MC9S08QG8 Datasheet, PDF (202/300 Pages) Freescale Semiconductor, Inc – 8-BIT HCS08 Central Processor Unit

Serial Communications Interface (S08SCIV3)
14.2.5 SCI Status Register 2 (SCIS2)
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 14-10. SCI Status Register 2 (SCIS2)
Table 14-6. SCIS2 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).
14.2.6 SCI Control Register 3 (SCIC3)
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 14-11. SCI Control Register 3 (SCIC3)
Table 14-7. SCIC3 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 SCID register. When reading 9-bit data,
read R8 before reading SCID because reading SCID completes automatic flag clearing sequences which could
allow R8 and SCID to be overwritten with new data.
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 SCID register. When writing 9-bit data, the entire
9-bit value is transferred to the SCI shift register after SCID is written so T8 should be written (if it needs to
change from its previous value) before SCID 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 SCID is written.
MC9S08QG8 and MC9S08QG4 Data Sheet, Rev. 1.01
202
Freescale Semiconductor