NXP Semiconductors MPC5644A, Reference Manual, Page: 1571 / 1735

FlexRay Communication Controller (FlexRay)
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor 1571
The CC restricts its access to the regions, depending on the current state of the corresponding part of the
double transmit message buffer. The application must adhere to these restrictions in order to ensure data
consistency. The states for the commit side of a double transmit message buffer are given in
Figure 33-142 .
A description of the states is given in Table 33-118 . The states for the transmit side of a double transmit
message buffer are given in Figure 33-143 . A description of the states is given in Table 33-118 . The
description tables also provide the access scheme for the access regions.
The status bits FR_MBCCSRn[EDS] and FR_MBCCSRn[LCKS] provide the application with the
required message buffer status information. The internal status information is not visible to the application.
33.6.6.4.2 Message buffer states
This section describes the transmit message buffer states and provides a state diagram.
Figure 33-142. Double transmit message buffer state diagram (commit side)
A description of the states of the commit side of a double transmit message buffer is given in Table 33-117 .
Table 33-117. Double transmit message buffer state description (commit side)
State
FR_MBCCSR(2n) Access region
Description
EDS LCKS Appl. Module
Common states
HDis 0 0 CFG — Disabled – Message Buffer under configuration.
Commit Side can not be used for internal message transfer.
CCITx 1 0 — ITX Internal Message Transfer – Message Buffer Data
transferred from commit side to transmit side.
Commit side specific states
Idle 1 0 — ITX, SS Idle – Message Buffer Commit Side is idle.
Commit Side can be used for internal message transfer.
HDis
RESET_STATE
HD
HE
Idle
IS
IE
CCITx
HLck
HE
HL
HU
HDisLck
HU
HD
HL