DS21FT40 datasheet(39/87 Pages) DALLAS

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DS21FT40

39 of 87

IMR2: INTERRUPT MASK REGISTER 2 (Address=17 Hex)

(MSB)

(LSB)

RMF

RAF

TMF

SEC

TAF

LOTC

RCMF

TSLIP

SYMBOLS

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 Occurrence.

0=interrupt masked

1=interrupt enabled

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,

DS21FT40 Datasheet(PDF) 39 Page - Dallas Semiconductor

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