import ctypes as ct
[docs]class MessageInfo(ct.Structure):
"""Provides more information about the LIN message.
The precision of the timing data given in us (microseconds) can be less
than one microsecond; for low bitrates the lowest bits might always be
zero.
The min and max values listed inside [] of the message timing values can be
calculated from the LIN specification by using the shortest (0 bytes) or
longest (8 bytes) messages at the lowest or highest allowed bitrate.
.. note:: The LIN interface will accept messages that are a bit
out-of-bounds as well.
.. py:attribute:: timestamp
Kvaser DRV Lin timestamp - Timestamp in milliseconds of the falling
edge of the synch break of the message. Uses the canlib CAN timer.
Kvaser LIN Leaf timestamp - Timestamp in milliseconds of the falling
edge of the synch break of the message. Uses the canlib CAN timer.
.. note:: All Kvaser Leaf with Kvaser MagiSync&tm; are synchronized
(also with CAN channels).
.. py:attribute:: bitrate
The bitrate of the message in bits per seconds. Range [1000 .. 20000]
(plus some margin)
.. py:attribute:: byteTime
Start time in microseconds of each data byte. In case of 8-byte
messages, the crc time isn't included (but can be deduced from
frameLength).
.. note:: Not supported by all devices.
.. py:attribute:: checkSum
The checksum as read from the LIN bus. Might not match the data in case
of `MessageFlag.CSUM_ERROR`.
.. py:attribute:: frameLength
The total frame length in microseconds; from the synch break to the end
of the crc. [2200 .. 173600]
.. py:attribute:: idPar
The id with parity of the message as read from the LIN bus. Might be
invalid in case of `MessageFlag.PARITY_ERROR`.
.. py:attribute:: synchBreakLength
Length of the synch break in microseconds. [650 .. 13000], [400
.. 8000] for a wakeup signal.
.. py:attribute:: synchEdgeTime
Time in microseconds of the falling edges in the synch byte relative
the falling edge of the start bit.
.. note:: Not supported by all devices.
"""
_fields_ = [
("timestamp", ct.c_ulong),
("synchBreakLength", ct.c_ulong),
("frameLength", ct.c_ulong),
("bitrate", ct.c_ulong),
("checkSum", ct.c_ubyte),
("idPar", ct.c_ubyte),
("z", ct.c_ushort), #: Dummy for alignment
("synchEdgeTime", ct.c_ulong * 4),
("byteTime", ct.c_ulong * 8),
]