Datasheet

____________________________________________________ DS34S101, DS34S102, DS34S104, DS34S108
Rev: 032609 52 of 198
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 neighboring E1/T1 framer IC 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 line (next MF) CAS tables (see Figure 10-32). The selectors’ decision 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)
Receive SW CAS tables
AAL1 bundle jitter buffer is in underrun state and
Rx_CAS_src=1
Timeslot assigned to an AAL1/CESoPSN structured bundle
(Rx_assigned=1 and Structured_type=1 for its TSA entry)
Corresponding CAS jitter buffer in SDRAM (CAS value is
the latest received)
AAL1/CESoPSN bundle jitter buffer is in underrun state and
Rx_CAS_src=0