3.0 Circuit Descriptions
RS8953B/8953SPB
3.5 HDSL Channel
HDSL Channel Unit
After detecting a sync word and changing to the Sync Acquired state, the
framer progresses through a programmable number of intermediate “Sync
Acquired” states before entering the In Sync state. In each “Sync Acquired” state,
the framer searches for the previously detected sync word value in one of two
locations based upon the absence or presence of the 4 STUFF bits. If the sync
word is detected in one of the two possible locations, the STATE_CNT counter is
incremented [STATUS_2; addr 0x06]. When STATE_CNT increments to the
value selected by the REACH_SYNC criteria [RCMD_1; addr 0x60], the framer
changes to the In Sync state. During the Sync Acquired state, if valid sync is not
detected at one of the two possible locations, the framer returns to the Out Of
Sync state, as shown in Figure 3-23.
Figure 3-23. HDSL Receive Framer Synchronization
Consecutive SYNC_ACQUIRED States per REACH_SYNC Criteria
1
2
3
4
5
6
7
8
SYNC
SYNC
No SYNC
SYNC
OUT_OF
SYNC
IN_SYNC
No SYNC
SYNC
No SYNC
No SYNC
8
7
6
5
4
3
2
1
Consecutive SYNC_ERRORED States per LOSS_SYNC Criteria
3-30
Conexant
N8953BDSB
CONEXANT [ CONEXANT SYSTEMS, INC ]
