CHAPTER 12 PORT FUNCTIONS
568
User’s Manual U15195EJ5V0UD
12.3.4 Port 3
Port 3 is a 5-bit I/O port in which input or output can be specified in 1-bit units
7
−
P3
6
−
5
−
4
P34
3
P33
2
P32
1
P31
0
P30
Address
FFFFF406H
After reset
Undefined
Bit position
Bit name
Function
4 to 0
P3n
(n = 4 to 0)
I/O port
Besides functioning as a port, in control mode, it also can operate as the serial interface (UART0, UART1/CSI1)
I/O.
(1) Operation in control mode
Port
Alternate Pin Name
Remarks
Block Type
P30 RXD0
C
P31 TXD0
A
P32 RXD1/SI1
G
P33 TXD1/SO1
F
Port 3
P34 ASCK1/SCK1
Serial interface (UART0, UART1/CSI1) I/O
H
Caution P30, P32, and P34 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 3 mode register (PM3) is used to set the I/O mode of port 3 and the port 3 mode control register
(PMC3) and the port 3 function control register (PFC3) are used to set the operation in control mode.
(a) Port 3 mode register (PM3)
This register can be read or written in 8-bit or 1-bit units.
7
1
PM3
6
1
5
1
4
PM34
3
PM33
2
PM32
1
PM31
0
PM30
Address
FFFFF426H
After reset
FFH
Bit position
Bit name
Function
4 to 0
PM3n
(n = 4 to 0)
Specifies input/output mode of P3n pin.
0: Output mode (output buffer on)
1: Input mode (output buffer off)
Содержание PD703114
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