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FlexRay Communication Controller (FlexRAY)
PXN20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor
26-153
26.7.1.2
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 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 controller is configured as a FlexRay node and is ready to integrate into the
FlexRay cluster.
26.7.2
Shut Down Sequence
This section describes a secure shut down sequence to stop the controller 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 MBCCSR
n
[EDT] until MBCCSR
n
[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)
26.7.3
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
Summary of Contents for PXN2020
Page 1: ...PXN20 Microcontroller Reference Manual Devices Supported PXN2020 PXN2120 PXN20RM Rev 1 06 2011...
Page 42: ...PXN20 Microcontroller Reference Manual Rev 1 lxiv Freescale Semiconductor...
Page 64: ...Introduction PXN20 Microcontroller Reference Manual Rev 1 1 22 Freescale Semiconductor...
Page 112: ...Signal Description PXN20 Microcontroller Reference Manual Rev 1 3 44 Freescale Semiconductor...
Page 118: ...Resets PXN20 Microcontroller Reference Manual Rev 1 4 6 Freescale Semiconductor...
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Page 1376: ...Memory Map PXN20 Microcontroller Reference Manual Rev 1 A 118 Freescale Semiconductor...