Information

UARTx_S2 field descriptions (continued)
Field Description
0 LSB (bit0) is the first bit that is transmitted following the start bit. Further, the first bit received after the
start bit is identified as bit0.
1 MSB (bit8, bit7 or bit6) is the first bit that is transmitted following the start bit depending on the setting
of C1[M] and C1[PE]. Further, the first bit received after the start bit is identified as bit8, bit7 or bit6
depending on the setting of C1[M] and C1[PE].
4
RXINV
Receive Data Inversion
Setting this bit, reverses the polarity of the received data input. In NRZ format, a one is represented by a
mark and a zero is represented by a space for normal polarity, and the opposite for inverted polarity. In
IrDA format, a zero is represented by short high pulse in the middle of a bit time remaining idle low for a
one for normal polarity, and a zero is represented by short low pulse in the middle of a bit time remaining
idle high for a one for inverted polarity.This bit is automatically set or cleared when C7816[INIT] and
C7816[ISO7816E] are enabled and an initial character is detected.
NOTE: Setting RXINV inverts the RxD input for: data bits, start and stop bits, break, and idle. When
C7816[ISO7816E] is set/enabled then only the data bits and the parity bit are inverted.
0 Receive data is not inverted.
1 Receive data is inverted.
3
RWUID
Receive Wakeup Idle Detect
When RWU is set and WAKE is cleared, this bit controls whether the idle character that wakes the
receiver sets the S1[IDLE] bit.This bit must be cleared when C7816[ISO7816E] is set/enabled.
0 The S1[IDLE] bit is not set upon detection of an idle character.
1 The S1[IDLE] bit is set upon detection of an idle character.
2
BRK13
Break Transmit Character Length
This bit determines whether the transmit break character is 10, 11, or 12 bits long, or 13 or 14 bits long.
Refer to Transmitting break characters for the length of the break character for the different
configurations. The detection of a framing error is not affected by this bit.
0 Break character is 10, 11, or 12 bits long.
1 Break character is 13 or 14 bits long.
1
LBKDE
LIN Break Detection Enable
LBKDE selects a longer break character detection length. While LBKDE is set, the S1[RDRF], S1[NF],
S1[FE], and S1[PF] flags are prevented from setting. When LBKDE is set, see Overrun operation. The
LBKDE bit must be cleared when C7816[ISO7816E] is set.
0 Break character is detected at length of 10 bit times (C1[M] = 0), 11 (C1[M] = 1 and C4[M10] = 0), or
12 (C1[M] = 1, C4[M10] = 1, and S1[PE] = 1).
1 Break character is detected at length of 11 bits times (if C1[M] = 0 or 12 bits time (if C1[M] = 1).
0
RAF
Receiver Active Flag
RAF is set when the UART receiver detects a logic 0 during the RT1 time period of the start bit search.
RAF is cleared when the receiver detects an idle character when C7816[ISO7816E] is cleared/disabled.
When C7816[ISO7816E] is enabled the RAF is cleared if the C7816[TTYPE] = 0 expires or the
C7816[TTYPE] = 1 expires.
NOTE: In the case when C7816[ISO7816E] is set and C7816[TTYPE] = 0, it is possible to configure the
guard time to be 12. However, in the event that a NACK is required to be transmitted the data
Table continues on the next page...
Chapter 45 Universal Asynchronous Receiver/Transmitter (UART)
K10 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc. 1271