IDT82P20416 Integrated Device Technology, IDT82P20416 Datasheet - Page 39

• Manufacturer Part Number: IDT82P20416
• Description: 16-channel Short Haul T1/e1/j1 Line Interface Unit
• Manufacturer: Integrated Device Technology

3.5.5.2 Pattern Detection
system side may be extracted for pattern detection. The direction of data
extraction is determined by the PD_POS bit (b3, PD,...). One of PRBS or
ARB pattern is selected for detection and IB detection is always active.
data should be decoded by using AMI or B8ZS (for T1/J1) / HDB3 (for
E1). The decoding rule is selected by the R_CODE bit (b2, RCF1,...).
the data should be decoded by using AMI or B8ZS (for T1/J1) / HDB3
(for E1) in Transmit Dual Rail NRZ Format mode and Transmit Dual Rail
RZ Format mode. The decoding rule is selected by the T_CODE bit (b2,
TCF1,...).
Pseudo Random Bit Sequence (PRBS) /Arbitrary Pattern (ARB)
Detection
(b2, PD,...) before PRBS/ARB detection.
desired pattern is re-generated from the extracted data if the desired
pattern is (2^20 - 1) QRSS per O.150-4.5, (2^15 - 1) PRBS per O.152 or
(2^11 - 1) PRBS per O.150; or the desired pattern is programmed in the
ARB[23:0] bits (b7~0, ARBH~ARBM~ARBL,...) if the desired pattern is
ARB. The desired pattern is selected by the PAD_SEL[1:0] bits (b1~0,
PD,...).
Functional Description
IDT82P20416
Data received from the line side or data input from the transmit
If data is extracted from the receive path, before pattern detection the
If data is extracted from the transmit path, before pattern detection
The extracted data can be optionally inverted by the PAD_INV bit
The extracted data is used to compare with the desired pattern. The
In summary, do the followings step by step to detect PRBS/ARB:
• Select the detection direction by the PD_POS bit (b3, PD,...);
• Set the ARB[23:0] bits (b7~0, ARBH~ARBM~ARBL,...) if the ARB
• Select the desired PRBS/ARB pattern by the PAD_SEL[1:0] bits
pattern is desired - this step is omitted if the PRBS pattern is
desired;
(b1~0, PD,...).
39
16-CHANNEL SHORT HAUL T1/E1/J1 LINE INTERFACE UNIT
programming and pattern comparison is shown in Figure-21.
ated PRBS pattern or the programmed ARB pattern for more than 64-bit
hopping window, the pattern is synchronized and the PA_S bit (b5,
STAT1,...) will be set.
detected in a 64-bit hopping window, the pattern is out of synchroniza-
tion and the PA_S bit (b5, STAT1,...) will be cleared.
ARB error. When a PRBS/ARB error is detected during the synchroniza-
tion, the ERR_IS bit (b1, INTS2,...) will be set and an interrupt will be
reported by INT if not masked by the ERR_IM bit (b1, INTM2,...). The
PRBS/ARB error may be counted by an internal Error Counter. Refer to
Section 3.5.6 Error Counter.
sition (from ‘0’ to ‘1’ or from ‘1’ to ‘0’) on the PA_S bit (b5, STAT1,...) will
set the PA_IS bit (b5, INTS1,...) to ‘1’, as selected by the PA_IES bit (b5,
INTES,...). When the PA_IS bit (b5, INTS1,...) is ‘1’, an interrupt will be
reported by INT if not masked by the PA_IM bit (b5, INTM1,...).
from Rx path
or Tx path
The priority of decoding, data inversion, pattern re-generation, bit
During comparison, if the extracted data coincides with the re-gener-
In synchronization state, if more than 6 PRBS/ARB errors are
In synchronization state, each mismatched bit will generate a PRBS/
A transition from ‘0’ to ‘1’ on the PA_S bit (b5, STAT1,...) or any tran-
Figure-21 PRBS / ARB Detection
Decoding
Inversion
Data
Programming
Generation
PRBS Re-
ARB[23:0]
December 17, 2009
Comparison