RM0402 Rev 6 935/1163
RM0402 Controller area network (bxCAN)
966
The index value of the filter number does not take into account the activation state of the
filter banks. In addition, two independent numbering schemes are used, one for each FIFO.
Refer to
Figure 327 for an example.
Figure 327. 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-bit)
ID Mask (32-bit)
ID List (16-bit)
ID List (32-bit)
Deactivated
ID Mask (16-bit)
ID List (32-bit)
Filter
0
1
3
5
6
9
ID Mask (32-bit)
13
FIFO0
Filter
0
1
2
3
4
5
6
7
10
11
12
13
ID Mask (16-bit)
ID List (32-bit)
ID Mask (16-bit)
ID List (16-bit)
Deactivated
ID Mask (16-bit)
ID List (32-bit)
Filter
2
4
7
8
10
11
ID Mask (32-bit)
12
FIFO1
Filter
0
1
2
4
5
6
7
8
11
12
13
14
3
Deactivated
9
10
Num. Num.BankBank
MS30399V2
ID=Identifier