mc9s12xf512 Freescale Semiconductor, Inc, mc9s12xf512 Datasheet - Page 570

• Manufacturer Part Number: mc9s12xf512
• Description: S12x Microcontrollers 16-bit Automotive Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Chapter 13 FlexRay Communication Controller (FLEXRAY)
Module Transitions
The module transitions that can be triggered by the FlexRay block are described in
transition will be triggered for certain message buffers when the related condition is fulfilled.
Transition Priorities
The application can trigger only one transition at a time. There is no need to specify priorities among them.
As shown in
For all states except the CCRx state, a module transition and the application lock/unlock transition HL/HU
and can be executed at the same time. The result state is reached by first applying the module transition
and subsequently the application transition to the intermediately reached state. For example, if the message
buffer is in the buffer subscribed state CCBs and the module triggers the slot start transition SLS at the
same time as the application locks the message buffer by the HL transition, the intermediate state is CCRx
and the resulting state is locked buffer subscribed state HLckCCRx.
13.6.6.3.2
As a result of the message buffer search, the FlexRay block changes the state of up to two enabled receive
message buffers from either idle state Idle or locked state HLck to the either subscribed state CCBs or
locked buffer subscribed state HLckCCBs by triggering the buffer subscribed transition BS.
If the receive message buffers for the next slot are assigned to both channels, then at most one receive
message buffer is changed to a buffer subscribed state.
If more than one matching message buffers assigned to a certain channel, then only the message buffer
with the lowest message buffer number is in one of the states mentioned above.
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Transition
CCRx
State
HLck
SNS
SSS
SLS
Idle
BS
SU
Table
Message Reception
symbol window start or
symbol window start or
CycleCounter match
SSS > HL
Priorities
BS > HD
BS > HD
13-102, the module transitions have a higher priority than the application transitions.
status updated
slot match and
slot start or
Condition
slot start
NIT start
NIT start
Table 13-102. Receive Message Buffer Transition Priorities
Table 13-101. Receive Message Buffer Module Transitions
Buffer Subscribed > Message Buffer Disable
Buffer Subscribed > Message Buffer Disable
Slot or Segment Start > Message Buffer Lock
MC9S12XF - Family Reference Manual, Rev.1.19
Buffer Subscribed - The message buffer filter matches next slot and cycle.
Slot Start - Start of either Static Slot or Dynamic Slot.
Symbol Window or NIT Start - Start of either Symbol Window or NIT.
Slot or Segment Start - Start of either Static Slot, Dynamic Slot, Symbol
Window, or NIT.
Status Updated - Slot Status field, message buffer status flags, header index
updated. Interrupt flag set.
module vs. application
Description
Description
Table
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13-101. Each