XRT79L73 Datasheet, PDF (11/71 Pages) Exar Corporation – 3 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC

ÿþ
PRELIMINARY
3 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC
XRT79L73
REV. P1.0.0
PIN #
AD2
Y22
AB4
AC2
W26
AB3
G3
A26
J1
NAME
TxOH1/
TxHDLCDat1_5
TxOH2/
TxHDLCDat2_5
TxOH3/
TxHDLCDat3_5
TxOHIns1/
TxHDLCDat1_4
TxOHIns2/
TxHDLCDat2_4
TxOHIns3/
TxHDLCDat3_4
TxOHClk1
TxOHClk2
TxOHClk3
TYPE
DESCRIPTION
I Transmit Overhead Data Input/Transmit HDLC Controller Data Bit 5 input
pins:
I ^{The function of these input pins depend upon whether or not the XRT79L73 has}
been configured to operate in the High-Speed HDLC Controller Mode.
I
Non-High Speed HDLC Controller Mode - TxOH:
The Transmit Overhead Data Input Interface accepts overhead via these input
pins, and insert this data into the overhead bit positions within the outbound DS3
or E3 frames. If the TxOHIns input pins are pulled "High", then the Transmit
Overhead Data Input Interface will sample the overhead data, via these input
pins, upon the falling edge of the TxOHClk output signals.
Conversely, if the TxOHIns input pins are NOT pulled "High", then the Transmit
Overhead Data Input Interface block will be inactive and will not accept any over-
head data via the TxOH input pins.
High Speed HDLC Controller Mode - TxHDLCDat_5:
If the XRT79L73 is configured to operate in the High-Speed HDLC Controller
mode, then the local terminal equipment will be provided with a byte-wide Trans-
mit HDLC Controller byte-wide input interface. These input pins will function as
Bit 5 within this byte wide interface.
Data, residing on the Transmit HDLC Controller byte wide input interface, will be
sampled upon the rising edge of the TxHDLCClk output signals.
I Transmit Overhead Data Insert Input/Transmit HDLC Controller Data Bit 4
input pins:
I ^{The function of these input pins depend upon whether or not the XRT79L73 has}
been configured to operate in the High-Speed HDLC Controller Mode.
I
Non-High Speed HDLC Controller Mode - TxOHIns:
This input pins are used to either enable or disable the Transmit Overhead Data
Input Interface block. If the Transmit Overhead Data Input Interface block is
enabled, then it will accept overhead data from the local terminal equipment via
the TxOH input pins; and insert this data into the overhead bit positions within the
outbound DS3 or E3 data stream.
Conversely, if the Transmit Overhead Data Input Interface block is disabled, then
it will NOT accept overhead data from the local terminal equipment. Pulling
these input pins "High" enables the Transmit Overhead Data Input Interface
block. Pulling these input pins "Low" disables the Transmit Overhead Data Input
Interface block.
High-Speed HDLC Controller Mode - TxHDLCDat_4:
If the XRT79L73 is configured to operate in the High-Speed HDLC Controller
mode, then the local terminal equipment will be provided with a byte-wide Trans-
mit HDLC Controller byte-wide input interface. These input pins will function as
Bit 4 within this byte wide interface.
Data, residing on the Transmit HDLC Controller byte wide input interface, will be
sampled upon the rising edge of the TxHDLCClk output signals.
O Transmit Overhead Clock Output:
O These output pins functions as the Transmit Overhead Data Input Interface clock
O ^{signals. If the user enables the Transmit Overhead Data Input Interface block by}
asserting the TxOHIns input pins, then the Transmit Overhead Data Input Inter-
face block will sample and latch the data residing on the TxOH input pins upon
the falling edge of these signals.
NOTE: The Transmit Overhead Data Input Interface block is disabled if the user
has configured the XRT79L73 to operate in the High-Speed HDLC
Controller Mode.
9