Functional Description and Application Information
Serial Communication Interface (S08SCIV4)
MM912F634
Freescale Semiconductor
117
When using an internal oscillator in a LIN system, it is necessary to raise the break detection threshold by one bit time. Under
the worst case timing conditions allowed in LIN, it is possible that a 0x00 data character can appear to be 10.26 bit times long at
a slave which is running 14% faster than the master. This would trigger normal break detection circuitry which is designed to
detect a 10 bit break symbol. When the LBKDE bit is set, framing errors are inhibited and the break detection threshold changes
from 10 bits to 11 bits, preventing false detection of a 0x00 data character as a LIN break symbol.
4.15.2.6
SCI Control Register 3 (SCIC3)
Table 136. SCI Control Register 3 (SCIC3)
Access: User read/write
76
543
210
RR8
T8
TXDIR
TXINV(94)
ORIE
NEIE
FEIE
PEIE
W
Reset
0
000
00
Note:
106. Offset related to 0x0200 for blocking access and 0x300 for non blocking access within the global address space.
Table 137. SCIC3 Field Descriptions
Field
Description
7
R8
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.
6
T8
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.
5
TXDIR
TxD Pin Direction in Single-wire Mode — When the SCI is configured for single-wire half-duplex operation
(LOOPS = RSRC = 1), this bit determines the direction of data at the TxD pin.
0 TxD pin is an input in single-wire mode.
1 TxD pin is an output in single-wire mode.
4
Transmit Data Inversion — Setting this bit reverses the polarity of the transmitted data output.
0 Transmit data not inverted
1 Transmit data inverted
3
ORIE
Overrun Interrupt Enable — This bit enables the overrun flag (OR) to generate hardware interrupt requests.
0 OR interrupts disabled (use polling).
1 Hardware interrupt requested when OR = 1.
2
NEIE
Noise Error Interrupt Enable — This bit enables the noise flag (NF) to generate hardware interrupt requests.
0 NF interrupts disabled (use polling).
1 Hardware interrupt requested when NF = 1.
1
FEIE
Framing Error Interrupt Enable — This bit enables the framing error flag (FE) to generate hardware interrupt requests.
0 FE interrupts disabled (use polling).
1 Hardware interrupt requested when FE = 1.
0
PEIE
Parity Error Interrupt Enable — This bit enables the parity error flag (PF) to generate hardware interrupt requests.
0 PF interrupts disabled (use polling).
1 Hardware interrupt requested when PF = 1.
Note:
107. Setting TXINV inverts the TxD output for all cases: data bits, start and stop bits, break, and idle.