Freescale Semiconductor FlexRay MFR4310 - Figure 3-119. Message Reception Timing

FlexRay Module (FLEXRAYV4)
MFR4310 Reference Manual, Rev. 2
166 Freescale Semiconductor
NOTE
If the number of the last slot in the current communication cycle on a given
channel is n, all receive message buffers assigned to this channel with
MBFIDRn.FID greater than n are not updated at all.
When the receive message buffer update has finished the status updated transition SU is triggered, which
changes the buffer state from CCSu to Idle. An example receive message buffer timing and state change
diagram for a normal frame reception is given in Figure 3-119.
Figure 3-119. Message Reception Timing
The amount of message data written into the message buffer data field of the receive shadow buffer is
determined by the following two items:
1. the message buffer segment that the message buffer is assigned to, as defined by the Message
Buffer Segment Size and Utilization Register (MBSSUTR).
2. the message buffer data field size, as defined by the related field of the Message Buffer Data Size
Register (MBDSR)
3. the number of bytes received over the FlexRay bus
If the message buffer is assigned to the message buffer segment 1, and the number of received bytes is
greater than 2*MBDSR.MBSEG1DS, the FlexRay module writes only 2*MBDSR.MBSEG1DS bytes
into the message buffer data field of the receive shadow buffer. If the number of received bytes is less than
2*MBDSR.MBSEG1DS, the FlexRay module writes only the received number of bytes and does not
change the trailing bytes in the message buffer data field of the receive shadow buffer. The same holds for
the message buffer segment 2 with MBDSR.MBSEG2DS.
0xNo valid frame received.
- Message Buffer Data Field not updated.
- Frame Header Field not updated.
- Slot Status Field updated.
- DUP:= 0
- DVAL not changed.
- MBIF:= 1, if the slot was not an empty dynamic slot.
Note: An empty dynamic slot is indicated by the following frame and slot
status bit values:
vSS!ValidFrame = 0 and vSS!SyntaxError = 0 and
vSS!ContentError = 0 and vSS!BViolation = 0.
Table 3-100. Receive Message Buffer Update (Continued)
vSS!ValidFrame vRF!Header!NFIndicator Update description
search[s+1]
MT st
a
rt
BS
slot s
SLS
SU
CCBs CCRx
slot s+1
Idle
MT start
Idle
slot s+2
slot start slot start
MT st
a
rt
message receive to receive shadow buffer
SSS
CCSu
slot start