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FlexRay Module (FLEXRAYV2)
MFR4300 Data Sheet, Rev. 1
190
Freescale Semiconductor
Eqn. 3-17
The MTS is transmitted over channel B in the communication cycle with number CCN, if
Equation 3-15
,
Equation 3-18
, and
Equation 3-19
are fulfilled.
Eqn. 3-18
Eqn. 3-19
3.4.14
Sync Frame and Startup Frame Transmission
The transmission of sync frames and startup frames is controlled by the following register fields:
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.
3.4.14.1
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.
3.4.14.2
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
PCR11.key_slot_used_for_startup is set, or if a transmit message buffer with MBFIDRn.FID ==
PCR18.key_slot_id is configured and enabled, a Null Frame or Data Frame will be transmitted in the slot
with slot number PCR18.key_slot_id. The header CRC for this 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. A data frame will be transmitted
if the message buffer is unlocked and committed and the cycle counter filter matches the current cycle.
3.4.15
Sync Frame Filtering
Each received synchronization frame must pass the Sync Frame Acceptance Filter and the Sync Frame
Rejection Filter before it is considered for clock synchronization. If the synchronization frame filtering is
CC
N[5:0] & MTSACFR.CCFMSK[5:0]== MTSACFR.CCFVAL[5:0] & MTSACFR.CCFMSK[5:0]
MTSBCFR.MTE = 1
CC
N[5:0] & MTSBCFR.CCFMSK[5:0] = MTSBCFR.CCFVAL[5:0] & MTSBCFR.CCFMSK[5:0]