2.0 Circuit Description
2.4.3 Error Counters
The following Performance Monitoring (PM) counters are available in the
RCVR: Framing Bit Errors (FERR), CRC Errors (CERR), Line Code Violations
(LCV), and Far End Block Errors (FEBE). All PM count registers are reset on
read unless LATCH_CNT is set in the Alarm/Error/Counter Latch Configuration
register [LATCH; addr 046]. LATCH_CNT enables the 1-second latching of
counts coincident with the 1-second timer interrupt [ISR6; addr 005]. One-second
latching of PM counts is required if AUTO_PRM responses are enabled. All PM
counters can be disabled during RLOF, RLOS, and RAIS, using the STOP_CNT
bit in the LATCH register.
18.104.22.168 Frame Bit Error
The 12-bit Framing Bit Error Counter [FERR; addr 050 and 051] increments each
time a receive Ft, Fs, T1DM, FPS, or FAS error is detected. Fs (T1) and NFAS
(E1) errors can be included in the FERR count by setting FS_NFAS in Receive
Alarm Signal Configuration [RALM; addr 045]. An interrupt is available to
indicate that the FERR counter overflowed in the Counter Overflow Interrupt
Status register [ISR4; addr 007].
22.214.171.124 CRC Error
The 10-bit Cyclic Redundancy Check Error Counter [CERR; addr 052 and 053]
increments each time a receive CRC4 (E1) or CRC6 (T1) error is detected. An
interrupt is available to indicate that the CERR counter overflowed in ISR4.
126.96.36.199 LCV Error
The 16-bit Line Code Violation Error Counter [LCV; addr 054 and 055]
increments each time a receive Bipolar Violation (BPV)—not including line
coding—is detected. The LCV count can include EXZ if EXZ_LCV in the
Receive Alarm Signal Configuration register [RALM; addr 045] is set. EXZ can
be configured [RZCS; addr 040] to be 8 or 16 successive 0s, following a 1. An
interrupt is available to indicate that the LCV counter overflowed in ISR4.
188.8.131.52 FEBE Counter
The 10-bit Far End Block Error (FEBE) counter [FEBE; addr 056 and 057]
increments each time the RCVR encounters an E1 far-end block error. An
interrupt is available to indicate that the FEBE counter overflowed in ISR4.
Fully Integrated T1/E1 Framer and Line Interface
If STOP_CNT is negated, error monitoring during RLOF conditions will
detect FERR, CERR, and FEBE according to the last known frame