XRT7250 datasheet(33/463 Pages) EXAR

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XRT7250

DS3/E3 FRAMER IC

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REV. 1.1.1

ExtLOS

Receive LOS (Loss of Signal) Indicator Input (from XRT7300 LIU

IC).

This input pin is intended to be connected to the RLOS (Receive Loss of Sig-

nal) output pin of the XRT7300 Line Interface Unit IC. The user can monitor the

state of this pin by reading the state of Bit 0 (RLOS) within the Line Interface

Scan Register (Address = 0x81).

If this input pin is "low", then it means that the XRT7300 device is currently

NOT declaring an "LOS (Loss of Signal) condition. However, if this input pin is

"high", then it means that the XRT7300 device is currently declaring an LOS

(Loss of Signal) condition.

For more information on the operation of the XR-T7300 DS3/E3 Line Receiver

IC, please consult the "XRT7300 DS3/STS-1/E3 Line Interface Unit IC" data

sheet.

Asserting the RLOS input pin will cause the XRT7250 DS3/E3 Framer device

to declare an "LOS (Loss of Signal) condition. Therefore, this input pin should

not be used as a general purpose input.

DMO

"Drive Monitor Output" Input (from the XR-T7300 DS3/E3 Line

Interface Unit IC).

This input pin is intended to be tied to the DMO output pin of the XRT7300

DS3/E3 Line Interface Unit IC. The user can determine the state of this input

pin by reading Bit 2 (DMO) within the Line Interface Scan Register (Address =

0x81). If this input signal is "high", then it means that the drive monitor circuitry

(within the XRT7300 DS3/E3 Line Interface Unit IC) has not detected any bipo-

lar signals at the MTIP and MRING inputs within the last 128 (32 bit-periods. If

this input signal is "low", then it means that bipolar signals are being detected

at the MTIP and MRING input pins of the XRT7300 device.

If this customer is not using the XR-T7300 DS3/E3 Line Interface Unit IC, then

he/she can use this input pin for a variety of other purposes.

VDD

****

Power Supply Pin

GND

****

Ground Pin

RxNib3

Receive Nibble Output - 3

The Framer IC will output "Received data (from the Remote Terminal) to the

local Terminal Equipment via this pin along with RxNib0, RxNib1 and RxNib2.

The data at this pin is updated on the rising edge of the RxClk output signal.

NOTE: This output pin is active only if the Nibble-Parallel Mode has been

selected.

RxNib2

Receive Nibble Output - 2

The Framer IC will output "Received data (from the Remote Terminal) to the

local Terminal Equipment via this pin along with RxNib0, RxNib1 and RxNib2.

The data at this pin is updated on the rising edge of the RxClk output signal.

NOTE: This output pin is active only if the Nibble-Parallel Mode has been

selected.

RxNib1

Receive Nibble Output - 1

The Framer IC will output "Received data (from the Remote Terminal) to the

local Terminal Equipment via this pin along with RxNib0, RxNib2 and RxNib3.

The data at this pin is updated on the rising edge of the RxClk output signal.

NOTE: This output pin is active only if the Nibble-Parallel Mode has been

selected.

PIN DESCRIPTION

PIN #NAME

TYPE

DESCRIPTION

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