Message Interface Register Sets
1433
SPNU563A – March 2018
Copyright © 2018, Texas Instruments Incorporated
Controller Area Network (DCAN) Module
27.6 Message Interface Register Sets
Accesses to the Message RAM are performed via the Interface Register sets:
•
Interface Register 1 and 2 (IF1 and IF2)
•
Interface Register 3 (IF3)
The IF3 register set can be configured to automatically receive control and user data from the Message
RAM when a message object has been updated after reception of a CAN message. The CPU does not
need to initiate the transfer from Message RAM to IF3 register set.
The Message Handler avoids potential conflicts between concurrent accesses to Message RAM and CAN
frame reception/transmission.
There are two modes where the Message RAM can be directly accessed by the CPU:
1. In Debug/Suspend mode (see
)
2. In RAM Direct Access (RDA) mode (see
For the Message RAM Base address, refer to the device datasheet.
A complete message object (see
) or parts of the message object may be transferred
between the Message RAM and the IF1/IF2 Register set (see
) in one single transfer.
27.6.1 Message Interface Register Sets 1 and 2
The Interface Register sets IF1 and IF2 provide indirect read/write access from the CPU to the Message
RAM. The IF1 and IF2 register sets can buffer control and user data to be transferred to and from the
message objects.
Table 27-4. Message Interface Register Sets 1 and 2
Address
IF1 Register Set
Address
IF2 Register Set
[CAN Base +] 31
16 15
0 [CAN Base +] 31
16 15
0
0x100
IF1 Command Mask
IF1 Command
Request
0x120
IF2 Command Mask
IF2 Command
Request
0x104
IF1 Mask 2
IF1 Mask 1
0x124
IF2 Mask 2
IF2 Mask 1
0x108
IF1 Arbitration 2
IF1 Arbitration 1
0x128
IF2 Arbitration 2
IF2 Arbitration 1
0x10C
Rsvd
IF1 Message Control
0x12C
Rsvd
IF2 Message Control
0x110
IF1 Data A 2
IF1 Data A 1
0x130
IF2 Data A 2
IF2 Data A 1
0x114
IF1 Data B 2
IF1 Data B 1
0x134
IF2 Data B 2
IF2 Data B 1