Hitachi H8/3937 Series Hardware Manual page 189

Bits 7 and 6: Reserved bits
Bits 7 and 6 are reserved; they are always read as 1 and cannot be modified.
Bit 5: P4 /TXD pin function switch (SPC32)
2 32
This bit selects whether pin P4
Bit 5
SPC32 Description
0 Functions as P4
1 Functions as TXD
Note: Set the TE bit in SCR3 after setting this bit to 1.
*
Bit 4: P3 TXD pin function switch (SPC31)
5/ 31
This bit selects whether pin P3
Bit 4
SPC31 Description
0 Functions as P3
1 Functions as TXD
Note: * Set the TE bit in SCR3 after setting this bit to 1.
Bit 3: TXD pin output data inversion switch
32
Bit 3 specifies whether or not TXD
Bit 3
SCINV3 Description
0 TXD output data is not inverted
32
1 TXD output data is inverted
32
Bit 2: RXD pin input data inversion switch
32
Bit 2 specifies whether or not RXD
Bit 2
SCINV2 Description
0 RXD
32
1 RXD
32
/TXD is used as P4
2 32
I/O pin
2
output pin*
32
/TXD is used as P3
5 31
I/O pin
5
output pin*
31
pin output data is to be inverted.
32
pin input data is to be inverted.
32
input data is not inverted
input data is inverted
or as TXD .
2 32
or as TXD .
5 31
(initial value)
(initial value)
(initial value)
(initial value)
177