STLC5460 데이터 시트보기 (PDF) - STMicroelectronics
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STLC5460 Datasheet PDF : 54 Pages
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STLC5460
LINE CARD APPLICATIONS
The LCIC is designed to fit both digital and ana-
logue line card architectures.
It supports up to 16 ISDN subscribers or 16 voice
subscribers. The level 1 devices are connected to
ST5451 circuits to perform the D channel han-
dling.
Analogue Line Card
In analogue line cards LCIC controls signalling,
voice and data path of 64 kb/s channels.
When used in combination with L3040/L3000N, it
allows to implement an optimised line card archi-
tecture:
the LCIC controls the configuration of L3040 and
exchange signalling with the L3040.
Digital Line Card
In digital line cards LCIC controls the configura-
tion of Level 1 circuits (U or S Interface) by
means of MON channel configuration and per-
forms activation/deactivation by means of Com-
mand/Indicate protocol. LCIC switches the B
channels and can switch the D channels if the
processing is centralised.
FUNCTIONAL DESCRIPTION
PCM INTERFACE
The PCM Interface Registers configure the data
transmitted or received at the PCM port, for one
PCM, the maximum data rate can change de-
pending on the Mode selected:
PCM Mode 0: max rate 2048 kb/s with four PCM
ports active
PCM Mode 1: max rate 4096 kb/s with two PCM
ports active
PCM Mode 2: max rate 8192 kb/s with one PCM
ports active.
The ”actual data” rate may be varied in a wide
range without programming.
An automate computes the number of clock per
frame. Hence, the data rate can be stepped in 8,
16 or 32 kb/s in increments in PCM mode 0, 1, 2
respectively.
The clock frequency of PDC is equal to once or
twice the data rate, See fig 1 and 2. When operat-
ing at single rate (2048 kb/s) and not at double
clock frequency (4096 kHz), an onchip clock fre-
quency doubler provides a 4098 kHz clock for the
GCI interface (DCL).
The rising edge of PFS signal is used to deter-
mine the first bit of the first time slot of the frame.
The length of PFS pulse is one bit-time at least
and the length between two pulses can be also
one bit time.
After reset, the LCIC reaches synchronism having
received two consecutive correct PFS pulses.
Synchronisation is considered lost by the device if
the PFS signal is not repeated with the correct
repetition rate which has been stored by the cir-
cuit at the beginning of synchronisation research.
The LSYNC bit in the Interrupt Register indicates
if the component is synchronised or not: a logical
0 indicates the synchronous state, a logical ”1”
shows that the synchronism has been lost.
The relation between the framing signal PFS and
the bit stream is controlled by the contents of
IPOF, OPOF and CPOF registers. These regis-
ters denote the number of bit times the PCM
frame is shifted. Each PCM multiplex can be pro-
grammed with different shifts .
Without programming the bit shift function of the
PCM interface, the rising edge of the PFS signal
marks the first bit of input PCM frame and the
first bit of output PCM frame. See Fig 3
GCI Interface
The Monitor and the Command/Indicate channels
may be validated or not, in this second case the
B3 and B4 channels become standard channels
at 64 kb/s.
When validated Command/Indicate channel may
be configured with four bits for digital cards or six
bits for analogue cards.
The clocks (Bit clock and frame clock) are deliv-
ered by the device with double rate clocking or
simple rate clocking.
FSC and DCL are output signals derived from
PFS and PDC which are input signals.
GCI
DCL clock kHz
Simple (*)
Double
2.048
4.096
2.048
4.096
2.048
4.096
2.048
4.096
2.048
4.096
2.048
4.096
Data kb/s
2.048
2.048
2.048
2.048
2.048
2.048
PDC Clock (kHz)
Simple
Double
2.048
4.096
4.096
8.192
8.192
16.384
PCM
Data rate kb/s
2.048
2.048
4.096
4.096
8.192
8.192
Mode
Mode 0
Mode 0
Mode 1
Mode 1
Mode 2
Mode 2
(*) as GCI format but with simple clock.
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