30
x r
PRELIMINARY
E3 UNI FOR ATM
XRT7234
REV. P1.0.0
72
109
TxPOS
O
Transmit Positive Polarity Pulse:
The exact role of this output pin depends
upon whether the UNI is operating in the Unipolar or Bipolar Mode.
Unipolar Mode:
This output pin functions as the “Single-Rail” output sig-
nal for the “outbound” E3 data stream. The signal, at this output pin, will
be updated on the “user-selected” edge of the TxLineClk signal.
Bipolar Mode:
This output pin functions as one of the two dual rail output
signals that commands the sequence of pulses to be driven on the line.
TxNEG is the other output pin. This input is typically connected to the
TPDATA input of the external E3 Line Interface Unit IC. When this output
is asserted, it will command the LIU to generate a positive polarity pulse
on the line.
110
NC
****
Not Bonded Out
73
111
TxNEG
O
Transmit Negative Polarity Pulse:
The exact role of this output pin depends
upon whether the UNI is operating in the Unipolar or Bipolar Mode.
Unipolar Mode:
This output signal pulses “high” for one bit period, at the
end or each “outbound” E3 frame. This output signal is at a logic “l(fā)ow” for
all of the remaining bit-periods of the “outbound” E3 frames
Bipolar Mode:
This output pin functions as one of the two dual-rail output
signals that commands the sequence of pulses to be driven on the line.
TxPOS is the other output pin. This input is typically connected to the
TNDATA input of the external E3 Line Interface Unit IC. When this output
is asserted, it will command the LIU to generate a negative polarity pulse
on the line.
74
112
TxLineClk
O
Transmit Line Interface Clock:
This clock signal is output to the Line
Interface Unit, along with the TxPOS and TxNEG signals. The purpose
of this output clock signal is to provide the LIU with timing information
that it can use to generate the AMI pulses and deliver them over the trans-
mission medium to the Far-End Receiver. The user can configure the
source of this clock to be either the RxLineClk (from the Receiver portion
of the UNI) or the TxInClk input. The nominal frequency of this clock sig-
nal is 34.368 MHz.
75
113
VDD
***
Power Supply Pin
114
NC
****
Not Bonded Out
76
115
TxAISEn
I
Transmit AIS Pattern input:
When this input pin is set “high” the Transmit
E3 Framer will insert the AIS (e.g., an all “1s”) pattern into the E3 output
data stream.
116
NC
****
Not Bonded Out
PIN DESCRIPTION (CONTINUED)
Pin
No.
100 Pin Package
Pin No. 160
PinPackage
Symbol
Type
Description