DCAN Registers
23.4.35 IF1ARB Register (offset = 108h) [reset = 0h]
IF1ARB is shown in
and described in
The bits of the IF1 arbitration registers mirror the arbitration bits of a message object. While Busy bit of IF1
command register is one, IF1 register set is write protected.
Figure 23-53. IF1ARB Register
31
30
29
28
27
26
25
24
MsgVal
Xtd
Dir
ID28_to_ID0
R/WP-0h
R/WP-0h
R/WP-0h
R/WP-0h
23
22
21
20
19
18
17
16
ID28_to_ID0
R/WP-0h
15
14
13
12
11
10
9
8
ID28_to_ID0
R/WP-0h
7
6
5
4
3
2
1
0
ID28_to_ID0
R/WP-0h
LEGEND: R/W = Read/Write; R = Read only; W1toCl = Write 1 to clear bit; -n = value after reset
Table 23-48. IF1ARB Register Field Descriptions
Bit
Field
Type
Reset
Description
31
MsgVal
R/WP
0h
Message valid.
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.
This bit must also be reset before the identifier ID28 to ID0, the
control bits Xtd, Dir or DLC3 to DLC0 are modified, or if the
messages object is no longer required.
0x0 = The message object is ignored by the message handler.
0x1 = The message object is to be used by the message handler.
30
Xtd
R/WP
0h
Extended identifier
0x0 = The 11-bit (standard) Identifier is used for this message object.
0x1 = The 29-bit (extended) Identifier is used for this message
object.
29
Dir
R/WP
0h
Message direction
0x0 = Direction = receive: On TxRqst, a remote frame with the
identifier of this message object is transmitted. On reception of a
data frame with matching identifier, this message is stored in this
message object.
0x1 = Direction = transmit: On TxRqst, the respective message
object is transmitted as a data frame. On reception of a remote
frame with matching identifier, the TxRqst bit of this message object
is set (if RmtEn = 1).
28-0
ID28_to_ID0
R/WP
0h
Message identifier.
ID28 to ID0 is equal to 29 bit identifier (extended frame) ID28 to ID18
is equal to 11 bit identifier (standard frame)
3963
SPRUH73H – October 2011 – Revised April 2013
Controller Area Network (CAN)
Copyright © 2011–2013, Texas Instruments Incorporated