In this program, the software codes used are: (The work of matching this identifier is done automatically by the internal hardware of the CAN module) If a bit is incorrect, the packet will be discarded. The received identifier must match each bit of the identifier in the filter. The CAN_FilterMask register specifies that the received identifier should match the 8th bit, regardless of the other bits. The received identifier must be compared with CAN_Filter according to the bits specified in the CAN_FilterMask register.Ġx1314 binary code: 00000000 0000 0000 0001 0011 0001 0100ĬAN_Filter xxxx xxxx xxxx xxxx xxxx xxx1 xxxx xxxxĬAN_FilterMask 0000 0000 0000 0000 0000 0001 0000 0000 The filter is completely invalid, all the received identifiers passĠx1314 Binary code: 00000000 0000 0000 0001 0011 0001 0100ĬAN_Filter xxxx xxxx xxxx xxxx xxxx xxxxxxxx xxxxĬAN_FilterMask 0000 0000 0000 0000 00000000 0000 0000īecause all bits in the CAN_FilterMask mask register are 0, the corresponding identifiers are all 'don't care', that is, the ID (identifier) of the received data does not need to be performed with any bit of the CAN_Filter register match.Ģ. If the identifier I want to send is 0x1314 then the filter settings are as followsġ. Otherwise, it must be filtered by software, which consumes a certain amount of CPU resources.įirst, you need to understand the role of IdMask:įor example, the filter length is 32 bits, and the mode is the mask mode. The hardware filtering method saves CPU overhead.

To meet this demand, BeCAN provides a configurable, variable bit width 6 (0-5) filter group for the application, which is used to receive only those messages required by the software.

When a node receives a message, it determines whether the software needs the message according to the value of the identifier if necessary, it is copied into RAM if it is not needed, the message is discarded without software intervention. Therefore, the sender sends the message to all receivers in the form of broadcast. In the CAN protocol, the identifier of the message does not represent the address of the node, but is related to the content of the message.

Can bus programming software