K60P100M100SF2RM Datasheet, PDF (1368/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

Functional Description
The move-in process is not atomic, in such a way that it is immediately cancelled by the
inactivation of the destination Mailbox (see Section "Message Buffer Inactivation") and
in this case the Mailbox may be left partially updated, thus incoherent. The exception is if
the move-in destination is an Rx FIFO Message Buffer, then the process cannot be
cancelled.
The BUSY Bit (least significant bit of the CODE field) of the destination Message Buffer
is asserted while the move-in is being performed to alert the CPU that the Message
Buffer content is temporarily incoherent.
48.4.5.2 Move-out
The move-out process is the copy of the content from a Tx Mailbox to the Tx SMB when
a message for transmission is available (see Section "Arbitration process"). The move-out
occurs in the following conditions:
• the first bit of Intermission field;
• during Bussoff field when TX Error Counter is in the 124 to 128 range;
• during BusIdle field
• during Wait For Bus Idle field
The move-out process is not atomic. Only the CPU has priority to access the memory
concurrently out of BusIdle state. In BusIdle, the move-out has the lowest priority to the
concurrent memory accesses.
48.4.6 Data Coherence
In order to maintain data coherency and FlexCAN proper operation, the CPU must obey
the rules described in Transmit Process and Receive Process. Any form of CPU accessing
an MB structure within FlexCAN other than those specified may cause FlexCAN to
behave in an unpredictable way.
48.4.6.1 Transmission Abort Mechanism
The abort mechanism provides a safe way to request the abortion of a pending
transmission. A feedback mechanism is provided to inform the CPU if the transmission
was aborted or if the frame could not be aborted and was transmitted instead.
Two primary conditions must be fulfilled in order to abort a transmission:
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K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc.