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also outlines additional details regarding the RXEDGIF
interrupt because of its complexity of operation. Any of the UART interrupt requests
listed in the table can be used to bring the CPU out of Wait mode.
Table 38-14. UART interrupt sources
Interrupt Source
Flag
Local enable
DMA select
Transmitter
TDRE
TIE
TDMAS = 0
Transmitter
TC
TCIE
-
Receiver
IDLE
ILIE
-
Receiver
RDRF
RIE
RDMAS = 0
Receiver
RXEDGIF
RXEDGIE
-
Receiver
OR
ORIE
-
Receiver
NF
NEIE
-
Receiver
FE
FEIE
-
Receiver
PF
PEIE
-
Receiver
WT
WTWE
-
Receiver
CWT
CWTE
-
Receiver
BWT
BWTE
-
Receiver
INITD
INITDE
-
Receiver
TXT
TXTE
-
Receiver
RXT
RXTE
-
Receiver
GTV
GTVE
-
38.7.1 RXEDGIF description
S2[RXEDGIF] is set when an active edge is detected on the RxD pin. Therefore, the
active edge can be detected only when in two wire mode. A RXEDGIF interrupt is
generated only when S2[RXEDGIF] is set. If RXEDGIE is not enabled before
S2[RXEDGIF] is set, an interrupt is not generated.
38.7.1.1 RxD edge detect sensitivity
Edge sensitivity can be software programmed to be either falling or rising. The polarity
of the edge sensitivity is selected using S2[RXINV]. To detect the falling edge,
S2[RXINV] is programmed to 0. To detect the rising edge, S2[RXINV] is programmed
to 1.
Synchronizing logic is used prior to detect edges. Prior to detecting an edge, the receive
data on RxD input must be at the deasserted logic level. A falling edge is detected when
the RxD input signal is seen as a logic 1 (the deasserted level) during one module clock
System level interrupt sources
KL27 Sub-Family Reference Manual , Rev. 5, 01/2016
736
Freescale Semiconductor, Inc.