XRT72L50 Datasheet, PDF (19/471 Pages) Exar Corporation – SINGLE CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

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PIN DESCRIPTION
PIN #
37
PIN NAME
D(5)
38
D(6)
39
D(7)
40
VDD
41
TxFrameRef
42
GND
43
TxInClk
44
TxAISEn
XRT72L50
SINGLE CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. 1.2.1
TYPE
I/O
I/O
I/O
****
I
****
I
I
DESCRIPTION
Bit 5 of Bi-Directional Data Bus (Microprocessor Interface Section):
See description of pin 39 D(7)
Bit 6 of Bi-Directional Data Bus (Microprocessor Interface Section):
See description of pin 39 D(7)
MSB of Bi-Directional Data Bus (Microprocessor Interface Section):
This pin, along with pins D0 - D6, function as the Microprocessor Interface bi-
directional data bus, and is intended to be interfaced to the local microproces-
sor.
Power Supply 3.3V + 5%
Transmit Framer Reference Input:
This input pin functions as the Transmit Frame Generation reference signal, if
the XRT72L50 has been configured to operate in the Local-Time/Frame Slave
Mode. If the XRT72L50 has been configured to operate in the Local-Time/
Frame-Slave Mode, then the user's terminal equipment is expected to apply a
pulse (to this input pin) once every 106.4 microseconds (for DS3 applica-
tions); once every 125 microseconds (for E3, ITU-T G.832 applications) or
once every 44.7 microseconds (for E3, ITU-T G.751 applications).
In the Local-Time/Frame-Slave Mode, the Transmit Section of the XRT72L50
Framer IC will initiate its generation of a new outbound DS3 or E3 frame, upon
the rising edge of this signal.
NOTE: The user can configure the XRT72L50 Framer IC to operate in the
Local Time/Frame Slave Mode by writing xxxx xx01 into the Framer Operating
Mode Register (Address = 0x00).
Ground
Transmit Framer Reference Clock Input:
This input pin functions as the Timing Reference for the Transmit Section of
the XRT72L50 Framer IC; if the device has been configured to operate in the
Local-Time Mode. Further, if the XRT72L50 Framer IC has been configured to
operate in the Local-Time Mode, the Transmit Payload Data Input Interface
will sample the data at the TxSer input pin, upon the rising edge of TxInClk.
For E3 applications, the user should apply a 34.368MHz clock signal. For DS3
applications, the user should apply a 44.736MHz clock signal.
The user can configure the XRT72L50 Framer IC to operate in the Local-Time
mode by writing xxxx xx01 or xxxx xx1x into the Framer Operating Mode reg-
ister (Address = 0x00)
Transmit AIS Command Input:
Setting this input pin "High" configures the Transmit Section to generate and
transmit an AIS Pattern.
Setting this input pin "Low" configures the Transmit Section to generate E3 or
DS3 traffic in a normal manner.
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