LM3S2776 Datasheet, PDF (651/785 Pages) Texas Instruments – Stellaris® LM3S2776 Microcontroller

Stellaris® LM3S2776 Microcontroller
Register 30: CAN Transmission Request 1 (CANTXRQ1), offset 0x100
Register 31: CAN Transmission Request 2 (CANTXRQ2), offset 0x104
The CANTXRQ1 and CANTXRQ2 registers hold the TXRQST bits of the 32 message objects. By
reading out these bits, the CPU can check which message object has a transmission request pending.
The TXRQST bit of a specific message object can be changed by three sources: (1) the CPU via the
CANIFnMCTL register, (2) the message handler state machine after the reception of a remote
frame, or (3) the message handler state machine after a successful transmission.
The CANTXRQ1 register contains the TXRQST bits of the first 16 message objects in the message
RAM; the CANTXRQ2 register contains the TXRQST bits of the second 16 message objects.
CAN Transmission Request 1 (CANTXRQ1)
CAN0 base: 0x4004.0000
Offset 0x100
Type RO, 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
TXRQST
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
Bit/Field
31:16
15:0
Name
reserved
TXRQST
Type
RO
RO
Reset
0x0000
0x0000
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.
Transmission Request Bits
0: The corresponding message object is not waiting for transmission.
1: The transmission of the corresponding message object is requested
and is not yet done.
November 17, 2011
651
Texas Instruments-Production Data