
19
x r
PRELIMINARY
E3 UNI FOR ATM
XRT7234
REV. P1.0.0
22
Encodis
O
Encoder (HDB3) Disable Output pin (intended to be connected to
the XR-T7296 E3 Line Transmitter IC).
This output pin is intended to be connected to the Encodis input pin of the
XR-T7296 E3 Line Transmitter IC. The user can control the state of this
output pin by writing a “0” or “1” to Bit 3 (Encodis) within the Line Inter-
face Driver Register (Address = 84h). If the user commands this signal to
toggle “high” then it will disable the HDB3 encoder circuitry within the XR-
T7296 IC. Conversely, if the user commands this output signal to toggle
“l(fā)ow”, then the HDB3 Encoder circuitry, within the XR-T7296 IC will be
enabled.
Writing a “1” to Bit 3 of the Line Interface Driver Register (Address = 84h)
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”.
Notes:
(1) The user is advised to disable the HDB3 encoder (within the XR-T7296 IC)
if the Transmit and Receive E3 Framers (within the UNI) are configured
to operate in the HDB3 line code.
(2) If the customer is not using the XR-T7296 E3 Line Transmitter IC,
then he/she can use this output pin for a variety of other purposes.
19
23
D2
I/O
Bi-directional Data bus (Microprocessor Interface Section):
(Please
see description for D15)
24
TxLev
O
Transmit Level Select Output (to be connected to the XR-T7296 E3
Line Transmit IC).
This output pin is intended to be connected to the TxLev input pin of the
XR-T7296 E3 Line Transmitter IC. The user can control the state of this
output pin by writing a “0” or a “1” to Bit 2 (TxLev) within the Line Inter-
face Driver Register (Address = 84h). If the user commands this signal to tog-
gle “high” then it will cause the XR-T7296 E3 Line Transmitter to increase
the amplitude of its output signal on the line, in order to drive the signal
over cable lengths of greater than 225 ft. Therefore, the user is recom-
mended to set this output “high”, if he/she is driving E3 line signals over
225 ft (or more) of cable. Conversely, if the user is driving E3 line signals
over less than 225 ft of cable, then he/she is recommended to set this out-
put pin “l(fā)ow”.
Writing a “1” to Bit 2 of the Line Interface Drive Register (Address = 84h)
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 XR-T7296 E3 Line Transmitter IC,
then he/she can use this output pin for a variety of other purposes.
20
25
D1
I/O
Bi-directional Data bus (Microprocessor Interface Section):
(Please
see description for D15)
PIN DESCRIPTION (CONTINUED)
Pin
No.
100 Pin Package
Pin No. 160
PinPackage
Symbol
Type
Description