XC886/888CLM
Controller Area Network (MultiCAN) Controller
User’s Manual
15-93
V1.3, 2010-02
MultiCAN, V1.0
PRI
[31:30] rw
Priority Class
PRI assigns one of the four priority classes 0, 1, 2, 3
to message object n. A lower PRI number defines a
higher priority. Message objects with lower PRI value
always win acceptance filtering for frame reception
and transmission over message objects with higher
PRI value. Acceptance filtering based on
identifier/mask and list position is performed only
between message objects of the same priority class.
PRI also determines the acceptance filtering method
for transmission:
00
B
Reserved.
01
B
Transmit acceptance filtering is based on the
list order. This means that message object n is
considered for transmission only if there is no
other message object with valid transmit
request (MSGVAL & TXEN0 & TXEN1 = 1)
somewhere before this object in the list.
10
B
Transmit acceptance filtering is based on the
CAN identifier. This means, message object n
is considered for transmission only if there is no
other message object with higher priority
iden IDE + DIR (with respect to CAN
arbitration rules) somewhere in the list (see
11
B
Transmit acceptance filtering is based on the
list order (as PRI = 01
B
).
Field
Bits
Type Description
*