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QuadFALC
TM
PEF 22554 E
Functional Description T1/J1
Data Sheet
214
Rev. 1.2, 2006-01-26
The format for receive FS/DL data transmission in time slot 0 of the system interface is as shown in Figure 84 below. In order to get an undisturbed reception even in the asynchronous state bit FMR2.DAIS has to be set.
5.7
Test Functions (T1/J1)
The following chapters describe the test functions which are supported by the QuadFALC
TM.
5.7.1
Pseudo-Random Binary Sequence Generation and Monitor (T1/J1)
The QuadFALC
TM has the ability to generate and monitor pseudo-random binary sequences (PRBS). The
generated PRBS pattern is transmitted to the remote end on pins XL1/2 or XDOP/N and can be inverted optionally.
Generation and monitoring of PRBS pattern is done according to ITU-T O.150 and ITU-T O.151.
The PRBS monitor monitores the PRBS pattern in the incoming data stream. Synchronization is done on the
inverted and non-inverted PRBS pattern. The current synchronization status is reported in status and interrupt
status registers. Enabled by bit LCR1.EPRM each PRBS bit error increments an error counter (CEC2).
Synchronization is reached within 400 ms with a probability of 99.9% at a bit error rate of up to 10
-1.
Different PRBS modes which are using different bits and time slots in a T1/J1 frame can be selected, see
In the “unframed” mode all bits of all slots in a T1/J1 frame are used for PRBS.
In the “framed” mode the frame bit (time slot 0) in a T1/J1 frame is not used for PRBS respectively.
Selection of the PRBS modes “unframed” and “framed” is done by TPC0.PRM = 00
For TPC0.PRM not 00
B, each time slot of an T1/J1 frame can be selected individually to send and receive a PRBS
signal. Selection is done by the registers PRBSTS1 to PRBSTS4. Here the used time slot numbers are the same
as used normally for numbering of the time slots: In T1/J1 frames time slot number 0 (TS0) indicates the frame bit
and the time slot numbers 1 to 24 indicates the payload TS1 to TS24.
If a time slot is used or not for PRBS transmission and reception is controlled by the registers PRBSTS(1:4)
(PRBSTS1_T). The number of used time slots for PRBS is refered to as “N” and is related to the line side. The
range of N is 1, ..., 25 for T1/J1 because of the frame bit (N == 1). The time slot selection 0 up to 24 for T1/J1 by
PBBSTS(1:4) is common for all four ports respectively.
The PRBS time slot selection is independent of the configuration of the system interface, especially independent
of the kind of selected channel translation mode (0 or 1): The time slot numbering for selection of PRBS is the
same as used for the payload data (0, ..., 24), see numbers in the columns “Channels (received time slots)” in
Table 47. TS0 for PRBS selection corresponds to the FS/DL channel. For example PRBS selection of TS16
(PRBSTS3.TS16) is related to time slot 21 at system interface in channel translation mode 0.
The N multiple time slots are selected arbitrarily for PRBS. The PRBS data stream has to be written into or read
from the time slots consecutive respectively.
Note that PRBS deselection of time slot 0 (frame bit) by PRBSTS1.TS0 = 0
B performes a “framed” mode.
For TPC0.PRM unequal 00
B, normally all eight bits of the time slots are used for PRBS (“N × 64 kbit/s”) with
exception of the time slot 0, which includes only the frame bit. To allow CAS-BR in T1/J1 mode, only 7 MSBs of
the all time slots which are selected for PRBS can be optionally used for PRBS to avoid CAS disturbance
(“N
× 56 kbit/s”), the eights bit of all time slots (which is the CAS bit in T1) is not used for PRBS. Setting of this
mode is performed by setting the register bits TPC0.PRM(1:0) to 11
B.
RTR 2.4
TTR 2.4
11
RTR 4.4
TTR 4.4
27
RTR 2.3
TTR 2.3
12
RTR 4.3
TTR 4.3
28
RTR 2.2
TTR 2.2
13
RTR 4.2
TTR 4.2
29
RTR 2.1
TTR 2.1
14
RTR 4.1
TTR 4.1
30
RTR 2.0
TTR 2.0
15
RTR 4.0
TTR 4.0
31
Table 62
Time Slot Assigner HDLC Channel 1 (T1/J1) (cont’d)
Receive Time
Slot Register
Transmit Time
Slot Register
Time Slots
Receive Time
Slot Register
Transmit Time
Slot Register
Time Slots