CAN FD v2.0
15
PG223 December 5, 2018
Chapter 2:
Product Specification
Software Reset Register (Address 0x0000)
Writing to the Software Reset register (SRR) places the core in Configuration mode. In
Configuration mode, the core drives recessive on the bus line and does not transmit or
receive messages. During power-up, the
CEN
and
SRST
bits are 0 and the
CONFIG
bit in the
Status register (SR) is 1. The Transfer Layer Configuration registers can be changed only
when the
CEN
bit in the SRR is 0. Mode Select register bits (except
SLEEP
and
SBR
) can be
changed only when the
CEN
bit is 0. If the
CEN
bit is changed during core operation, Xilinx
recommends resetting the core so that operation starts over.
Mode Select Register (Address 0x0004)
Writing to the Mode Select register (MSR) enables the core to enter Snoop, Sleep,
Loopback, or Normal modes. In Normal mode, the core participates in normal bus
communication. If the
SLEEP
bit is set to 1, the core enters Sleep mode. If the
LBACK
bit is
set to 1, the core enters Loopback mode. If the
SNOOP
mode is set to 1, the core enters
Snoop mode and does not participate in bus communication but only receives messages.
0x00F8
RSVD
Reserved
0x00FC
RSVD
Reserved
Notes:
1. These fields are only available when the IP is configured in FIFO (Sequential) Mode and RX FIFO-1 is enabled.
Table 2-4:
CAN FD Core Register Space
(Cont’d)
Start
Address 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
Name
(Reset
Value)
Table 2-5:
Software Reset Register
Bits
Name
Access Default
Value
Description
31:2
Reserved
–
0
Reserved.
1
CEN
R/W
0
CAN Enable.
This is the Enable bit for the core.
• 1 = The core is in Loopback, Sleep, Snoop, or Normal mode,
depending on the LBACK, SLEEP, and SNOOP bits in the MSR.
• 0 = The core is in Configuration mode.
Note:
If the CEN bit is cleared during core operation, Xilinx recommends
resetting the core so that operation starts over.
0
SRST
WO
0
Reset.
This is the software reset bit for the core.
• 1 = Core is reset.
If a 1 is written to this bit, all core configuration registers
(including the SRR) are reset. Reads to this bit always return 0.
Note:
After performing a soft or hard reset, wait for 16 AXI4-Lite/APB
clock cycles before initiating next AXI4-Lite/APB transaction.