset signal generation sets port 3 to the input mode.
The P34 pin is a 1-bit input-only port. This pin is also used as a RESET pin, and when the power is turned on, this
is the reset function. For the setting method for pin functions, see
CHAPTER 15 OPTION BYTE
.
When P34 is used as an input port pin, connect the pull-up resistor.
Figures 4-5 and 4-6 show the block diagrams of port 3.
Figure 4-5. Block Diagram of P32
P32/INTP1
WR
PU
RD
WR
PORT
WR
PM
PU32
PM32
V
DD
P-ch
PU3
PM3
Alternate
function
Selector
Output latch
(P32)
Internal bus
P3
P3:
Port register 3
PU3:
Pull-up resistor option register 3
PM3:
Port mode register 3
RD:
Read signal
WR
××
: Write signal