PXS20RM Datasheet, PDF (604/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

FlexCAN Module
24.1.3.5 Module Disable Mode:
This low power mode is entered when the MDIS bit in the MCR Register is asserted. When disabled, the
module shuts down the clocks to the CAN Protocol Interface and Message Buffer Management
sub-modules. Exit from this mode is done by negating the MDIS bit in the MCR Register. See
Section 24.4.9.2, Module Disable Mode, for more information.
24.1.3.6 Stop Mode
This low power mode is entered when Stop Mode is requested at MCU level. 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 or when activity is detected on the
CAN bus and the Self Wake Up mechanism is enabled. See Section 24.4.9.3, Stop Mode, for more
information.
24.2 External signal description
The FlexCAN module has two I/O signals connected to the external MCU pins. These signals are
summarized in Table 24-1 and described in more detail in the next subsections.
Table 24-1. FlexCAN signals
Signal Name¹
Direction
Description
CAN Rx
CAN Tx
Input
Output
CAN Receive Pin
CAN Transmit Pin
NOTES:
1 _{The actual MCU pins may have different names. Please consult the Device User Guide for the}
actual signal names.
24.2.1 CAN Rx
This pin is the receive pin from the CAN bus transceiver. Dominant state is represented by logic level ‘0’.
Recessive state is represented by logic level ‘1’.
24.2.2 CAN Tx
This pin is the transmit pin to the CAN bus transceiver. Dominant state is represented by logic level ‘0’.
Recessive state is represented by logic level ‘1’.
24.3 Memory map and register definition
This section describes the registers and data structures in the FlexCAN module. The base address of the
module depends on the particular memory map of the MCU. The addresses presented here are relative to
the base address.
The address space occupied by FlexCAN has 96 bytes for registers starting at the module base address,
followed by MB storage space in embedded RAM starting at address 0x0060, and an extra ID Mask
storage space in a separate embedded RAM starting at address 0x0880.
24-4
PXS20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor