
XRT7250
DS3/E3 FRAMER IC
á
REV. 1.1.1
6
38
D6
I/O
Bi-directional Data Bus (Microprocessor Interface Section):
Please see description for D7, pin 39
39
D7
I/O
MSB of Bi-Directional Data Bus (Microprocessor Interface Sec-
tion):
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.
40
VDD
****
Power Supply Pin
41
TxFrameRef
I
Transmit Framer Reference Input:
This input pin functions as the "Transmit Frame Generation" reference signal, if
the XRT7250 has been configured to operate in the "Local-Time/Frame Slave"
Mode. If the XRT7250 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 applications);
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 XRT7250
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 XRT7250 Framer IC to operate in the "Local
Time/Frame Slave" Mode by writing "xxxx xx01" into the "Framer Operating
Mode" Register (Address = 0x00).
42
GND
****
Ground Pin
43
TxInClk
I
Transmit Framer Reference Clock Input.
This input pin functions as the "Timing Reference" for the Transmit Section of
the XRT7250 Framer IC; if the device has been configured to operate in the
"Local-Time" Mode. Further, if the XRT7250 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 XRT7250 Framer IC to operate in the "Local-Time"
mode by writing "xxxx xx01" or "xxxx xx1x" into the "Framer Operating Mode"
register (Address = 0x00)
44
TxAISEn
I
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.
PIN DESCRIPTION
PIN #NAME
TYPE
DESCRIPTION