XRT72L54 Datasheet, PDF (23/484 Pages) Exar Corporation – FOUR CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

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PRELIMINARY
PIN DESCRIPTION
PIN #
PIN NAME
A14
TxOHClk[0]
A15
TxOH[0]/
TxHDLCDat5[0]
A16
TxNib2[1]/
TxHDLCDat2[1]
A17
RxSer[1]/
RxIdle[1]
A18
TxOHInd[1]/
TxHDLCDat6[1]
A19
RxOHInd[1]
A20
RxClk[1]
B1
TDI
XRT72L54
FOUR CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. P1.1.2
TYPE
O
I
I
O
O
I
O
O
I
DESCRIPTION
Transmit Overhead Clock:
This output signal serves two purposes:
1. The Transmit Overhead Data Input Interface block will provide a rising
clock edge on this signal, one bit-period prior to the start to the instant
that the “Transmit Overhead Data Input Interface” block is processing an
overhead bit.
2. The Transmit Overhead Data Input Interface will sample the data at
the “TxOH” input pin, on the falling edge of this clock signal (provided
that the “TxOHIns” input pin is “HIGH”).
NOTE: The Transmit Overhead Data Input Interface block will supply a
clock edge for all overhead bits within the DS3 or E3 frame (via the
“TxOHClk” output signal). This includes those overhead bits that the
“Transmit Overhead Data Input Interface” will not accept from the Termi-
nal Equipment.
Transmit Overhead Input Pin:
The Transmit Overhead Data Input Interface accepts the overhead data
via this input pin, and inserts into the "overhead" bit position within the
very next "outbound" DS3 or E3 frame. If the "TxOHIns" pin is pulled
"high", the Transmit Overhead Data Input Interface will sample the data
at this input pin (TxOH), on the falling edge of the "TxOHClk" output pin.
Conversely, if the "TxOHIns" pin is pulled "low", then the Transmit Over-
head Data Input Interface will NOT sample the data at this input pin
(TxOH). Consequently, this data will be ignored.
Transmit HDLC Data Input - 5:
This pin accepts bit 5 TxHDLC data when the HDLC controller is turned
on.
See Description for Pin C20
See Description for Pin F19
See Description for Pin E19
See Description for Pin G18
See Description for Pin D20
Test Data In: Boundary Scan Test data input.
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