Datasheet

CHAPTER 4 PORT FUNCTIONS
User’s Manual U18172EJ3V0UD
64
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 in
μ PD78F920x is used as an input port pin, connect the pull-up resistor.
When P34 in μ PD78F950x is used as an input port pin, an on-chip pull-up resistor can be connected in 1-bit units
by using pull-up resistor option register 3 (PU3).
Figures 4-8 and 4-10 show the block diagrams of port 3.
Figure 4-8. 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
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