Message Format

Zynq UltraScale+ Device Technical Reference Manual (UG1085)

Document ID
UG1085
Release Date
2022-09-15
Revision
2.3 English

The same message format is used for RXFIFO, TXFIFO, and TXHPB. Each message includes four words (16 bytes). Software must read and write all four words regardless of the actual number of data bytes and valid fields in the message.

The message words, fields, and structure are shown in Table: CAN Message Format.

Table 20-3:      CAN Message Format

Message Word Registers

Description

Bits

Bit Field

Name

Frame Types

Data

Remote

Frame Size

Standard

Extended

Default

Value

Identifier:

{RXFIFO, TXFIFO, TXHPB}_ID

 

 

 

 

 

 

 

Remote transmission request

0

[RTR]

= 0

= 1

NA, = 0

Applies

0

Extended message frame ID

18:1

[IDL]

Valid

Valid

NA

Applies

0

Identifier extension for frame size

19

[IDE]

Valid

Valid

= 0

= 1

0

Substitute remote transmission request

20

[SRRRTR]

= 0

= 1

Applies

NA, = 1

0

Standard message frame ID

31:21

[IDH]

Valid

Valid

Applies

Applies

0

Data Length Code (DLC):

{RXFIFO, TXFIFO, TXHPB}_DLC

 

 

 

 

 

 

 

Data length code, 0 to 8 bytes

31:28

[DLC]

Valid

Valid

Valid

Valid

0

Reserved

27:0

~

~

~

~

~

0

Timestamp (RXFIFO only)

15:0

[RXT]

 

 

 

 

 

Data Word 1:

{RXFIFO, TXFIFO, TXHPB}_DATA1

 

 

 

 

 

 

 

Data Byte 0

31:24

[DB0]

Valid

Valid

Valid

Valid

0

Data Byte 1

23:16

[DB1]

Valid

Valid

Valid

Valid

0

Data Byte 2

15:8

[DB2]

Valid

Valid

Valid

Valid

0

Data Byte 3

7:0

[DB3]

Valid

Valid

Valid

Valid

0

Data Word 2:

{RXFIFO, TXFIFO, TXHPB}_DATA2

 

 

 

 

 

 

 

Data Byte 4

31:24

[DB4]

Valid

Valid

Valid

Valid

0

Data Byte 5

23:16

[DB5]

Valid

Valid

Valid

Valid

0

Data Byte 6

15:8

[DB6]

Valid

Valid

Valid

Valid

0

Data Byte 7

7:0

[DB7]

Valid

Valid

Valid

Valid

0