NXP Semiconductors MWCT101 S Series, Reference Manual

Page: 1571 / 1761

In this mode, FlexCAN is capable of transmitting and receiving all messages
formatted according to the CAN FD Protocol and CAN 2.0 Protocol 2.0 in an
interleaved fashion. The CPU can set the FlexCAN into CAN FD Active mode by
configuring MCR[FDEN] in Freeze mode.
It is important to know which features are available in CAN FD active mode. This
table lists the differences between FD and classical modes.
Table 49-3. Differences between CAN classical and CAN
FD
Feature CAN classical CAN FD
Rx FIFO DMA Yes No
Rx FIFO Yes No
Pretended network support Yes No
For low-power operation, the FlexCAN module has:
• Module Disable mode:
This low-power mode is entered when MCR[MDIS] is asserted by the CPU and
MCR[LPM_ACK] is asserted by FlexCAN. When disabled, the module issues a
request to disable the clocks to the CAN Protocol Engine and Controller Host
Interface submodules. Exit from this mode is done by negating MCR[MDIS]. See
Module Disable mode for more information.
• Stop mode:
This low power mode is entered when Stop mode is requested at chip level and
MCR[LPM_ACK] is asserted by the FlexCAN. When in Stop Mode, the module puts
itself in an inactive state and then informs the CPU that the clocks can be shut down
globally. Exit from this mode happens when the Stop mode request is removed. See
Stop mode for more information.
• Pretended Network mode:
This mode can be selected to operate together with Stop mode. Before entering in
one of these low power modes you must assert MCR[PNET_EN]. When in low
power mode, CHI sub-block clocks are shut down and CAN_PE sub-block is kept
clocked, so that the Rx receive process is still active to filter incoming messages (see
Receive process under Pretended Networking mode ) as defined by the configuration
registers (see Pretended Networking Control 1 Register (CTRL1_PN)). Upon
detecting a wakeup event, a Wake Up interrupt is issued to the system.
Chapter 49 FlexCAN
MWCT101xS Series Reference Manual, Rev. 3, 07/2019
NXP Semiconductors 1571