STLC5466 datasheet(20/130 Pages) STMICROELECTRONICS

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STLC5466

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The GCI or V* channels are composed of 4 bytes

and have both the same general structure.

Only Monitor handshakes and S/C bytes are dif-

ferent in the three protocols:

ISDN V* S/C byte

ISDN GCI S/C byte

Analog GCI S/C byte

In GCI protocol, A and E are the handshake bits

and are used to control the transfer of information

on monitor channels.The E bit indicates the trans-

fer of each new byte in one direction and the A bit

acknowledges this byte transfer in the reverse di-

rection.

protocol,

there

isn’t

any

handshake

mode.The transmitter has only to mark the validity

of the Monitor byte by positioning the E bit (T is not

used and is forced to “1”).

For more information about the GCI and V*, refer

to the General Interface Circuit Specification

(issue1.0, march 1989) and the France Telecom

Specification about ISDN Basic Access second

generation (November 1990).

III.3.3 - Structure of the Treatment

In reception GCI/V* TDM’s are connected to DIN 4

and DIN 5. The D channels are switched through

the matrix towards the output 7 and output6 then

towards the HDLC receivers. The Monitor and S/C

bytes are multiplexed and sent to the CI and Mon-

itor receivers.

In transmission, the S/C and Monitor bytes are re-

combined by multiplexing the information provided

by the Monitor, C/I and the HDLC Transmitter.

Like in reception, the D channel is switched

through the matrix (input 7 towards DOUT 4 and

DOUT 5).

III.3.4 - CI and Monitor Channel Configuration

Monitor channel data is located in a time slot; the

CI and monitor handshake bits are in the next time

slot.

Each channel can be defined independently. A ta-

ble with all the possible configurations is present-

ed hereafter (Table 13).

Table 13: C/I and MON Channel Configuration

Note: A mix of V* and GCI monitoring can be performed for two dis-

tinct channels in the same application.

III.3.5 - CI and Monitor Transmission/Reception

Command

The reception of C/I and Monitor messages are

managed by two interrupt queues.

In transmission, a transmit command register is

implemented for each C/I and monitor channel

(16C/I transmit command registers and 16 Monitor

transmit command registers). Those registers are

accessible in read and write modes by the micro-

processor.

III.4 - Scrambler and Descrambler

The TDM4 and TDM5 can be GCI multipexes.

Each GCI multipex comprises 8 GCI channels.

Each GCI channel comprises two B channels at

64 Kbit/s.

In reception it is possible to switch and to scramble

the contents of 32 B channels of GCI channels to

32 timeslots of the 256 output timeslots. In trans-

mission these 32 timeslots are assigned to 32 B

channels.

In the other direction the contents of an selected B

channels is automatically switched and descram-

bled to one B channel of 16 GCI channel.

See SCR bit of Connection Memory Data Register

CMDR (0E)H.

III.5 - Connection between “ISDN channels”

and GCI channels.

Three timeslots are assigned to one “ISDN chan-

nels”. Each “ISDN channels” comprises three

channels: B1+B2+B* with B*= D1,D2, A, E, S1,

S2, S3, S4 (See figure).

– Upstream. From GCI channels to ISDN chan-

nels.

• in reception: 16 GCI channels (B1+B2+MON+

D+C/I),

MON

S/C

B1, B2 : Bytes of data. Those bytes are not af-

fected by the monitor and CI protocols.

MON

: Monitor channel for operation and

maintenance information.

S/C

: Signalling and control information.

D 2 bits

C/I 4 bits

D 2 bits

C/I 4 bits

C/I 6 bits

CI : The Command/Indicate channel is used for

activation/deactivation of lines and control

functions.

D : These 2 bits carry the 16 kbit/s ISDN basic

access D channel.

C/I validated

or not

CI For analog subscriber (6 bits)

CI For ISDN subscriber (4 bits)

Monitor validated

or not

Monitor V*

Monitor GCI

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