
Data Sheet
143
Rev. 1.0, 2005-06-02
OctalLIUTM
PEF 22508 E
Register DescriptionLine Status Register 1
Line Status Register 1
LSR1
Offset
Reset Value
Line Status Register 1
xx4DH
xxH
Field
Bits
Type
Description
EXZD
7
r
Excessive Zeros Detected
Significant only, if excessive zero detection has been enabled
(MR0.EXZE = 1). Set after detection of more than 3 (HDB3 code) or 15
(AMI code) contiguous zeros in the received data stream.This bit is
cleared on read.
PDEN
6
r
Pulse-Density Violation Detected
The pulse-density of the received data stream is below the requirement
defined by ANSI T1. 403 or more than 14 consecutive zeros are detected.
With the violation of the pulse-density this bit is set and remains active
until the pulse-density requirement is fulfilled for 23 consecutive "1"-
pulses. Additionally an interrupt status ISR0.PDEN is generated with the
rising edge of PDEN.
LLBDD
4
r
Line Loop-Back Deactivation Signal Detected, only valid in T1 mode
In E1 mode the equivalent bit is LSR2.LLBDD.
This bit is set in case of the LLB deactivate signal is detected and then
received over a period of more than 33,16 ms with a bit error rate less
than 10-2. The bit remains set as long as the bit error rate does not exceed
10-2. If framing is aligned, the first bit position of any frame is not taken
into account for the error rate calculation.Any change of this bit causes an
LLBSC interrupt.
LLBAD
3
r
Line Loop-Back Activation Signal Detected, only valid in T1 mode
In E1 mode the equivalent bit is LSR2.LLBAD.
Depending on bit LCR1.EPRM the source of this status bit changed.
LCR1.EPRM = 0: This bit is set in case of the LLB activate signal is
detected and then received over a period of more than 33,16 ms with
a bit error rate less than 10-2. The bit remains set as long as the bit
error rate does not exceed 10-2. If framing is aligned, the first bit
position of any frame is not taken into account for the error rate
calculation. Any change of this bit causes an LLBSC interrupt.
LCR1.EPRM = 1: The current status of the PRBS synchronizer is
indicated in this bit. It is set high if the synchronous state is reached
even in the presence of a bit error rate of up to 10-3. A data stream
containing all zeros or all ones with/without framing bits is also a valid
pseudo-random binary sequence.