DS21354/DS21554 3.3V/5V E1 Single-Chip Transceivers
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7.2.
CRC4 Error Counter
CRC4 Count Register 1 (CRCCR1) is the most significant word and CRCCR2 is the least significant
word of a 10-bit counter that records word errors in the Cyclic Redundancy Check 4 (CRC4). Since the
maximum CRC4 count in a one second period is 1000, this counter cannot saturate. The counter is
disabled during loss of sync at either the FAS or CRC4 level; it will continue to count if loss of
multiframe sync occurs at the CAS level.
CRCCR1: CRC4 COUNT REGISTER 1 (Address = 02 Hex)
CRCCR2: CRC4 COUNT REGISTER 2 (Address = 03 Hex)
(MSB)
(LSB)
(See Note)
(See Note)
(See Note)
(See Note)
(See Note)
(See Note)
CRC9 CRC8 CRCCR1
CRC7 CRC6 CRC5 CRC4 CRC3 CRC2 CRC1 CRC0 CRCCR2
SYMBOL
POSITION
NAME AND DESCRIPTION
CRC9 CRCCR1.1
MSB of the 10-Bit CRC4 error count
CRC0 CRCCR2.0
LSB of the 10-Bit CRC4 error count
Note: The upper six bits of CRCCR1 at address 02 are the most significant bits of the 12-bit FAS error counter.
7.3.
E-Bit Counter
E–bit Count Register 1 (EBCR1) is the most significant word and EBCR2 is the least significant word of
a 10–bit counter that records Far-End Block Errors (FEBE) as reported in the first bit of frames 13 and 15
on E1 lines running with CRC4 multiframe. These count registers will increment once each time the
received E-bit is set to zero. Since the maximum E-bit count in a one second period is 1000, this counter
cannot saturate. The counter is disabled during loss of sync at either the FAS or CRC4 level; it will
continue to count if loss of multiframe sync occurs at the CAS level.
EBCR1: E-BIT COUNT REGISTER 1 (Address = 04 Hex)
EBCR2: E-BIT COUNT REGISTER 2 (Address = 05 Hex)
(MSB)
(LSB)
(See Note)
(See Note) (See Note)
(See Note)
(See Note) (See Note)
EB9 EB8
EBCR1
EB7 EB6 EB5 EB4 EB3 EB2 EB1 EB0
EBCR2
SYMBOL
POSITION
NAME AND DESCRIPTION
EB9 EBCR1.1
MSB of the 10-Bit E-Bit Error Count
EB0 EBCR2.0
LSB of the 10-Bit E-Bit Error Count
Note: The upper six bits of EBCR1 at address 04 are the least significant bits of the 12-bit FAS error counter.