Bit 4: P3
5
/TXD
31
pin function switch (SPC31)
This bit selects whether pin P3
5
/TXD
31
is used as P3
5
or as TXD
31
.
Bit 4
SPC31
Description
0
Functions as P3
5
I/O pin
(initial value)
1
Functions as TXD
31
output pin
*
Note:
*
Set the TE bit in SCR3 after setting this bit to 1.
Bit 5: P4
2
/TXD
32
pin function switch (SPC32)
This bit selects whether pin P4
2
/TXD
32
is used as P4
2
or as TXD
32
.
Bit 5
SPC32
Description
0
Functions as P4
2
I/O pin
(initial value)
1
Functions as TXD
32
output pin
*
Note:
*
Set the TE bit in SCR3 after setting this bit to 1.
Bits 7 and 6: Reserved bits
Bits 7 and 6 are reserved; they are always read as 1 and cannot be modified.
8.11.3 Note on Modification of Serial Port Control Register
When a serial port control register is modified, the data being input or output up to that point is
inverted immediately after the modification, and an invalid data change is input or output. When
modifying a serial port control register, do so in a state in which data changes are invalidated.
172