DS21354/DS21554 3.3V/5V E1 Single-Chip Transceivers
Figure 18-14. DS21354/DS21554 Framer Synchronization Flowchart
Power Up
RLOS = 1
FAS Search
FASSA = 1
RLOS = 1
FAS Sync
Criteria Met
FASSA = 0
Resync if
RCR1.1 = 0
Increment CRC4
Sync Counter;
CRC4SA = 0
8ms
Time
Out
CRC4 Multiframe Search
(if enabled via CCR1.0)
CRC4SA = 1
CAS Multiframe Search
(if enabled via CCR1.3)
CASSA = 1
CAS Sync
Criteria Met
CASSA = 0
CRC4 Sync Criteria
Met; CRC4SA = 0;
Reset CRC4
Sync Declared
RLOS = 0
Sync Counter
Set FASRC
(RIR.1)
Check for FAS
Framing Error
FAS Resync
Criteria Met
(depends on RCR1.2)
Check for >=915
Out of 1000
If CRC4 is on
(CCR1.0 = 1)
CRC4 Resync
Criteria Met
(RIR.2)
CRC4 Word Errors
CAS Resync
Criteria Met;
Set CASRC
(RIR.0)
If CAS is on
Check for CAS
MF Word Error
(CCR1.3 = 0)
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MAXIM [ MAXIM INTEGRATED PRODUCTS ]
