PXN20RM Datasheet, PDF (896/1376 Pages) Freescale Semiconductor, Inc – PXN20 Microcontroller

Controller Area Network (FlexCAN)
Table 29-7. CANx_MCR Field Descriptions
Field
Description
MDIS
Module Disable. Controls whether FlexCAN is enabled or not. When disabled, FlexCAN shuts down the clock to
the CAN protocol interface and message buffer management submodules. This is the only bit in CANx_MCR not
affected by soft reset. See Section 29.4.8.2, Module Disabled Mode, for more information.
0 Enable the FlexCAN module.
1 Disable the FlexCAN module.
FRZ
Freeze Enable. Specifies the FlexCAN behavior when the HALT bit in the CANx_MCR is set or when debug
mode is requested at MCU level. When FRZ is set, FlexCAN is enabled to enter freeze mode. Clearing this bit
causes FlexCAN to exit from freeze mode.
0 Not enabled to enter freeze mode.
1 Enabled to enter freeze mode.
FEN
FIFO Enable. controls whether the FIFO feature is enabled or not. When FEN is set, MBs 0 to 7 cannot be used
for normal reception and transmission because the corresponding memory region (0x80–0xFF) is used by the
FIFO engine. See Section 29.3.3, Rx FIFO Structure, and Section 29.4.6, Rx FIFO, for more information.
0 FIFO not enabled.
1 FIFO enabled.
HALT
Halt FlexCAN. Assertion of this bit puts the FlexCAN module into freeze mode if FRZ is asserted. The CPU
clears it after initializing the message buffers and CANx_CTRL. If FRZ is set, no reception or transmission is
performed by FlexCAN before this bit is cleared. While in freeze mode, the CPU has write access to the
CANx_ECR, that is otherwise read-only. Freeze mode cannot be entered while FlexCAN is disabled. See
Section 29.4.8.1, Freeze Mode, for more information.
0 No freeze mode request.
1 Enters freeze mode if the FRZ bit is asserted.
NOT_RDY
FlexCAN Not Ready. Indicates that FlexCAN is either disabled or in freeze mode. This flag is cleared once
FlexCAN has exited these modes.
0 FlexCAN module is in normal mode, listen-only mode, or loop-back mode.
1 FlexCAN module is either disabled or in freeze mode.
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PXN20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor