PXS20RM Datasheet, PDF (984/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

LIN Controller (LINFlexD)
• Select the desired mode (Master, Slave or UART)
• Set up the baud rate register
• If LIN Slave mode with filter activation is selected, initialize the identifier list
31.6.2 Normal mode
After initialization is complete, the software must clear LINCR1[INIT] to put the LINFlexD controller into
Normal mode.
31.6.3 Sleep (low-power) mode
To reduce power consumption, LINFlexD has a low-power mode called Sleep mode. In this mode, the
LINFlexD clock is stopped. Consequently, the LINFlexD will not update the status bits, but software can
still access the LINFlexD registers.
To enter this mode, the software must set LINCR1[SLEEP].
LINFlexD can be awakened (exit Sleep mode) in one of two ways:
• The software clears LINCR1[SLEEP]
• Automatic wake-up is enabled (LINCR1[AWUM] is set) and LINFlexD detects LIN bus activity
(that is, if a wakeup pulse of 150 s is detected on the LIN bus)
On LIN bus activity detection, hardware automatically performs the wake-up sequence by clearing
LINCR1[SLEEP] if LINCR1[AWUM] is set. To exit from Sleep mode if LINCR1[AWUM] is cleared, the
software must clear LINCR1[SLEEP] when a wake-up event occurs.
31.7 LIN modes
31.7.1 Master mode
In Master mode, the software uses the message buffer to handle the LIN messages.
Master mode is selected when LINCR1[MME] is set.
31.7.1.1 LIN header transmission
According to the LIN protocol, any communication on the LIN bus is triggered by the master sending a
header. The header is transmitted by the master task while the data is transmitted by the slave task of a
node.
To transmit a header with LINFlexD the application must set up the identifier, the data field length and
configure the message (direction and checksum type) in the BIDR register before requesting the header
transmission by setting LINCR2[HTRQ].
31-8
PXS20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor