LM3S5737 Datasheet, PDF (644/833 Pages) Texas Instruments – Stellaris® LM3S5737 Microcontroller

Controller Area Network (CAN) Module
Register 8: CAN IF1 Command Request (CANIF1CRQ), offset 0x020
Register 9: CAN IF2 Command Request (CANIF2CRQ), offset 0x080
A message transfer is started as soon as there is a write of the message object number to the MNUM
field when the TXRQST bit in the CANIF1MCTL register is set. With this write operation, the BUSY
bit is automatically set to indicate that a transfer between the CAN Interface Registers and the
internal message RAM is in progress. After a wait time of 3 to 6 CAN_CLK periods, the transfer
between the interface register and the message RAM completes, which then clears the BUSY bit.
CAN IF1 Command Request (CANIF1CRQ)
CAN0 base: 0x4004.0000
Offset 0x020
Type R/W, reset 0x0000.0001
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
BUSY
reserved
MNUM
Type RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
R/W
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
1
Bit/Field
31:16
15
14:6
5:0
Name
reserved
BUSY
reserved
MNUM
Type
RO
RO
RO
R/W
Reset
0x0000
0
0x00
0x01
Description
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.
Busy Flag
0: Cleared when read/write action has finished.
1: Set when a write occurs to the message number in this register.
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.
Message Number
Selects one of the 32 message objects in the message RAM for data
transfer. The message objects are numbered from 1 to 32.
Value
0x00
0x01-0x20
0x21-0x3F
Description
Reserved
0 is not a valid message number; it is interpreted
as 0x20, or object 32.
Message Number
Indicates specified message object 1 to 32.
Reserved
Not a valid message number; values are shifted and
it is interpreted as 0x01-0x1F.
644
November 17, 2011
Texas Instruments-Production Data