CN8380 Datasheet, PDF (66/91 Pages) Conexant Systems, Inc – integrated quad line interface unit unit for both 1.544 Mbps (T1) and 2.048 Mbps (E1) applications

3.0 Registers
3.3 Per Channel Registers
CN8380
Quad T1/E1 Line Interface
AIS transmission does not affect transmit data that is looped back to the receiver during
Local Digital Loopback. This allows Local Digital Loopback to be active simultaneously with
the transmission of AIS. If TAIS is activated when RLOOP is enabled, AIS is transmitted using
the jitter-attenuated received clock. Refer to the descriptions of RLOOP and LLOOP below.
Table 3-2 lists transmitter operating modes resulting from various configuration settings and
input conditions.
Table 3-2. Transmitter Operating Modes
Configuration and Input Status
Transmitter Mode
RLOOP
TLOC
0
X
0
X
0
X
0
0
0
1
0
1
1
X
1
X
Note: X is don’t-care.
TAIS
0
1
1
0
0
0
0
1
AUTO_AIS
0
X
X
1
1
1
X
X
AISCLK
X
0
1
X
0
1
X
X
Transmit
Data
Tx Data
AIS
AIS
Tx Data
AIS
AIS
Rx Data
AIS
Transmit
Clock
TCLK
TCLK
TACKI/EACKI
TCLK
TCLK
TACKI/EACKI
RCLK
RCLK
LLOOP
RLOOP
TAIS_PE
Local Analog Loopback—Bipolar data from XTIP/XRING is internally connected to
RTIP/RRING inputs. Externally applied data on RTIP/RRING inputs is ignored.
XTIP/XRING output data is unaffected. Asserting both LLOOP and RLOOP activates Local
Digital Loopback. Refer to the RLOOP description below.
Remote Line Loopback—Dual-rail bipolar data from the receiver (or receive JAT) is internally
connected to the transmitter (or transmit JAT). The recovered clock from the RPLL (or JCLK)
is also looped to provide the transmit clock. Loopback data retains BPV transparency.
Received data is allowed to pass to the RZCS decoder, and digital outputs are unaffected.
Asserting both LLOOP and RLOOP activates LDL. Dual-rail bipolar data from the TZCS
encoder (or transmit jitter attenuator) is internally connected to the RZCS decoder (or receive
jitter attenuator) inputs. The transmit clock, TCLK, is also looped to provide the receive clock,
RCKO. Externally applied data on RTIP/RRING inputs are blocked; however, RLOS and
RALOS detect circuitry continues to operate and report receive signal status. XTIP/XRING
output data is unaffected.
LLOOP
0
0
1
1
RLOOP
0
1
0
1
Loopback
No loopback
Remote Line Loopback
Local Analog Loopback
Local Digital Loopback
TAIS Pin Enable—Allows the use of the TAIS hardware pin instead of the TAIS register bit to
manually transmit AIS.
0 = Use TAIS register bit
1 = Use TAIS pin
3-14
Conexant
N8380DSA
Advance Information
4/21/99