Normal Mode; Sleep Mode - Xilinx CAN FD v2.0 Product Manual

Normal Mode

The core can enter Normal mode only if Sleep, Loopback, and Snoop bits are 0 in the MSR
IMPORTANT:
register.
In Normal mode, the core participates in bus communication by transmitting and receiving
messages.
In Normal mode, core does not store its own transmitted messages.
Note:
(Internal) Loopback Mode
This mode is used for diagnostic purposes.
IMPORTANT:
In Loopback mode, the core receives any messages that it transmits by an internal loopback
to the RX line and acknowledges them. Received messages are stored in receive buffers
based on ID match result. The core stores its own transmitted message (based on ID match
result) in mailbox buffers or sequential/FIFO buffers in Loopback mode.
It does not participate in normal bus communication and does not receive any messages
transmitted by other CAN nodes (the external TX line is ignored). It drives a recessive
bitstream on the CAN bus (external TX line).

Sleep Mode

The core enters Sleep mode from Configuration or Normal mode when the SLEEP bit is 1
in the MSR register, the CAN bus is idle, and there are no pending transmission requests.
The core enters Configuration mode when any configuration condition is satisfied. The core
enters Normal mode (clearing the SLEEP request bit in the MSR register and also clearing
the corresponding status bit) under the following (wake-up) conditions:
• Whenever the SLEEP bit is set to 0.
• Whenever the SLEEP bit is 1, and bus activity is detected.
• Whenever there is a new message for transmission.
Interrupts are generated when the core enters Sleep mode or wakes up from Sleep mode.
CAN FD v2.0
PG223 December 5, 2018 www.xilinx.com
Chapter 3: Designing with the Core
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