Message Reception - NEC Renesas V850/SC1 User Manual

19.8.2 Message reception

When two or more message buffers of the CAN module receive a message, the storage priority of the received
messages is as follows (the storage priority differs between data frames and remote frames).
Priority
2 (High) Unmasked message buffer
3 Message buffer linked to mask 0
4 Message buffer linked to mask 1
5 Message buffer linked to mask 2
6 (Low) Message buffer linked to mask 3
Priority
1 (High) Transmit message buffer
2 Unmasked message buffer
3 Message buffer linked to mask 0
4 Message buffer linked to mask 1
5 Message buffer linked to mask 2
6 (Low) Message buffer linked to mask 3
A message (data frame or remote frame) is always stored in a receive message buffer with a higher priority, not in
a receive buffer with a lower priority. For example, when the unmasked receive message buffer and the message
buffer linked to the mask 0 have the same ID, a message is always stored in the unmasked receive message buffer
even if the unmasked receive message buffer has already received a message.
When two or more message buffers with the same priority exist in the same CAN module, the priority is as follows.
Priority
1 (High) DN bit of M_STAT register is not set (1)
2 (Low) DN bit of M_STAT register is set (1)
When two or more message buffers with the same priority exist, the message buffer with the smaller message
number takes precedence.
Also, when two or more message buffers with the same ID exist, the message buffer with the smaller message
number takes precedence.
CHAPTER 19 FCAN CONTROLLER (V850/SC3)
Table 19-13. Storage Priority for Data Frame Reception
Table 19-14. Storage Priority for Remote Frame Reception
Table 19-15. Priority of Same Priority Level
User's Manual U15109EJ3V0UD
Conditions
Conditions
Condition
635