NXP Semiconductors
UM11040
Software user manual for SJA1105P, SJA1105Q, SJA1105R, SJA1105S
UM11040 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2020. All rights reserved.
User manual Rev. 2 — 5 February 2020
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Bit Symbol Description
383:380 SYTOUSYTH This parameter defines the minimum number of out-of-schedule clock masters needed to
convince the synchronization engine to switch from SYNC state to INTEGRATE state or
UNSYNC state, respectively.
379:378 SYPRIORITY Used to check the sync priority of input protocol control frames and to set the sync priority
field of output protocol control frames.
377:374 SYDOMAIN Used to check the sync domain of input protocol control frames and to set the sync
domain field of output protocol control frames.
373:370 STTH This parameter defines the minimum number of in-schedule clock masters needed to
keep the synchronization engine in STABLE state; if the number of in-schedule clock
masters remains below this value for as many cycles as defined by the NUMUNSTBCY
parameter, the synchronization engine switches to INTEGRATE state.
369:366 STTOINTTH This field defines the minimum number of out-of-schedule clock masters needed to
convince the synchronization engine to switch from STABLE state to INTEGRATE state.
365:355 PCFSZE This parameter determines the size, in bytes, of a PCF both on input as on output,
including: 6-byte destination MAC address, 6-byte source MAC address, 2-byte
EtherType field, and 4-byte frame checksum. This parameter is used to assemble output
PCFs by appending as many trailing zeroes as needed to achieve the configured frame
size. On input, the length of a PCF is expected to match the value of this parameter. If
not, the frame is dropped. The clock synchronization block executes this check. To have
a length limitation active for PCFs that pass through the switch, the MAXLEN field of the
respective VL Policing table entries must be used. The minimum required value for this
field is 64, the maximum allowed value is 2043.
354:351 PCFPRIORITY This parameter determines the priority of a PCF sourced by a switch configured as
compression master. It does not affect PCFs that are routed by the switch (even if the
switch is configured as a compression master). The value of this parameter must be
larger than the PRIORITY field of entries of the VL Forwarding Table or the VLANPMAP
values of the L2 Forwarding configuration block (or their respective dynamically changed
values) for a PCF to win the priority selection.
350:336 OBVWINSZ This parameter defines the value of the observation window used by the compression
master to collect and compress input protocol control frames. It is specified in multiples of
8 ns.
335:329 NUMUNSTBCY This value defines the number of cycles of low clique support (i.e. the number of in-
schedule clock masters that remain below the value of the STTH parameter) that can
pass before the synchronization engine switches to INTEGRATE state. If it is zero, the
synchronization engine will transit to INTEGRATE state at the end of the first acceptance
window while in STABLE state (if support is not provided for the clique).
328:322 NUMSTBCY This value defines the number of cycles of clique support (i.e. the number of in-
schedule clock masters meets the value of the SYTH parameter) needed to cause the
synchronization engine to transit from SYNC state to STABLE state. If it is zero, the
synchronization engine will transit to STABLE state at the end of the first acceptance
window while in SYNC state (if there is support for the clique). The parameter is only
used when the SYTOSTBEN flag is set.
321:295 MAXTRANSPCLK Determines the age at which a frame is processed by the compression master or the
sync engine. It is provided in multiples of 8 ns and must account for the maximum PCF
latency from synchronization masters or compression masters to this switch.
294:287 MAXINTEGCY Determines the maximum value of the integration cycle that the synchronization engine
will accept in input PCFs. If the IPCFRAMESY flag is set, this field determines the
maximum value of output PCFs generated by the switch.