TC1796
Peripheral Units (Vol. 2 of 2)
Controller Area Network (MultiCAN) Controller
User’s Manual 22-110 V2.0, 2007-07
MultiCAN, V2.0
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
Time-Triggered CAN (TTCAN): The Message
Object Mask Register specifies the position(s)
within the transmission matrix at which the
message object n may be transmitted. 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) that
matches the actual position within the
transmission matrix somewhere before this
object in the list.
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
identifier + IDE + DIR (with respect to CAN
arbitration rules) somewhere in the list (see
Table 22-12).
11
B
Transmit acceptance filtering is based on the
list order (as PRI = 01
B
).
Field Bits Type Description
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