Rainbow Electronics DS2153Q - Manual (Page 18)

DS2153Q
022697 18/48
IMR2: INTERRUPT MASK REGISTER 2 (Address=17 Hex)
(MSB) (LSB)
RMF RAF TMF SEC TAF LOTC RCMF TSLIP
SYMBOL POSITION NAME AND DESCRIPTION
RMF IMR2.7 Receive CAS Multiframe.
0=interrupt masked
1=interrupt enabled
RAF IMR2.6 Receive Align Frame.
0=interrupt masked
1=interrupt enabled
TMF IMR2.5 Transmit Multiframe.
0=interrupt masked
1=interrupt enabled
SEC IMR2.4 One Second Timer.
0=interrupt masked
1=interrupt enabled
TAF IMR2.3 Transmit Align Frame.
0=interrupt masked
1=interrupt enabled
LOTC IMR2.2 Loss Of Transmit Clock.
0=interrupt masked
1=interrupt enabled
RCMF IMR2.1 Receive CRC4 Multiframe.
0=interrupt masked
1=interrupt enabled
TSLIP IMR2.0 Transmit Side Elastic Store Slip.
0 = interrupt masked
1 = interrupt enabled
5.0 ERROR COUNT REGISTERS
There are a set of four counters in the DS2153Q that
record bipolar or code violations, errors in the CRC4
SMF code words, E
bits as reported by the far end, and word errors in the
FAS. Each of these four counters are automatically
updated on either one second boundaries (CCR2.7=0)
or every 62.5 ms (CCR2.7=1) as determined by the
timer in Status Register 2 (SR2.4). Hence, these regis-
ters contain performance data from either the previous
second or the previous 62.5 ms. The user can use the
interrupt from the timer to determine when to read these
registers. The user has a full second
(or 62.5 ms) to read the counters before the data is lost.
5.1 BPV or Code Violation Counter
Violation Count Register 1 (VCR1) is the most signifi-
cant word and VCR2 is the least significant word of a
16–bit counter that records either BiPolar Violations
(BPVs) or Code Violations (CVs). If CCR2.6=0, then the
VCR counts bipolar violations. Bipolar violations are
defined as consecutive marks of the same polarity. In
this mode, if the HDB3 mode is set for the receive side
via CCR1.2, then HDB3 code words are not counted as
BPVs. If CCR2.6=1, then the VCR counts code viola-
tions as defined in CCITT O.161. Code violations are
defined as consecutive bipolar violations of the same
polarity. In most applications, the DS2153Q should be
programmed to count BPVs when receiving AMI code
and to count CVs when receiving HDB3 code. This
counter increments at all times and is not disabled by
loss of sync conditions. The counter saturates at 65,535
and will not rollover. The bit error rate on a E1 line would
have to be greater than 10**–2 before the VCR would
saturate.