Note On Modification Of Serial Port Control Register; Application Note; The Management Of The Un-Use Terminal - Hitachi H8/3937 Series Hardware Manual

Bit 1: TXD pin output data inversion switch
31
Bit 1 specifies whether or not TXD
Bit 1
SCINV1 Description
0 TXD output data is not inverted
31
1 TXD output data is inverted
31
Bit 0: RXD pin input data inversion switch
31
Bit 0 specifies whether or not RXD
Bit 0
SCINV0 Description
0 RXD
31
1 RXD
31
8.13.3

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
8.14

Application Note

8.14.1

The Management of the Un-Use Terminal

If an I/O pin not used by the user system is floating, pull it up or down.
• If an unused pin is an input pin, handle it in one of the following ways:
 Pull it up to V
CC
 Pull it up to V
CC
 Pull it down to V
• If an unused pin is an output pin, handle it in one of the following ways:
 Set the output of the unused pin to high and pull it up to V
 Set the output of the unused pin to high and pull it up to V
approximately 100 kΩ.
 Set the output of the unused pin to low and pull it down to V
approximately 100 kΩ.
178
pin output data is to be inverted.
31
pin input data is to be inverted.
31
input data is not inverted
input data is inverted
with an on-chip pull-up MOS.
with an external resister of approximately 100 kΩ.
with an external resister of approximately 100 kΩ.
SS
(initial value)
(initial value)
with an on-chip pull-up MOS.
CC
with an external resister of
CC
with an external resister of
SS