16 can message status register – Rainbow Electronics AT91CAP9S250A User Manual
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731
6264A–CAP–21-May-07
AT91CAP9S500A/AT91CAP9S250A
39.8.16
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
15
MTIMESTAMP
14
MTIMESTAMP
13
MTIMESTAMP
12
MTIMESTAMP
11
MTIMESTAMP
10
MTIMESTAMP
9
MTIMESTAMP
8
7
6
5
4
3
2
1
0
MTIMESTAMP
7
MTIMESTAMP
6
MTIMESTAMP
5
MTIMESTAMP
4
MTIMESTAMP
3
MTIMESTAMP
2
MTIMESTAMP
1
MTIMESTAMP
0
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