Rainbow Electronics DS26504 - Manual (Page 48)

DS26504 T1/E1/J1/64KCC BITS Element
48 of 128
9.2 E1 Information Registers
Register Name: INFO2
Register Description: Information Register 2
Register Address: 12h
Bit
# 7 6 5 4 3 2 1 0
Name — — — — — CRCRC FASRC CASRC
Default 0 0 0 0 0 0 0 0
HW
Mode
X X X X X X X X
Bit 0: CAS Resync Criterion Met Event (CASRC). Set when two consecutive CAS MF alignment words are received in
error.
Bit 1: FAS Resync Criterion Met Event (FASRC). Set when three consecutive FAS words are received in error.
Bit 2: CRC Resync Criterion Met Event (CRCRC). Set when 915/1000 codewords are received in error.
Bits 3 to 7: Unused
Register Name:
INFO3
Register Description: Information Register 3 (Real Time)
Register Address: 1Ch
Bit
# 7 6 5 4 3 2 1 0
Name CSC5 CSC4 CSC3 CSC2 CSC0 FASSA CASSA CRC4SA
Default 0 0 0 0 0 0 0 0
HW
Mode
X X X X X X X X
Bit 0: CRC4 MF Sync Active (CRC4SA). Set while the synchronizer is searching for the CRC4 MF alignment word.
Bit 1: CAS MF Sync Active (CASSA). Set while the synchronizer is searching for the CAS MF alignment word.
Bit 2: FAS Sync Active (FASSA). Set while the synchronizer is searching for alignment at the FAS level.
Bits 3 to 7: CRC4 Sync Counter Bits (CSC0, CSC2 to CSC5). The CRC4 sync counter increments each time the 8ms-CRC4
multiframe search times out. The counter is cleared when the framer has successfully obtained synchronization at the CRC4
level. The counter can also be cleared by disabling the CRC4 mode (E1RCR.3 = 0). This counter is useful for determining the
amount of time the framer has been searching for synchronization at the CRC4 level. ITU G.706 suggests that if
synchronization at the CRC4 level cannot be obtained within 400ms, then the search should be abandoned and proper action
taken. The CRC4 sync counter will roll over. CSC0 is the LSB of the 6-bit counter. (Note: The second LSB, CSC1, is not
accessible. CSC1 is omitted to allow resolution to >400ms using 5 bits.)