CAN Control Registers
1602
SPRUHE8E – October 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
M3 Controller Area Network (CAN)
Table 23-25. IF3 Message Control Register Field Descriptions (continued)
Bit
Field
Value
Description
12
UMask
Use Acceptance Mask
0
Mask ignored
1
Use Mask (Msk[28:0], MXtd, and MDir) for acceptance filtering
If the UMask bit is set to one, the message object's mask bits have to be programmed during
initialization of the message object before MsgVal is set to one.
11
TxIE
Transmit Interrupt Enable
0
IntPnd will not be triggered after the successful transmission of a frame.
1
IntPnd will be triggered after the successful transmission of a frame.
10
RxIE
Receive Interrupt Enable
0
IntPnd will not be triggered after the successful reception of a frame.
1
IntPnd will be triggered after the successful reception of a frame.
9
RmtEn
Remote Enable
0
At the reception of a remote frame, TxRqst is not changed.
1
At the reception of a remote frame, TxRqst is set.
Note: See
for details on the setup of RmtEn and UMask for remote frames.
8
TxRqst
Transmit Request
0
This message object is not waiting for a transmission.
1
The transmission of this message object is requested and is not yet done.
7
EoB
End of Block
0
The message object is part of a FIFO Buffer block and is not the last message object of the FIFO
Buffer block.
1
The message object is a single message object or the last message object in a FIFO Buffer Block.
Note: This bit is used to concatenate multiple message objects to build a FIFO Buffer. For single
message objects (not belonging to a FIFO Buffer), this bit must always be set to one.
6-5
Reserved
Reserved
3-0
DLC[3:0]
Data length code
0-8
Data frame has 0-8 data bytes.
9-15
Data frame has 8 data bytes.
Note: The data length code of a message object must be defined the same as in all the
corresponding objects with the same identifier at other nodes. When the message handler stores a
data frame, it will write the DLC to the value given by the received message.
23.15.23 IF3 Data A and Data B Registers (CAN IF3DATA/DATB)
The data bytes of CAN messages are stored in the IF3 registers in the following order: in a CAN data
frame, Data 0 is the first, and Data 7 is the last byte to be transmitted or received. In CAN's serial bit
stream, the MSB of each byte will be transmitted first.
Figure 23-48. IF3 Data A Register (CAN IF3DATA) [offset = 0x150]
31
24
23
16
Data 3
Data 2
R-0
R-0
15
8
7
0
Data 1
Data 0
R-0
R-0
LEGEND: R = Read; -
n
= value after reset