CHAPTER 12 PORT FUNCTIONS
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User’s Manual U15195EJ5V0UD
12.3.2 Port 1
Port 1 is a 3-bit I/O port in which input or output can be specified in 1-bit units.
7
−
P1
6
−
5
−
4
−
3
−
2
P12
1
P11
0
P10
Address
FFFFF402H
After reset
Undefined
Bit position
Bit name
Function
2 to 0
P1n
(n = 2 to 0)
I/O port
Besides functioning as a port, in control mode, it can also operate as the timer/counter I/O and external interrupt
request input.
(1) Operation in control mode
Port
Alternate Pin Name
Remarks
Block Type
P10 TIUD10/TO10
Timer/counter
I/O
K
P11 TCUD10/INTP100
Port 1
P12 TCLR10/INTP101
Timer/counter input or external interrupt request input
B
Caution P10 to P12 have hysteresis characteristics when the alternate functions are input, but not in the
port mode.
(2) Setting of I/O mode and control mode
The port 1 mode register (PM1) is used to set the I/O mode of port 1 and the port 1 mode control register
(PMC1) and port function control register 1 (PFC1) are used to set the operation in control mode.
(a) Port 1 mode register (PM1)
This register can be read or written in 8-bit or 1-bit units. Write 1 in bits 3 to 7.
7
1
PM1
6
1
5
1
4
1
3
1
2
PM12
1
PM11
0
PM10
Address
FFFFF422H
After reset
FFH
Bit position
Bit name
Function
2 to 0
PM1n
(n = 2 to 0)
Specifies input/output mode of P1n pin.
0: Output mode (output buffer on)
1: Input mode (output buffer off)