
9.2.6 Serial Control Register (SCR) – H’FFDA
The SCR is an 8-bit readable/writable register that enables or disables various SCI functions. It is
initialized to H’0C at a reset and in the standby modes.
Bit 7 – Transmit Interrupt Enable (TIE):
This bit enables or disables the transmit-end interrupt
(TxI) requested when the transmit data register empty (TDRE) bit in the serial status register (SSR)
is set to “1.”
Bit 6 – Receive Interrupt Enable (RIE):
This bit enables or disables the receive-end interrupt
(RxI) requested when the receive data register full (RDRF) bit in the serial status register (SSR) is
set to “1.”
Bit 5 – Transmit Enable (TE):
This bit enables or disables the transmit function. When the
transmit function is enabled, the ATxD or CTxD pin is automatically used for output. When the
transmit function is disabled, the ATxD or CTxD pin can be used as a general-purpose I/O port.
Bit
7
6
5
4
3
—
1
—
2
—
1
—
1
0
TIE
0
R/W
RIE
0
R/W
TE
0
R/W
RE
0
R/W
CKE1
0
R/W
CKE0
0
R/W
Initial value
Read/Write
Bit 7
TIE
0
1
Description
The transmit-end interrupt request (TxI) is disabled.
The transmit-end interrupt request (TxI) is enabled.
(Initial value)
Bit 6
RIE
0
1
Description
The receive-end interrupt (RxI) request is disabled.
The receive-end interrupt (RxI) request is enabled.
(Initial value)
Bit 5
TE
0
Description
The transmit function is disabled.
The ATxD and CTxD pins can be used for general-purpose I/O.
The transmit function is enabled. When C/A = 0, the ATxD pin is used
for output. When C/A = 1, the CTxD pin is used for output.
(Initial value)
1
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