Rainbow Electronics DS2141A - Manual (Page 15)

DS2141A
021997 15/35
5.0 ERROR COUNT REGISTERS
There is a set of three counters in the DS2141A that re-
cord bipolar violations, errors in the CRC6 code words,
and frame bit errors. Each of these three counters is au-
tomatically updated on one–second boundaries as de-
termined by the one–second timer in Status Register 2
(SR2.5). Hence, these registers contain performance
data from the previous second. The user can use the
interrupt from the one–second timer to determine when
to read these registers. The user has a full second to
read the counters before the data is lost.
BPVCR1: BIPOLAR VIOLATION COUNT REGISTER 1 (23h)
BPVCR2: BIPOLAR VIOLATION COUNT REGISTER 2 (24h)
(MSB) (LSB)
BV15 BV14 BV13 BV12 BV11 BV10 BV9 BV8
BV7 BV6 BV5 BV4 BV3 BV2 BV1 BV0
SYMBOL POSITION NAME AND DESCRIPTION
BV15 BPVCR1.7 MSB of the bipolar violation count.
BV0 BPVCR2.0 LSB of the bipolar violation count.
Bipolar Violation Count Register 1 (BPVCR1) is the
most significant word and BPVCR2 is the least signifi-
cant word of a 16–bit counter that records bipolar viola-
tions (BPVs). If the B8ZS mode is set for the receive
side via CCR2.2, then B8ZS code words are not
counted. This counter increments at all times and is not disabled by loss of sync conditions. The counter satu-
rates at 65,535 and will not roll over. If the DS2141A is
programmed to record ESF error events (RCR2.0=1),
then the BPVCR will increment for each ESF multiframe
that contains either an error in the CRC6 word or an out–
of–frame occurrence (loss of sync).
CRCCR1: CRC6 COUNT REGISTER 1 (25h)
CRCCR2: CRC6 COUNT REGISTER 2 (26h)
(MSB) (LSB)
CRC7 CRC6 CRC5 CRC4 CRC3 CRC2 CRC1 CRC0
CRC7 CRC6 CRC5 CRC4 CRC3 CRC2 CRC1 CRC0
SYMBOL POSITION NAME AND DESCRIPTION
CRC7 CRCCR1.7 MSB of the CRC6 count.
CRC0 CRCCR2.0 LSB of the CRC6 count.
CRC6 Count Register 1 (CRCCR1) is the most signifi-
cant word and CRCCR2 is the least significant word of a
16–bit counter that records word errors in the Cyclic Re-
dundancy Check 6 (CRC6) when the DS2141A is oper- ated in the ESF framing mode (CCR2.3 = 1). This count-
er saturates at 65,535 and will not roll over. The counter
is disabled during loss of sync conditions.
BPVCR1
BPVCR2
CRCCR1
CRCCR2