Atmel Xplained Pro Evaluation Kit ATSAM4E-XPRO ATSAM4E-XPRO Data Sheet

SAM4E [DATASHEET]

Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14

676

case, the consumer mailbox must have a lower number than the Receive with Overwrite mailbox. The transfer
command can be triggered for all mailboxes at the same time by setting several MBx fields in the CAN_TCR. 

Using the free running 16-bit internal timer, the CAN controller can be set in one of the two following timing modes:



Timestamping Mode: The value of the internal timer is captured at each Start Of Frame or each End Of 
Frame.



Time Triggered Mode: The mailbox transfer operation is triggered when the internal timer reaches the 
mailbox trigger.

Timestamping Mode is enabled by clearing the TTM bit in the CAN_MR. Time Triggered Mode is enabled by
setting the TTM bit in the CAN_MR.

Each mailbox has its own timestamp value. Each time a message is sent or received by a mailbox, the 16-bit value
MTIMESTAMP of the CAN_TIMESTP register is transferred to the LSB bits of the CAN_MSRx. The value read in
the CAN_MSRx corresponds to the internal timer value at the Start Of Frame or the End Of Frame of the message
handled by the mailbox. 

MTCR

(CAN_MCRx)

MRDY

(CAN_MSRx)

CAN BUS

Remote Frame

Message x

Message y

Message y

(CAN_MDLx

CAN_MDHx)

MMI

(CAN_MSRx)

Remote Frame

Message x

TEOF 

(CAN_MR)

MTIMESTAMP

(CAN_MSRx)

CAN_TIM

CAN BUS

MTIMESTAMP

(CAN_MSRy)

Message 1

Message 2

Start of Frame

TIMESTAMP

(CAN_TSTP)

End of Frame

Timestamp 1

Timestamp 1

Timestamp 2

Timestamp 2