BT8375 CONEXANT [Conexant Systems, Inc], BT8375 Datasheet - Page 248

• Manufacturer Part Number: BT8375
• Description: single chip transceivers for T1/E1 and Integrated Service Digital Network (ISDN) primary rate interfaces
• Manufacturer: CONEXANT [Conexant Systems, Inc]

3.17 System Bus Registers
TLOOP
Table 3-23. Remote DS0 Channel Loopback
TIDLE
TLOCAL
TSIGA–TSIGD
3-130
NOTE(S):
TLOOP
0
0
0
0
0
0
0
0
1
1
1
1
If RX Signaling, RSIGn output buffer supplies transmit signaling.
TIDLE
X
X
X
X
0
0
0
0
1
1
1
1
Remote DS0 Channel Loopback—Transmits data supplied from RSLIP buffer contents.
TLOOP works in conjunction with other TPCn control bits to select the source of transmitted
data and signaling (see
Transmit Idle—Transmit data supplied from TSLIP_LO buffer contents. The processor writes
an 8-bit idle pattern to TSLIP_LO for output on the selected time slot, or optionally writes
real-time data output to TSLIP_LO after each TFRAME interrupt [ISR3; addr 008]. Only
TSLIP_HI buffer is updated from TPCMI to allow continued local DS0 channel loopback.
Transmit Local Signaling—When active, TLOCAL transmits TSIGA–TSIGD values in output
ABCD signaling bits.
In E1, when it is attempted to merge signaling embedded in the TPCMI datastream with
signaling inserting by TLOCAL [TPCn; addr 100-11F], the signaling inserted by TLOCAL
appears two time slots early with TX_ALIGN bit set in [TSB_CR; addr 0D4]. Therefore,
signaling intended for TS1 would instead be inserted into TS31. TX_ALIGN needs to be set.
This offset does not occur during local signaling insertion for all 32 time slots. In T1,
transmitting local signaling should be synchronized with Transmit Multiframe interrupt
[TMF_IER3; addr 010]. This would avoid transmitting intermediate values.
Transmit Local Signaling—Holds the 4-bit ABCD signaling value, which is output when
TLOCAL is active. In AB only applications, such as T1/SF framing, TSIGC and TSIGD must
also be written with the same data as TSIGA and TSIGB. In E1 modes, TS0 and TS16 local
signaling value determines CAS multiframe alignment signal (MAS) and XYXX output.
TLOCAL
0
0
0
1
0
0
0
1
0
0
0
1
TSIGO
X
X
X
0
0
1
0
0
1
0
0
1
0 = normal data output
1 = transmit idle data output
0 = TSIGO or RSIGO control output signaling
1 = transmit signaling from TSIGA–TSIGD
Table
RSIGO
3-23).
X
X
X
0
1
0
0
1
0
0
1
0
Conexant
Sig Source
TSIGA–D
TSIGA–D
TSIGA–D
RSIGn
RSIGn
RSIGn
TSIGn
TSIGn
TSIGn
None
None
None
Fully Integrated T1/E1 Framer and Line Interface
Data Source
TSLIP_LO
TSLIP_LO
TSLIP_LO
TSLIP_LO
RXDATA
RXDATA
RXDATA
RXDATA
TPCMI
TPCMI
TPCMI
TPCMI
Clear Channel
Rx Signaling
Tx Signaling
Local Signaling
Idle Code
Idle Code Rx Signaling
Idle Code Tx Signaling
Idle Code Local Signaling
Remote Loop
Remote Loop Rx Signaling
Remote Loop Tx Signaling
Remote Loop Local Signaling
Bt8370/8375/8376
Channel Mode
N8370DSE