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PRELIMINARY
INVERSE MULTIPLEXING OVER ATM
PM7340 S/UNI-IMA-8
DATA SHEET
PMC-2001723
ISSUE 3
INVERSE MULTIPLEXING OVER ATM
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
289
Figure 30
- 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 31. The transmit data stream
is an E1 frame with a single framing byte (FAS/NFAS in Figure 31) 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
31). The least significant bit of each time-slot is transmitted last (B8 in Figure 31).
The TSDATA[n] bit (B8 of TS31) before the framing byte is the least significant bit
of time-slot 31. In Figure 31, 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 31
- 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 32
- Channelized E1 Transmit Link Timing w/ Clock gapped How
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