Datasheet

501
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
Figure 36-15. Transmitting Messages
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
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.
MTCR
(CAN_MCRx)
MRDY
(CAN_MSRx)
CAN BUS
MBx message
Reading CAN_MSRx
Writing CAN_MDHx &
CAN_MDLx
MBx message
MACR
(CAN_MCRx)
Abort MBx message
Try to Abort MBx message
MABT
(CAN_MSRx)
CAN Data Frame
CAN Remote Frame
CAN Data Frame
Indication(s)
Request
Request(s)
Indications
Response
Confirmation(s)
PUSH MODEL
PULL MODEL
Producer
Producer
Consumer
Consumer