BT8375 CONEXANT [Conexant Systems, Inc], BT8375 Datasheet - Page 166

• 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]

3.8 Receiver Registers
RZCS
RESEED
BSTART
3-48
041—Receive Test Pattern Configuration (RPATT)
RLOFD–RLOFA
—
7
RX Reframe Criteria—Determines the number of frame errors the online framer must detect
before declaring a loss of frame alignment [ALM1; addr 047]. Refer to the Receive Framer
mode in [RFRAME; addr 001]
Alignment) to find which frame bits are monitored.
Receive B8ZS/HDB3 Zero Code Substitution (affects only BPV/LCV/EXZ counting)—When
set, the ZCS decoder does not include bipolar violations received as part of a B8ZS/HDB3
code in the LCV error count [addr 054, 055]. Otherwise, all bipolar violations are counted.
EXZ detection criteria is either 8 or 16 consecutive zeros, depending on the RZCS
configuration.
Re-seed PRBS Sync Detector (auto clear)—If BSTART is active high, writing a one to
RESEED forces the PRBS sync detector to reseed and search for test pattern sync [PSYNC;
addr 00B]. The reseed and search algorithm remains active until a test pattern sync is found.
receiving all 1s will cause false pattern sync. In such cases, check receive slip buffers to see if
not all 1s is being received, then re-enable RESEED.
Enable PRBS Detector and Start Counting PRBS Bit Errors—BERR [addr 058, 059] counting
is enabled when BSTART is active high and a pattern sync is found [PSYNC=1; addr 00B];
otherwise, the BERR counter holds its present value until cleared by a processor read.
—
When inverted data mode is selected, initiating RESEED [RPATT; addr 041] while
6
NOTE:
T1/E1N
RESEED
5
0
0
1
1
1
Other RLOFD–RLOFA combinations are invalid. RAIS and
RLOF status is disabled if RLOFD–RLOFA equal all zeros.
0 = ZCS decoder reports all occurrences of BPV;
also selects EXZ = 16 zeros
1 = ZCS decoder does not report BPVs received as part of ZCS;
also selects EXZ = 8 zeros
0 = no effect
1 = reseed and search for test pattern sync
0 = PRBS detector disabled and BERR stops counting
1 = enable PRBS detector and BERR counter
RLOFD–A
BSTART
0100
1100
0001
0010
0100
4
(Table 2-3, Criteria for Loss/Recovery of Receive Framer
Conexant
FRAMED
3 Consecutive FAS or 915 CRC errors
3
Fully Integrated T1/E1 Framer and Line Interface
3 Consecutive FAS Errors
2 out of 4 F-bit errors
2 out of 5 F-bit errors
2 out of 6 F-bit errors
Reframe Criteria
ZLIMIT
2
RPATT[1]
Bt8370/8375/8376
1
N8370DSE
RPATT[0]
0