DocID018909 Rev 11
RM0090
Controller area network (bxCAN)
1112
Figure 343. Example of filter numbering
Filter priority rules
Depending on the filter combination it may occur that an identifier passes successfully
through several filters. In this case the filter match value stored in the receive mailbox is
chosen according to the following priority rules:
•
A 32-bit filter takes priority over a 16-bit filter.
•
For filters of equal scale, priority is given to the
Identifier
List mode over the
Identifier
Mask mode
•
For filters of equal scale and mode, priority is given by the filter number (the lower the
number, the higher the priority).
9
8
ID List (32-
b
it)
ID Mask (32-
b
it)
ID List (16-
b
it)
ID List (32-
b
it)
Deactivated
ID Mask (16-
b
it)
ID List (32-
b
it)
Filter
0
1
3
5
6
9
ID Mask (32-
b
it)
13
FIFO0
Filter
0
1
2
3
4
5
6
7
10
11
12
1
3
ID Mask (16-
b
it)
ID List (32-
b
it)
ID Mask (16-
b
it)
ID List (16-
b
it)
Deactivated
ID Mask (16-
b
it)
ID List (32-
b
it)
Filter
2
4
7
8
10
11
ID Mask (32-
b
it)
12
FIFO1
Filter
0
1
2
4
5
6
7
8
11
12
1
3
14
3
Deactivated
9
10
Num.
Num.
Bank
Bank
ID=Identifier