SAM7X128_14 Datasheet, PDF (501/662 Pages) ATMEL Corporation – ARM-based Flash MCU

Figure 36-15. Transmitting Messages
CAN BUS
MRDY
(CAN_MSRx)
MABT
(CAN_MSRx)
MTCR
(CAN_MCRx)
MACR
(CAN_MCRx)
Reading CAN_MSRx
Writing CAN_MDHx &
CAN_MDLx
MBx message
MBx message
Abort MBx message
Try to Abort MBx message
36.7.3.6 Remote Frame Handling
Producer/consumer model is an efficient means of handling broadcasted messages. The push model allows a producer
to broadcast messages; the pull model allows a customer to ask for messages.
Figure 36-16. Producer / Consumer Model
Producer
Request
PUSH MODEL
CAN Data Frame
Consumer
Indication(s)
Producer
Indications
PULL MODEL
CAN Remote Frame
Consumer
Request(s)
Response
CAN Data Frame
Confirmation(s)
In Pull Mode, a consumer transmits a remote frame to the producer. When the producer receives a remote frame, it
sends the answer accepted by one or many consumers. Using transmit and receive mailboxes, a consumer must
dedicate two mailboxes, one in Transmit Mode to send remote frames, and at least one in Receive Mode to capture the
producer’s answer. The same structure is applicable to a producer: one reception mailbox is required to get the remote
frame and one transmit mailbox to answer.
Mailboxes can be configured in Producer or Consumer Mode. A lonely mailbox can handle the remote frame and the
answer. With 8 mailboxes, the CAN controller can handle 8 independent producers/consumers.
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
501