FlexRay Module (FLEXRAYV2)
MFR4300 Data Sheet, Rev. 1
178
Freescale Semiconductor
CCFM = ‘0’ to indicate the slot assignment and to trigger the null frame transmission. In case of an receive
message buffer, this buffer is
not
added to the matching message buffer list.
A message buffer matches its cycle counter filter for the communication cycle with the number CCN if at
least one of the following conditions evaluates to true:
Eqn. 3-8
Eqn. 3-9
3.4.7.1.3
Message Buffer Channel Assignment Consistency
The message buffer channel assignment given by the CHA and CHB bits in the
Message Buffer Cycle
Counter Filter Registers (MBCCFRn)
defines the channels on which the message buffer will receive or
transmit.
The message buffer with number
n
transmits or receives on channel A if MBCCFRn.CHA = ‘1’
and transmits or receives on channel B if MBCCFRn.CHB = ‘1’.
To ensure correct message buffer operation, all message buffers assigned to the same slot must have a
consistent
channel assignment. That means that
all
message buffers assigned to the
same
slot must be
either assigned to
only
one channel, or assigned to
both
channels. The behavior of the message buffer
search is not defined, if both types of channel assignments occur for one slot. An inconsistent channel
assignment for message buffer 0 and message buffer 1 is depicted in
Figure 3-127
.
Figure 3-127. Inconsistent Channel Assignment
3.4.8
Individual Message Buffer Reconfiguration
The initial configuration of each individual message buffer can be changed even when the protocol is not
in the
POC:config
state. This is referred to as individual message buffer
reconfiguration
. The
configuration bits and fields that can be changed are given in the section on
Specific Configuration Data
.
The common configuration data given in the section on
Specific Configuration Data
can not be
reconfigured when the protocol is out of the
POC:config
state.
3.4.8.1
Reconfiguration Schemes
Depending on the target and destination basic state of the message buffer that is to be reconfigured, there
are three reconfiguration schemes.
3.4.8.1.1
Basic Type Not Changed (RC1)
A reconfiguration will not change the basic type of the individual message buffer, if both the message
buffer transfer direction bit MBCCSn.MTD and the message buffer type bit MBCCSn.MBT are not
changed. This type of reconfiguration is denoted by RC1 in
Figure 3-128
. Single transmit and receive
MBCCFRn.CCFE == 0
CCN[5:0] & MBCCFRn.CCFMSK[5:0] == MBCCFRn.CCFVAL[5:0] & MBCCFRn.CCFMSK[5:0]
MB0
MBCCFR0.CHA = 1, MBCCFR0.CHB = 0
MB1
dual channel assignment
single channel assignment
MBFIDR0.FID = 10
MBFIDR1.FID = 10
MBCCFR1.CHA = 1, MBCCFR1.CHB = 1