PEB22554 SIEMENS [Siemens Semiconductor Group], PEB22554 Datasheet - Page 48

• Manufacturer Part Number: PEB22554
• Description: ICs for Communications
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

PEB 22554
Functional Description E1
in the last 4 bits per time-slot and are aligned to the data on RDO. The first 4 bits per
time-slot could be optionally fixed high or low, except time-slot 0 and 16. In time-slot
0 the FAS / NFAS word is transmitted, in time-slot 16 the CAS multiframe pattern. Data
on RSIG are only valid if the freeze signaling status is inactive. With FMR1.SAIS an all
ones may be transmitted on RDO and RSIG.
The signaling procedure will be done as it is described in ITU-T G.704 and G.732.
The main functions are:
- Synchronization to a CAS multiframe
- Detection of AIS and Remote Alarm in CAS multiframes
- Separation of CAS Service bits X1-X3
- Storing of received signaling data in registers RS1-16 with last look capability
Updating of the received signaling information is controlled by the freeze signaling
status. The freeze signaling status is automatically activated if a Loss of Signal, or a
Loss of CAS Multiframe Alignment or a receive slip occurs. The current freeze status
is output on port FREEZ (RPA-D) and indicated by register SIS.SFS. If SIS.SFS is
active updating of the registers 1-16 is disabled. Optionally automatic freeze signaling
may be disabled by setting bit SIC3.DAF.
To relieve the µP load from always reading the complete RS1-16 buffer every 2 msec
the QuadFALC notifies the µP via interrupt ISR0.CASC only when signaling changes
from one multiframe to the next. Additionally the QuadFALC generates a receive
signaling data change pointer (RSP1/2) which directly points to the updated RS1-16
register .
Semiconductor Group
48
09.98