HD6473258CP10 Datasheet, PDF (183/301 Pages) Renesas Technology Corp – Hitachi Single-Chip Microcomputer

Bit 4 – Receive Enable (RE): This bit enables or disables the receive function. When the receive
function is enabled, the RxD pin is automatically used for input. When the receive function is
disabled, the RxD pin is available as a general-purpose I/O port.
Bit 4
RE Description
0 The receive function is disabled. The RxD pin can be
used for general-purpose I/O.
1 The receive function is enabled.
The RxD pin is used for input.
(Initial value)
Bits 3 and 2 – Reserved: These bits cannot be modified and are always read as 1.
Bit 1 – Clock Enable 1 (CKE1): This bit selects the internal or external clock source for the baud
rate generator. When the external clock source is selected, the SCK pin is automatically used for
input of the external clock signal.
Bit 1
CKE1
0
1
Description
Internal clock source.
When C/A = 1, the clock is output at SCK.
When C/A = 0, clock output depends on CKE0.
External clock source, input at SCK.
(Initial value)
Bit 0 – Clock Enable 0 (CKE0): When an internal clock source is used in asynchronous mode,
this bit enables or disables serial clock output at the SCK pin.
This bit is ignored when the external clock is selected, or when the synchronous mode is selected.
Bit 0
CKE0
0
1
Description
The SCK pin is not used by the SCI (and is available as
a general-purpose I/O port).
The SCK pin is used for serial clock output.
(Initial value)
For further information on clock source selection, see table 9-6 in Section 9.3, Operation.
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