PEB22554 SIEMENS [Siemens Semiconductor Group], PEB22554 Datasheet - Page 74

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

Figure 24
CRC4 Multiframe Alignment Recovery Algorithms
Semiconductor Group
Assume CRC-4 to CRC-4 Interworking:
Confirm Primary BFA Associated with CRC-4 MFA
Adjust Primary BFA if Necessary
Reset Internal Multiframe Alignment Status
(FRS0.LMFA = 0)
Yes
Start CRC-4 Performance Monitoring
Error Count
or LFA ?
OUT of Primary BFA:
IN Primary BFA:
CRC-4
Inhibit Incoming CRC-4 Performance Monitoring
Reset all Timers
Set FRS0.LFA/LMFA/NMF = 110
Start 400 ms Timer
Enable Primary BFA Loss Checking Process
Reset Internal Frame Alignment Status
(FRS0.LFA = 0)
Yes
_
< 915
No
CRC-4 MFA Search
Start 8 ms Timer
No
BFA Search ?
MFA be found
Can CRC-4
in 8 ms ?
Primary
Yes
74
No
Assume CRC-4 to non CRC-4 Interworking:
Confirm Primary BFA
Set Internal 400 ms Timer Expiration Status Bit
(FRS0.NMF = 1)
Continue CRC-4 Performance Monitoring
No
(BFA = Basic Frame Alignment)
Functional Description E1
BFA Search
Elapsed ?
Parallel
Good ?
400 ms
Timer
Yes
No
Yes
PEB 22554
ITD10310
09.98