stlc5464 STMicroelectronics, stlc5464 Datasheet - Page 27

• Manufacturer Part Number: stlc5464
• Description: Multi-hdlcwith Switching Matrix Associated
• Manufacturer: STMicroelectronics

III - FUNCTIONAL DESCRIPTION (continued)
III.3.2 - GCI and V* Protocol
A TDM can carry 8 GCI channels or V* channels. The monitor and S/C bytes always stand at the same
position in the TDM in both cases.
The GCI or V* channels are composed of 4 bytes
and have both the same general structure.
B1, B2 : Bytes of data. Those bytes are not
MON
S/C
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
CI : The Command/Indicate channel is used for
D : These 2 bits carry the 16 kbit/s ISDN basic
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.
In V* protocol, there isn’t any handshakemode.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 (is-
sue1.0, march 1989) and the France Telecom
Specification about ISDN Basic Access second
generation (November 1990).
TS0
B1
B1
activation/deactivation of lines and control
functions.
access D channel.
D
D
: Monitor channel for operation and
: Signalling and control information.
affected by the monitor and CI protocols.
maintenance information.
CGI Channel 0
TS1
B2
C/I 6 bits
B2
MON
TS2
C/I 4 bits
C/I 4 bits
TS3
S/C
MON
CGI Channel 1 to Channel 6
A
A
T
S/C
E
E
E
III.3.3 - Structure of the Treatment
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 the HDLC receiver. The
Monitor and S/C bytes are multiplexed and sent to
the CI and Monitor receivers (see Figure 11 on
Page 28).
In transmission, the S/C and Monitor bytes are
recombined by multiplexing the information pro-
vided by the Monitor,C/I and the HDLCTransmitter.
Like in reception,the D channelis switched through
the matrix.
III.3.4 - CI and Monitor Channel Configuration
Monitor channel data is located in a time slot ; the
CI and monitor handshakebits are in the next time
slot.
Each channel can be defined independently. A
table with all the possible configurations is pre-
sented hereafter (Table 13).
Table 13 : C/I and MON Channel Configuration
Note : A mix of V* and GCI monitoring can be performed for two
distinct channels in the same application.
III.3.5 - CI and Monitor Transmission/Reception
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 (16
C/I transmit command registers and 16 Monitor
transmit command registers). Those registers are
accessible in read and write modes by the micro-
processor.
C/I validated or not
Monitor validated
or not
Command
TS28
B1
CI For analog subscriber (6 bits)
CI For ISDN subscriber (4 bits)
CGI Channel 7
TS29
B2
Monitor GCI
Monitor V*
TS30
MON
STLC5464
TS31
S/C
27/83