RM0008 Controller area network (bxCAN)
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Refer to Figure 199.
Furthermore, the filters can be configured in mask mode or in identifier list mode.
Mask mode
In mask mode the identifier registers are associated with mask registers specifying which
bits of the identifier are handled as “must match” or as “don’t care”.
Identifier list mode
In identifier list mode, the mask registers are used as identifier registers. Thus instead of
defining an identifier and a mask, two identifiers are specified, doubling the number of single
identifiers. All bits of the incoming identifier must match the bits specified in the filter
registers.
Filter bank scale and mode configuration
The filter banks are configured by means of the corresponding CFMR register. To configure
a filter bank it must be deactivated by clearing the FACT bit in the CAN_FAR register. The
filter scale is configured by means of the corresponding FSCx bit in the CFSCR register,
refer to Figure 199. The identifier list or identifier mask mode for the corresponding
Mask/Identifier registers is configured by means of the FBMx bits in the CFMR register.
To filter a group of identifiers, configure the Mask/Identifier registers in mask mode.
To select single identifiers, configure the Mask/Identifier registers in identifier list mode.
Filters not used by the application should be left deactivated.
Each filter within a filter bank is numbered (called the Filter Number) from 0 to a maximum
dependent on the mode and the scale of each of the 14 filter banks.
Concerning the filter configuration, refer to Figure 199.
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