
Chapter 13 FlexRay Communication Controller (FLEXRAY)
MC9S12XF - Family Reference Manual, Rev.1.19
596
Freescale Semiconductor
The application enables or disables the generation of the MTS on either channel by setting or clearing the
(MTSBCFR). If an MTS is to be transmitted in a certain communication cycle, the application must set
the MTE control bit during the static segment of the preceding communication cycle.
The MTS is transmitted over channel A in the communication cycle with number CYCCNT, if
Eqn. 13-16
Eqn. 13-17
Eqn. 13-18
The MTS is transmitted over channel B in the communication cycle with number CYCCNT, if
Eqn. 13-19
Eqn. 13-20
13.6.14 Sync Frame and Startup Frame Transmission
The transmission of sync frames and startup frames is controlled by the following register elds:
PCR18.key_slot_id: provides the number of the slot for sync or startup frame transmission
PCR11.key_slot_used_for_sync: indicates sync frame transmission
PCR11.key_slot_used_for_startup: indicates startup frame transmission
PCR12.key_slot_header_crc: provides header crc for sync frame or startup frame
Message Buffer with message buffer number n=PCR18.key_slot_id
The generation of the sync or startup frames depends on the current protocol state. In the POC:startup
state, the generation is independent of the message buffer setup; in the POC:normal active state, the
generation is affected by the current message buffer setup.
13.6.14.1 Sync Frame and Startup Frame Transmission in POC:startup
In the POC:startup state, the sync and startup frame transmission is independent of the message buffer
setup. If at least one of the indication bits PCR11.key_slot_used_for_sync or
PCR11.key_slot_used_for_startup is set, a Null Frame will be transmitted in the slot with slot number
PCR18.key_slot_id. The header CRC for this Null Frame is taken from PCR12.key_slot_header_crc. The
settings of the sync and startup frame indicators are taken from PCR11.key_slot_used_for_sync and
PCR11.key_slot_used_for_startup.
13.6.14.2 Sync Frame and Startup Frame Transmission in POC:normal active
In the POC:normal active state, the sync and startup frame transmission depends on the message buffer
setup. If at least one of the indication bits PCR11.key_slot_used_for_sync or
PSR0 PROTSTATE
[]
POC:normal active
=
MTSACRF MTE
[]
1
=
CYCCNT MTSACFR CYCCNTMSK
[]
∧
MTSACFR CYCCNTVAL
[] MTSACFR CYCCNTMSK
[]
∧
=
MTSBCRF MTE
[]
1
=
CYCCNT MTSBCFR CYCCNTMSK
[]
∧
MTSBCFR CYCCNTVAL
[] MTSBCFR CYCCNTMSK
[]
∧
=