MC9S08AW16CFUE Datasheet, PDF (191/324 Pages) Freescale Semiconductor, Inc – MC9S08AW60 Features

Chapter 11 Serial Communications Interface (S08SCIV2)
11.2.5 SCI Status Register 2 (SCIxS2)
This register has one read-only status flag. Writes have no effect.
R
W
Reset
Field
2
BRK13
0
RAF
7
6
5
4
3
2
1
0
0
0
0
0
0
0
RAF
BRK13
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 11-9. SCI Status Register 2 (SCIxS2)
Table 11-6. SCIxS2 Register Field Descriptions
Description
Break Character Length — BRK13 is used to select a longer break character length. Detection of a framing
error is not affected by the state of this bit.
0 Break character is 10 bit times (11 if M = 1)
1 Break character is 13 bit times (14 if M = 1)
Receiver Active Flag — RAF is set when the SCI receiver detects the beginning of a valid start bit, and RAF is
cleared automatically when the receiver detects an idle line. This status flag can be used to check whether an
SCI character is being received before instructing the MCU to go to stop mode.
0 SCI receiver idle waiting for a start bit.
1 SCI receiver active (RxD input not idle).
11.2.6 SCI Control Register 3 (SCIxC3)
R
W
Reset
Field
7
R8
6
T8
7
6
5
4
3
2
1
0
R8
T8
TXDIR
TXINV
ORIE
NEIE
FEIE
PEIE
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 11-10. SCI Control Register 3 (SCIxC3)
Table 11-7. SCIxC3 Register Field Descriptions
Description
Ninth Data Bit for Receiver — When the SCI is configured for 9-bit data (M = 1), R8 can be thought of as a
ninth receive data bit to the left of the MSB of the buffered data in the SCIxD register. When reading 9-bit data,
both R8 and SCIxD must be read to complete the automatic RDRF clearing sequence.
Ninth Data Bit for Transmitter — When the SCI is configured for 9-bit data (M = 1), T8 may be thought of as a
ninth transmit data bit to the left of the MSB of the data in the SCIxD register. When writing 9-bit data, the entire
9-bit value is transferred to the SCI shift register after SCIxD is written so T8 should be written (if it needs to
change from its previous value) before SCIxD is written. If T8 does not need to change in the new value (such
as when it is used to generate mark or space parity), it need not be written each time SCIxD is written.
MC9S08AW60 Data Sheet, Rev 2
Freescale Semiconductor
191