Message Interface Registers - Altera cyclone V Technical Reference

cv_5v4
2016.10.28
Message Identifier (ID[28:0])
Extended Frame Identifier (Xtd)
Message Direction (Dir)
Data Length Code (DLC[3:0])
Data Bytes 0-7 (Data 0[7:0] - Data 7[7:0])
Message Identifier (
•
ID28-ID0
•
ID28-ID18
Extended Frame 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.
Message Direction (
• 0= receive direction. When
is transmitted. On reception of a data frame with matching identifier, that message is stored in this
message object.
• 1= transmit direction. When
frame. On reception of a remote frame with matching identifier, the
set to 1 (if
Data Length Code (
DLC specifies the number of data bytes in the data frame. The maximum number is eight.
The data length code (
objects with the same identifier in all CAN devices. When the message handler stores a data frame, it sets
the field to the value provided in the received message.
DLC
Data Bytes 0-7 (
The data bytes in a CAN data frame.

Message Interface Registers

There are two sets of message interface registers,
DMA controller to access any message object indirectly. Message objects are transferred between the
message RAM and the message buffer registers as a single, atomic operation maintaining data consistency
across the message.
Table 25-2: Message Interface Register Set
This table lists the structure of each message interface register set, where x represents either set 1 or set 2.
Register Type
Command
CAN Controller
Send Feedback
on page 25-7
on page 25-7
on page 25-7
on page 25-7
)
ID[28:0]
: 29-bit identifier (extended frame)
: 11-bit identifier (standard frame)
)
Xtd
)
Dir
TxRqst
TxRqst
= 1).
RmtEn
)
DLC[3:0]
) of a message object must be defined the same as in all the corresponding
DLC
Data 0[7:0] - Data 7[7:0]
Register
IFx command
IFxCMR
register
on page 25-7
is set to 1, a remote frame with the identifier of this message object
is set to 1, the respective message object is transmitted as a data
)
and , that provide a means for a host processor or
IF1 IF2
Name
Specifies the transfer direction and selects the
portions of the message object to transfer
Message Identifier (ID[28:0])
bit of this message object is
TxRqst
Description
Altera Corporation
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