
XRT7245
DS3 UNI FOR ATM
á
PRELIMINARY
REV. 1.03
10
8
RLOL
I
Receive Loss of Lock Indicator—from the XRT7300 DS3/E3 LIU IC.
This input pin is intended to be connected to the RLOL (Receive Loss of Lock) output
pin of the XRT7300 LIU IC. The user can monitor the state of this pin by reading the
state of Bit 1 (RLOL) within the Line Interface Scan Register (Address = 73h). If this
input pin is “l(fā)ow”, then it means that the phase-locked-loop circuitry, within the XRT7300
device is properly locked onto the incoming DS3 data-stream; and is properly recover-
ing clock and data from this DS3 data-stream. However, if this input pin is “high”, then
it means that the phase-locked-loop circuitry, within the XRT7300 device has lost lock
with the incoming DS3 data-stream, and is not properly recovering clock and data.
For more information on the operation of the XRT7300 DS3/E3/STS-1 LIU IC, please
consult the "XRT7300 DS3/E3/STS-1 LIU IC" data sheet.
Note:
If the customer is not using the XRT7300 LIU IC, he/she can use this input pin
for other purposes.
9
D11
I/O
Bi-Directional Data bus (Microprocessor Interface Section):
10
TxFrame
O
Transmit End of DS3 Frame Indicator:
This output pin indicates that the last bit of an
outbound DS3 frame is being transmitted from the TxPOS and TxNEG output pins.
This pin marks the end of DS3 frame by pulsing “high” for one bit period at the end of each
frame.
11
D10
I/O
Bi-Directional Data bus (Microprocessor Interface Section):
This pin is inactive if
the Microprocessor Interface block is configured to operate over an 8 bit data bus.
(Please see description for D15)
12
REQB
O
Receive Equalization Bypass Control Output Pin—(to be connected to the
XRT7300 DS3/E3 LIU IC):
This output pin is intended to be connected to the REQB input pin of the XRT7300 DS3/
E3 LIU IC. The user can control the state of this output pin by writing a ‘0’ or ‘1’ to Bit 5
(REQB) of the Line Interface Driver Register (Address = 72h). If the user commands
this signal to toggle “high” then it will cause the incoming DS3 line signal to “by-pass”
equalization circuitry, within the XRT7300 Device. Conversely, if the user commands
this output signal to toggle “l(fā)ow”, then the incoming DS3 line signal with be routed
through the equalization circuitry. For information on the criteria that should be used
when deciding whether to bypass the equalization circuitry or not, please consult the
“XRT7300 DS3/E3/STS-1 LIU IC” data sheet.
Writing a “1” to Bit 5 of the Line Interface Drive Register (Address = 72h) will cause this
output pin to toggle “high”. Writing a “0” to this bit-field will cause this output pin to toggle
“l(fā)ow”.
Note:
If the customer is not using the XRT7300 DS3/E3/STS-1 LIU IC, then he/she
can use this output pin for a variety of other purposes.
13
D9
I/O
Bi-Directional Data bus (Microprocessor Interface Section):
This pin is inactive if
the Microprocessor Interface block is configured to operate over an 8 bit data bus.
(Please see description for D15)
14
D8
I/O
Bi-Directional Data bus (Microprocessor Interface Section):
This pin is inactive if
the Microprocessor Interface block is configured to operate over an 8 bit data bus.
(Please see description for D15)
15
VDD
***
Power Supply Pin
PIN DESCRIPTION (CONT’D)
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ESCRIPTION