PEB22554 SIEMENS [Siemens Semiconductor Group], PEB22554 Datasheet - Page 250

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

Figure 64 gives an overview of influences on synchronization status for the case of
different external actions. Activation of auto-mode and non-auto mode is performed via
bit FMR4.AUTO. Generally, for initiating resynchronization it is recommended to use bit:
FMR0.EXLS first. In case where the synchronizer remains in the asynchronous state, bit
FMR0.FRS may be used to enforce it to lock onto the next framing candidate, although
it might be a simulated one.
7.7.1
The allocation of the FT bits (bit 1 of frames 1 and 3) for frame alignment signal is shown
in table 22.
The FS bit may be used for signaling.
Remote alarm (yellow alarm) is indicated by setting bit 2 to ‘0’ in each time-slot.
Table 22
4-Frame Multiframe Structure
Frame Number
1
2
3
4
Synchronization Procedure
For multiframe synchronization, the terminal framing bits (FT bits) are observed. The
synchronous state is reached if at least one terminal framing candidate is definitely
found, or the synchronizer is forced to lock onto the next available candidate
(FMR0.FRS).
7.7.2
Normally, this kind of multiframe structure only makes sense when using the
CAS Robbed Bit Signaling. The multiframe alignment signal is located at the FS-bit
position of every other frame (refer to table 23).
There are two possibilities of remote alarm (yellow alarm) indication:
• Bit 2 = 0 in each time-slot of a frame, selected with bit FMR0.SRAF = 0
• The last bit of the multiframe alignment signal (bit 1 of frame 12) changes from ‘0’ to
Synchronization Procedure
In the synchronous state terminal framing (FT bits) and multiframing (FS bits) are
observed, independently. Further reaction on framing errors depends on the selected
sync/resync procedure (via bit FMR2.SSP):
Semiconductor Group
‘1’, selected with bit FMR0.SRAF = 1.
4-Frame Multiframe
12-Frame Multiframe (D4 or SF Format)
F
1
–
0
–
T
250
Functional Description T1 / J1
F
Service bit
Service bit
S
PEB 22554
09.98