UPD78F0838 Renesas Electronics Corporation., UPD78F0838 Datasheet - Page 606

• Manufacturer Part Number: UPD78F0838
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

15.9 Message Reception
15.9.1 Message reception
received message. All message buffers satisfying the following conditions are included in that evaluation (RX-search
process).
the priority explained below. The message is always stored in the message buffer with the highest priority, not in a
message buffer with a low priority. For example, when an unmasked receive message buffer and a receive message
buffer linked to mask 1 have the same ID, the received message is not stored in the message buffer linked to mask 1,
even if that message buffer has not received a message and a message has already been received in the unmasked
receive message buffer. In other words, when a condition has been set to store a message in two or more message
buffers with different priorities, the message buffer with the highest priority always stores the message; the message
is not stored in message buffers with a lower priority. This also applies when the message buffer with the highest
priority is unable to receive and store a message (i.e., when DN = 1 indicating that a message has already been
received, but rewriting is disabled because OWS = 0). In this case, the message is not actually received and stored in
the candidate message buffer with the highest priority, but neither is it stored in a message buffer with a lower priority.
604
Remark m = 0 to 15
1 (high)
2
3
4
5(low)
In all the operation modes, the complete message buffer area is analyzed to find a suitable buffer to store a newly
- Used as a message buffer
- Set as a receive message buffer
- Ready for reception
When two or more message buffers of the CAN module receive a message, the message is stored according to
(MT [2:0] bits of C0MCONFm register set to 001B, 010B, 011B, 100B, or 101B.)
(RDY bit of C0MCTRLm register set to 1.)
(MA0 bit of C0MCONFm register set to 1B.)
Priority
Unmasked message buffer
Message buffer linked to mask 1
Message buffer linked to mask 2
Message buffer linked to mask 3
Message buffer linked to mask 4
Preliminary User’s Manual U19748EJ1V0UD
CHAPTER 15 CAN CONTROLLER
Storing Condition If Same ID is Set
DN = 0
DN = 1 and OWS = 1
DN = 0
DN = 1 and OWS = 1
DN = 0
DN = 1 and OWS = 1
DN = 0
DN = 1 and OWS = 1
DN = 0
DN = 1 and OWS = 1