Datasheet
____________________________________________________ DS34T101, DS34T102, DS34T104, DS34T108
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Figure 10-30. T1 ESF Interface RSIG Timing Diagram (two_clocks=0)
TDMn_TCLK
TDMn_RX_SYNC
TDMn_RSIG
A B C D A B C D A B C D
Timeslot 22 Timeslot 23 Timeslot 0
Once in 3milliseconds
Figure 10-31. T1 SF Interface RSIG (two_clocks=0) – Timing Diagram
TDMn_TCLK
TDMn_RX_SYNC
TDMn_RSIG
A B A B A B A B A B A B
Timeslot 22 Timeslot 23 Timeslot 0
Once in 1.5 milliseconds
TDMn_RX_SYNC can be left unconnected or connected to ground if the framer cannot drive it. The TDMoP block
has an internal free running counter that generates this signal internally when not driven by an external source.
This internally generated multiframe sync signal is synchronized to the TDMn_RX_SYNC input pulse when
present.
10.6.5.2
CAS Handler, Ethernet-to-TDM Direction
In the Ethernet-to-TDM direction, the CAS is received from the incoming packets.
The AAL1/RAW payload type machine extracts the CAS bits from the TDM-over-packet payload and writes them
into the CAS jitter buffers in the SDRAM (for structured-with-CAS AAL1/CESoPSN bundles only). The CAS jitter
buffers store the CAS information of up to 128 timeslots of the eight ports.
Selectors in the CAS handler send the CAS bits either from the CAS jitter buffers or from the Receive SW CAS
tables to the l
ine (next MF) CAS tables (see Figure 10-32). The selectors’ de
cision logic is shown in Table 10-20.
Table 10-20. CAS Handler Selector Decision Logic
Condition
Source of CAS bits Driven on
TDMn_TSIG_CTS for this Timeslot
Timeslot not assigned or assigned to a bundle which is not an
AAL1/CESoPSN structured bundle (Rx_assigned=0
or
Structured_type=0 for its
TSA entry)
AAL1 bundle jitter buffer is in underrun state and
Rx_CAS_src=1
Receive SW CAS tables
Timeslot assigned to an AAL1/CESoPSN structured bundle
(Rx_assigned=1 and Structured_type=1 for its
TSA entry)
AAL1/CESoPSN bundle jitter buffer is in underrun state and
Rx_CAS_src=0
Corresponding CAS jitter buffer in SDRAM (CAS value is
the latest received)