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Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 563
UG585 (v1.11) September 27, 2016
Chapter 18: CAN Controller
18.2.2 Message Format
The same message format is used for RxFIFO and Tx (FIFO and HPB). 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 18-2. The details of each field are in
Table 18-3.
Bit Field Details
Writes
If a bit field or data byte is not required, then write zeros. Software should write the default values
shown in Table 18-3 for unused functions.
000XX X 100 0 0Configuration
0011XX 010 0 0Loop back
0 0 1010 001 0 0Sleep
0 0 1001 000 1 1Snoop
0 0 1000 000 1 0Normal
Table 18-1: CAN Controller Modes of Operation (Cont’d)
CAN
CPU_1x
PS Reset
(slcr)
Software Reset
Register (can.SRR)
Mode Select Register
(MSR) (Read/Write bits)
Status Register (SR)
(Read Only bits)
Operational
Mode
SRST
(CAN
Reset)
CEN
(CAN
Enable)
LBACK SLEEP SNOOP CONFIG LBACK SLEEP NORMAL SNOOP
Table 18-2: CAN Message Format
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Message
Identifier
[IDR}
ID[28:18]
STR/RTR
IDE
ID[17:0]
RTR
Data
Length
Code
[DLCR]
DLC[3:0] Reserved
Time Stamp
(Rx only, Reserved for Tx)
Data
Word 1
[DW1R]
DB0[7:0] DB1[7:0] DB2[7:0] DB3[7:0]
Data
Word 2
[DW2R]
DB4[7:0] DB5[7:0] DB6[7:0] DB7[7:0]