NXP Semiconductors PXN2020 - 26.7.5 Message Buffer Search on Simple Message Buffer Configuration; 26.7.5.1 Simple Message Buffer Configuration

FlexRay Communication Controller (FlexRAY)
PXN20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor 26-155
If the command execution block of the PE is idle, it selects the next accepted protocol command with the
highest priority from the current protocol command vector according to the protocol control command
priorities given in Table 26-119. If the current protocol state does not allow the execution of this protocol
command (see POC state changes in FlexRay Communications System Protocol Specification, Version 2.1
Rev A) the controller asserts the illegal protocol command interrupt flag IPC_IF in the Protocol Interrupt
Flag Register 1 (PIFR1). The protocol command is not executed in this case.
Some protocol commands may be interrupted by other commands or the detection of a fatal protocol error
as indicated by Table 26-119. If the application issues the FREEZE or READY command, or if the PE
detects a fatal protocol error, some commands already stored in the command vector will be removed from
this vector.
26.7.5 Message Buffer Search on Simple Message Buffer Configuration
This sections describes the message buffer search behavior for a simplified message buffer configuration.
The FIFO behavior is not considered in this section.
26.7.5.1 Simple Message Buffer Configuration
A simple message buffer configuration is a configuration that has at most one transmit message buffer and
at most one receive message buffer assigned to a slot S. The simple configuration used in this section
utilizes two message buffers, one single buffered transmit message buffer and one receive message buffer.
The transmit message buffer has the message buffer number t and has following configuration
Table 26-119. Protocol Control Command Priorities
Protocol Command Priority Interrupted By Cleared and Terminated By
FREEZE (highest) 1
none
READY 2
CONFIG_COMPLETE 3
ALL_SLOTS 4
FREEZE,
READY,
CONFIG_COMPLET,
fatal protocol error
FREEZE, READY, CONFIG_COMPLETE,
fatal protocol error
ALLOW_COLDSTART 5
RUN 6 FREEZE,
fatal protocol error
WAKEUP 7 FREEZE,
fatal protocol error
DEFAULT_CONFIG 8 FREEZE,
fatal protocol error
CONFIG 9
HALT (lowest) 10 FREEZE, READY, CONFIG_COMPLETE,
fatal protocol error