BT8375 CONEXANT [Conexant Systems, Inc], BT8375 Datasheet - Page 78

• 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]

2.0 Circuit Description
2.7 Transmit System Bus
2.7.4 Transmit Framing
Figure 2-27. Transmit Framing and Timebase Alignment Options
2-50
NOTE(S):
1. EMBED located in SBI_CR (addr 0D0).
2. TSB_ALIGN and TX_ALIGN located in TSB_CR (addr 0D4).
3. EMBED = 0 is only applicable if TPCMI is operating at the line rate.
TMSYNCO
TFSYNCO
TMSYNCI
TFSYNCI
TPCMI
Offset
TSB
FSYNC MSYNC
TSB Timebase
A TSB Aligns to TPCMI (EMBED = 0)
B TSB Aligns to TX (TSB_ALIGN = 1)
The transmit data stream has two framing functions: offline framer and an online
framer.
transmit frame alignment (TFSYNC). The online framer monitors the frame
alignment found by the offline framer and recovers multiframe alignment
(TMSYNC).
of Frame (TLOF) status bit in Alarm 2 status [ALM2; addr 048] register by the
online framer. The TLOF criteria is set in the TLOFA, TLOFB, and TLOFC bits
of the Transmitter Configuration register [TCR1; addr 071]. The online framer
supports the following LOF criteria for T1: 2 frame bit errors out of 4; 2 out of 5;
or 2 out of 6. For E1, it supports 3 out of 3.
for a new frame alignment, provided transmit framing is enabled [TABORT; addr
071]. If embedded framing is enabled [EMBED; addr 0D0], the offline framer
examines the TSLIP buffer output, TNRZ, for transmit frame alignment. If
embedded framing is disabled, the offline framer examines the slip buffer input
(TPCMI) for transmit frame alignment. This case (EMBED = 0) is only applicable
if TPCMI is configured to operate at the line rate: 2,048 kbps E1, or 1,544 kbps
T1. If transmit framing is disabled, the offline framer waits for a reframe command
[TFORCE; addr 071] before beginning frame alignment search.
Transmit frame resynchronization is initiated by activating the Transmit Loss
When TLOF is asserted, the offline framer searches the transmit data stream
Figure 2-27
B
A
Conexant
illustrates these functions. The offline framer recovers the
(EMBED = 1)
Framer
TSLIP
Buffer
Offline
Pass
Pass
0 1
MF
MF
C
D
Fully Integrated T1/E1 Framer and Line Interface
TPHASE
(TUSLIP)
Recenter
FSYNC
C TX Aligns to TNRZ (EMBED = 1)
D TX Aligns to TSB (TX_ALIGN = 1)
FAS
TX Timebase
Online
CAS
CAS
Bt8370/8375/8376
MSYNC
Online
MFAS
N8370DSE
TNRZ