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UARTx_C2 field descriptions (continued)
Field
Description
0
IDLE interrupt requests disabled.
1
IDLE interrupt requests enabled.
3
TE
Transmitter Enable
Enables the UART transmitter. TE can be used to queue an idle preamble by clearing and then setting TE.
When C7816[ISO_7816E] is set/enabled and C7816[TTYPE] = 1, this field is automatically cleared after
the requested block has been transmitted. This condition is detected when TL7816[TLEN] = 0 and four
additional characters are transmitted.
0
Transmitter off.
1
Transmitter on.
2
RE
Receiver Enable
Enables the UART receiver.
0
Receiver off.
1
Receiver on.
1
RWU
Receiver Wakeup Control
This field can be set to place the UART receiver in a standby state. RWU automatically clears when an
RWU event occurs, that is, an IDLE event when C1[WAKE] is clear or an address match when C1[WAKE]
is set. This field must be cleared when C7816[ISO_7816E] is set.
NOTE: RWU must be set only with C1[WAKE] = 0 (wakeup on idle) if the channel is currently not idle.
This can be determined by S2[RAF]. If the flag is set to wake up an IDLE event and the channel
is already idle, it is possible that the UART will discard data. This is because the data must be
received after an IDLE is detected before IDLE is allowed to reasserted.
0
Normal operation.
1
RWU enables the wakeup function and inhibits further receiver interrupt requests. Normally, hardware
wakes the receiver by automatically clearing RWU.
0
SBK
Send Break
Toggling SBK sends one break character from the following: See
for the
number of logic 0s for the different configurations. Toggling implies clearing the SBK field before the break
character has finished transmitting. As long as SBK is set, the transmitter continues to send complete
break characters (10, 11, or 12 bits, or 13 or 14 bits). Ensure that C2[TE] is asserted atleast 1 clock before
assertion of this bit.
• 10, 11, or 12 logic 0s if S2[BRK13] is cleared
• 13 or 14 logic 0s if S2[BRK13] is set.
This field must be cleared when C7816[ISO_7816E] is set.
0
Normal transmitter operation.
1
Queue break characters to be sent.
Memory map and registers
KL27 Sub-Family Reference Manual , Rev. 5, 01/2016
686
Freescale Semiconductor, Inc.