DCAN Control Registers
1103
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
Controller Area Network (DCAN) Module
23.17.21 IF1/IF2 Arbitration Registers (DCAN IF1ARB, DCAN IF2ARB)
The bits of the IF1/IF2 Arbitration Registers mirror the arbitration bits of a message object. The function of
the relevant message objects bits is described in
NOTE:
While the Busy bit in the IF1/IF2 Command Register is 1, IF1/IF2 Register Set is write
protected.
Figure 23-56. IF1 Arbitration Register (DCAN IF1ARB) [offset = 108h]
31
30
29
28
16
MsgVal
Xtd
Dir
ID[28:16]
R/WP-0
R/WP-0
R/WP-0
R/WP-0
15
0
ID[15:0]
R/WP-0
LEGEND: R/W = Read/Write; WP = Protected Write (protected by Busy bit); -
n
= value after reset
Figure 23-57. IF2 Arbitration Register (DCAN IF2ARB) [offset = 128h]
31
30
29
28
16
MsgVal
Xtd
Dir
ID[28:16]
R/WP-0
R/WP-0
R/WP-0
R/WP-0
15
0
ID[15:0]
R/WP-0
LEGEND: R/W = Read/Write; WP = Protected Write (protected by Busy bit); -
n
= value after reset
Table 23-23. IF1/IF2 Arbitration Register Field Descriptions
Bit
Field
Value
Description
31
MsgVal
Message Valid
0
The message object is ignored by the Message Handler.
1
The message object is used by the Message Handler.
Note: The CPU should reset the MsgVal bit of all unused Messages Objects during the
initialization before it resets bit Init in the CAN Control Register. MsgVal must also be reset if
the messages object is no longer used in operation. For reconfiguration of message objects
during normal operation, see
and
30
Xtd
Extended Identifier
0
The 11-bit ("standard") identifier is used for this message object.
1
The 29-bit ("extended") identifier is used for this message object.
29
Dir
Message direction
0
Direction = Receive: On TxRqst, a Remote Frame with the identifier of this message object is
transmitted. On receiving a Data Frame with a matching identifier, this message is stored in this
message object.
1
Direction = Transmit: On TxRqst, the respective message object is transmitted as a Data
Frame. On receiving a Remote Frame with a matching identifier, the TxRqst bit of this message
object is set (if RmtEn = 1).
28-0
ID[28:0]
Message Identifier
ID[28:0]
29-bit Identifier ("Extended Frame")
ID[28:18]
11-bit Identifier ("Standard Frame")