• Rx Handler: Controls the transfer of received messages from the CAN Core to the
external Message RAM. The Rx Handler supports two Receive FIFOs, each of
configurable size, and up to 64 dedicated Rx Buffers for storage of all messages that
have passed acceptance filtering. A dedicated Rx Buffer, in contrast to a Receive
FIFO, is used to store only messages with a specific identifier. An Rx timestamp is
stored together with each message. Up to 128 filters can be defined for 11-bit IDs
and up to 64 filters for 29-bit IDs.
• Generic Slave Interface: Connects the M_CAN to a specific Host CPU. The Generic
Slave Interface is capable to connect to an 8/16/32-bit bus to support a wide range of
interconnection structures.
• Generic Master Interface: Connects the M_CAN access to an external 32-bit
Message RAM. The maximum Message RAM size is 16 KB × 32-bit.
• Extension Interface: All flags from the Interrupt Register IR as well as selected
internal status and control signals are routed to this interface. The interface is
intended for connection of the M_CAN to a module-external interrupt unit or other
module-external components. The connection of these signals is optional.
3.2.3 Dual Clock Sources
To improve the EMC behavior, a spread spectrum clock can be used for the Host clock
domain. Due to the high precision clocking requirements of the CAN Core, a separate
clock without any modulation has to be provided as CAN clock.
Within the M_CAN module there is a synchronization mechanism implemented to ensure
save data transfer between the two clock domains.
Note
In order to achieve a stable function of the M_CAN, the Host
clock must always be faster than or equal to the CAN clock.
Also, the modulation depth of a spread spectrum clock must be
regarded.
3.2.4 Dual Interrupt Lines
The module provides two interrupt lines. Interrupts can be routed either to M_CAN
interrupt 0 or to M_CAN interrupt 1. By default all interrupts are routed to interrupt line
M_CAN interrupt 0. By programming ILE[EINT0] and ILE[EINT1], the interrupt lines
can be enabled or disabled separately.
Overview
MPC5777C Reference Manual Addendum, Rev. 1, 12/2015
26 Freescale Semiconductor, Inc.
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