Information

UARTx_S3 field descriptions
Field Description
7
PEF
Preamble Error Flag
Indicates that the received preamble has an error. If the received preamble length is greater than or less
than the transmit preamble length, the preamble error flag is asserted. This flag is cleared by writing 1.
0 Preamble is correct.
1 Preamble has an error.
6
WBEF
Wbase Expired Flag
Indicates that the Wbase time period has expired after beta1 time slots. This flag is cleared by writing 1.
0 WBASE time period has not expired.
1 WBASE time period has expired after beta1 time slots.
5
ISD
Initial Sync Detect
Indicates that initially, a valid one and a line code violation is detected. This flag is cleared by deasserting
EN709 bit.
0 Initial sync is not detected.
1 Initial sync is detected.
4
PRXF
Packet Received Flag
Indicates that complete packet is received. This flag is cleared by writing 1.
0 Packet is not received.
1 Packet is received.
3
PTXF
Packet Transmitted Flag
Indicates that complete packet is transmitted. This flag is cleared by writing 1. In case TX packet gets
aborted due to FIFO becoming empty or an overflow, packet transmitted flag will still be generated.
0 Packet transmission is not complete.
1 Packet transmission is complete.
2
PCTEF
Packet Cycle Timer Expired Flag
Indicates that packet cycle time period has expired with no activity on the line. This flag is cleared by
writing 1.
0 Packet cycle time has not expired.
1 Packet cycle time has expired.
1
PSF
Preamble Start Flag
Indicates start of the preamble while the packet is being transmitted. This flag is cleared by writing 1.
0 Preamble start is not detected.
1 Preamble start is detected.
0
TXFF
Transmission Fail Flag
Indicates that transmission could not proceed. This flag is asserted when the packet is queued for
transmission but before the random delay has expired and an incoming receive packet is detected. This
flag is also asserted while transmission when the TX FIFO becomes empty or overflows. In these cases,
Table continues on the next page...
Chapter 45 Universal Asynchronous Receiver/Transmitter (UART)
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
Freescale Semiconductor, Inc. 1091