
á
PRELIMINARY
DS3 UNI FOR ATM
XRT7245
REV. 1.03
9
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Pin Descriptions (see Figure 2)
PIN DESCRIPTION
P
IN
N
O
.
S
YMBOL
T
YPE
D
ESCRIPTION
1
D15
I/O
MSB of Bi-Directional Data Bus (Microprocessor Interface Section):
This pin,
along with pins D0 - D14, function as the Microprocessor Interface bi-directional data
bus, and is intended to be interfaced to the “l(fā)ocal” microprocessor. This pin is inactive
if the Microprocessor Interface block is configured to operate over an 8 bit data bus.
2
TAOS
O
“Transmit All Ones Signal” (TAOS) Command (for the XR-T7296 DS3 Line
Transmitter IC).
This output pin is intended to be connected to the TAOS input pin of the XR-T7296
DS3 Line Transmitter IC. The user can control the state of this output pin by writing a
‘0’ or ‘1’ to Bit 4 (TAOS) of the Line Interface Drive Register (Address = 72h). If the
user commands this signal to toggle "high" then it will force the XR-T7296 DS3 Line
Transmitter IC to transmit an "All Ones" pattern onto the line. Conversely, if the user
commands this output signal to toggle "low" then the XR-T7296 DS3 Line Transmitter
IC will proceed to transmit data based upon the pattern that it receives via the TxPOS
and TxNEG output pins.
Writing a "1" to Bit 4 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
"low".
Note:
If the customer is not using the XR-T7296 DS3 Line Transmitter IC, then he/she
can use this output pin for a variety of other purposes.
3
D14
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)
4
D13
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)
5
D12
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)
6
DMO
I
“Drive Monitor Output” Input (from the XRT7300 LIU IC).
This input pin is intended to be tied to the DMO output pin of the XRT7300 DS3/E3
LIU IC. The user can determine the state of this input pin by reading Bit 2 (DMO)
within the Line Interface Scan Register (Address = 73h). If this input signal is “high”,
then it means that the drive monitor circuitry (within the XRT7300 LIU IC) has not
detected any bipolar signals at the MTIP and MRING inputs within the last 128 ± 32
bit-periods. If this input signal is “l(fā)ow”, then it means that bipolar signals are being
detected at the MTIP and MRING input pins of the XRT7300 device.
Note:
If this customer is not using the XRT7300 DS3 LIU IC, then he/she can use this
input pin for a variety of other purposes.
7
MOTO
I
Motorola/Intel Processor Interface Select Mode:
This input pin allows the user to
configure the Microprocessor Interface to interface with either a “Motorola-type” or
“Intel-type” microprocessor/microcontroller. Tying this input pin to VCC, configures the
microprocessor interface to operate in the Motorola mode (e.g., the UNI device can be
readily interfaced to a “Motorola type” local microprocessor). Tying this input pin to
GND configures the microprocessor interface to operate in the Intel Mode (e.g., the
UNI device can be readily interfaced to an “Intel type” local microprocessor).