FlexRay Communication Controller (FLEXRAY)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
30-146
Freescale Semiconductor
Preliminary
30.7.1.2
Protocol Initialization
This section describes the protocol related initialization steps.
1. Configure the Protocol Engine.
a) issue CONFIG command via
Protocol Operation Control Register (POCR)
b) wait for
POC:config
in
Protocol Status Register 0 (PSR0)
c) configure the PCR0,..., PCR30 registers to set all protocol parameters
2. Configure the Message Buffers and FIFOs.
a) set the number of message buffers used and the message buffer segmentation in the
Buffer Segment Size and Utilization Register (MBSSUTR)
b) define the message buffer data size in the
Message Buffer Data Size Register (MBDSR)
c) configure each message buffer by setting the configuration values in the
Configuration, Control, Status Registers (MBCCSRn)
Message Buffer Cycle Counter Filter
Message Buffer Frame ID Registers (MBFIDRn)
d) configure the receive FIFOs
e) issue CONFIG_COMPLETE command via
Protocol Operation Control Register (POCR)
f) wait for
POC:ready
Protocol Status Register 0 (PSR0)
After this sequence, the FlexRay block is configured as a FlexRay node and is ready to integrate into the
FlexRay cluster.
30.7.2
Shut Down Sequence
This section describes a secure shut down sequence to stop the FlexRay block gracefully. The main targets
of this sequence are
•
finish all ongoing reception and transmission
•
do not corrupt FlexRay bus and do not disturb ongoing FlexRay bus communication
For a graceful shutdown the application shall perform the following tasks:
1. Disable all enabled message buffers.
a) repeatedly write 1 to MBCCSRn[EDT] until MBCCSRn[EDS] == 0.
2. Stop Protocol Engine.
a) issue HALT command via
Protocol Operation Control Register (POCR)
b) wait for
POC:halt
in
Protocol Status Register 0 (PSR0)
30.7.3
Number of Usable Message Buffers
This section describes the relationship between the number of message buffers that can be utilized and the
required minimum CHI clock frequency. Additional constraints for the minimum CHI clock frequency are
given in
Section 30.3, “Controller Host Interface Clocking
”.