During receiver address matching, the address matching is performed in hardware and the
LPUART receiver will ignore all characters that do not meet the address match
requirements.
Table 47-17. Receiver Wakeup Options
RWU
MA1 | MA2
MATCFG
WAKE:RWUID
Receiver Wakeup
0
0
X
X
Normal operation
1
0
00
00
Receiver wakeup on
idle line, IDLE flag not
set
1
0
00
01
Receiver wakeup on
idle line, IDLE flag set
1
0
00
10
Receiver wakeup on
address mark
1
1
11
X0
Receiver wakeup on
data match
0
1
00
X0
Address mark address
match, IDLE flag not set
for discarded
characters
0
1
00
X1
Address mark address
match, IDLE flag set for
discarded characters
0
1
01
X0
Idle line address match
0
1
10
X0
Address match on and
address match off,
IDLE flag not set for
discarded characters
0
1
10
X1
Address match on and
address match off,
IDLE flag set for
discarded characters
47.3.3.2.1 Idle-line wakeup
When wake is cleared, the receiver is configured for idle-line wakeup. In this mode,
LPUART_CTRL[RWU] is cleared automatically when the receiver detects a full
character time of the idle-line level. The LPUART_CTRL[M] and
LPUART_BAUD[M10] control bit selects 8-bit to 10-bit data mode and the
LPUART_BAUD[SBNS] bit selects 1-bit or 2-bit stop bit number that determines how
many bit times of idle are needed to constitute a full character time, 10 to 13 bit times
because of the start and stop bits.
When LPUART_CTRL[RWU] is one and LPUART_STAT[RWUID] is zero, the idle
condition that wakes up the receiver does not set the LPUART_STAT[IDLE] flag. The
receiver wakes up and waits for the first data character of the next message that sets the
Functional description
K22F Sub-Family Reference Manual , Rev. 3, 7/2014
1242
Freescale Semiconductor, Inc.
