Datasheet

539

6120F–ATARM–03-Oct-06

AT91SAM7X512/256/128 Preliminary

36.8.16 CAN Message Status Register

Name: CAN_MSRx

Access Type: Read only

These register fields are updated each time a message transfer is received or aborted.

MMI is cleared by reading the CAN_MSRx register.

MRDY, MABT are cleared by writing MTCR or MACR in the CAN_MCRx register.

Warning: MRTR and MDLC state depends partly on the mailbox object type.

• MTIMESTAMP: Timer value

This field is updated only when time-triggered operations are disabled (TTM cleared in CAN_MR register). If the TEOF field

in the CAN_MR register is cleared, TIMESTAMP is the internal timer value at the start of frame of the last message

received or sent by the mailbox. If the TEOF field in the CAN_MR register is set, TIMESTAMP is the internal timer value at

the end of frame of the last message received or sent by the mailbox.

In Time Triggered Mode, MTIMESTAMP is set to 0.

• MDLC: Mailbox Data Length Code

31 30 29 28 27 26 25 24

–––––––

MMI

23 22 21 20 19 18 17 16

MRDY MABT – MRTR MDLC

15 14 13 12 11 10 9 8

MTIMESTAMP

76543210

MTIMESTAMP

Mailbox Object Type Description

Receive Length of the first mailbox message received

Receive with overwrite Length of the last mailbox message received

Transmit No action

Consumer Length of the mailbox message received

Producer Length of the mailbox message to be sent after the remote frame reception