LM3S2911 Datasheet, PDF (529/642 Pages) Texas Instruments – Stellaris® LM3S2911 Microcontroller

Stellaris^® LM3S2911 Microcontroller
Register 2: CAN Status (CANSTS), offset 0x004
Important: This register is read-sensitive. See the register description for details.
The status register contains information for interrupt servicing such as Bus-Off, error count threshold,
and error types.
The LEC field holds the code that indicates the type of the last error to occur on the CAN bus. This
field is cleared when a message has been transferred (reception or transmission) without error. The
unused error code 7 may be written by the CPU to manually set this field to an invalid error so that
it can be checked for a change later.
An error interrupt is generated by the BOFF and EWARN bits and a status interrupt is generated by
the RXOK, TXOK, and LEC bits, if the corresponding enable bits in the CAN Control (CANCTL)
register are set. A change of the EPASS bit or a write to the RXOK, TXOK, or LEC bits does not
generate an interrupt.
Reading the CAN Status (CANSTS) register clears the CAN Interrupt (CANINT) register, if it is
pending.
CAN Status (CANSTS)
CAN0 base: 0x4004.0000
Offset 0x004
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
reserved
Type RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
reserved
BOFF EWARN EPASS RXOK TXOK
LEC
Type RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
R/W
R/W
R/W
R/W
R/W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit/Field
31:8
7
6
5
Name
reserved
BOFF
EWARN
EPASS
Type
RO
RO
RO
RO
Reset Description
0x0000.00 Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
0
Bus-Off Status
0: CAN controller is not in bus-off state.
1: CAN controller is in bus-off state.
0
Warning Status
0: Both error counters are below the error warning limit of 96.
1: At least one of the error counters has reached the error warning limit
of 96.
0
Error Passive
0: The CAN module is in the Error Active state, that is, the receive or
transmit error count is less than or equal to 127.
1: The CAN module is in the Error Passive state, that is, the receive or
transmit error count is greater than 127.
June 19, 2012
529
Texas Instruments-Production Data