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PRELIMINARY
INVERSE MULTIPLEXING OVER ATM
PM7341 S/UNI-IMA-84
DATASHEET
PMC-2000223
ISSUE 4
INVERSE MULTIPLEXING OVER ATM
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
387
Figure 34
- Channelized T1 Transmit Link Timing w/ Clock gapped high
TSCLK[n]
TSDATA[n]
B7 B8
B1 B2 B3 B4 B5 B6 B7 B8 B1 B2 B3
TS 24
TS 1
TS 2
F
The timing relationship of the transmit clock (TSCLK[n]) and data (TSDATA[n])
signals of a channelized E1 link is shown in Figure 35. The transmit data stream
is an E1 frame with a single framing byte (FAS/NFAS in Figure 35) followed by
octet bound time-slots 1 to 31. TSCLK[n] is held quiescent during the framing
byte. The most significant bit of each time-slot is transmitted first (B1 in Figure
35). The least significant bit of each time-slot is transmitted last (B8 in Figure 35).
The TSDATA[n] bit (B8 of TS31) before the framing byte is the least significant bit
of time-slot 31. In Figure 35, the quiescent period is shown to be a low level on
TSCLK[n]. A high level, effected by extending the high phase of bit B8 of time-slot
31, is equally acceptable. In channelized E1 mode, TSCLK[n] can only be
gapped during the framing byte. It must be active continuously at 2.048 MHz
during all time-slot bits. Time-slots that are not provisioned to belong to any
channel
i.e., the PROV bit in the corresponding word of the transmit channel
provision RAM in the TCAS block is set low
transmit the contents of the Idle
Time-slot Fill Data register.
Figure 35
- Channelized E1 Transmit Link Timing w/ Clock gapped Low
TSCLK[n]
TSDATA[n]
B6 B7
B1
B2 B3
TS 31
FAS / NFAS
TS 1
B8
B4 B5 B6 B7 B8 B1 B2 B3 B4
TS 2
Figure 36
- Channelized E1 Transmit Link Timing w/ Clock gapped High
TSCLK[n]
TSDATA[n]
B6 B7
B1 B2 B3
TS 31
FAS / NFAS
TS 1
B8
B4 B5 B6 B7 B8 B1 B2 B3 B4
TS 2