ds21ft40 Maxim Integrated Products, Inc., ds21ft40 Datasheet - Page 39

• Manufacturer Part Number: ds21ft40
• Description: Ds21ft40 Four X Three 12 Channel E1 Framer
• Manufacturer: Maxim Integrated Products, Inc.

IMR2: INTERRUPT MASK REGISTER 2 (Address=17 Hex)
7. ERROR COUNT REGISTERS
There are a set of four counters in each framer 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 registers contain
performance data from either the previous second or the previous 62.5 ms. The user can use the interrupt
from the one second 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. All four counters will saturate at their respective
maximum counts and they will not rollover.
BPV or Code Violation Counter
Violation Count Register 1 (VCR1) is the most significant 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 violations as defined in ITU O.161.
Code violations are defined as consecutive bipolar violations of the same polarity. In most applications,
(MSB)
RMF
SYMBOLS
RCMF
LOTC
TSLIP
RMF
TMF
RAF
SEC
TAF
RAF
POSITION
IMR2.7
IMR2.6
IMR2.5
IMR2.4
IMR2.3
IMR2.2
IMR2.1
IMR2.0
TMF
NAME AND DESCRIPTION
Receive CAS Multiframe.
Receive Align Frame.
One Second Timer.
Receive CRC4 Multiframe.
0=interrupt masked
1=interrupt enabled
0=interrupt masked
1=interrupt enabled
Transmit Multiframe.
0=interrupt masked
1=interrupt enabled
0=interrupt masked
1=interrupt enabled
Transmit Align Frame.
0=interrupt masked
1=interrupt enabled
Loss Of Transmit Clock.
0=interrupt masked
1=interrupt enabled
0=interrupt masked
1=interrupt enabled
Transmit Side Elastic Store Slip Occurrence.
0=interrupt masked
1=interrupt enabled
SEC
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TAF
LOTC
RCMF
TSLIP
(LSB)
DS21FT40