XRT72L53 Datasheet, PDF (19/467 Pages) Exar Corporation – THREE CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

XRT72L53
THREE CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. P1.1.7
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PRELIMINARY
PIN DESCRIPTION CONNECTED PINS
PIN #
E18
PIN NAME
TxSer[0]/
SndMsg[0]
E19
TxOHInd[0]/
TxHDLCDat6[0]
E20
TxFrame[0]
TYPE
I
O
I
O
DESCRIPTION
Transmit Serial Payload Data Input pin/Transmit HDLC Controller -
SEND MESSAGE Input pin - Channel 0:
The exact function of this input pin depends upon whether Channel 0
has been configured to operate in the “High-Speed HDLC Controller”
Mode or not.
Non-High-Speed HDLC Controller Mode - Transmit Serial Payload
Data Input Pin - Channel 0:
The Terminal Equipment is expected to input data, that is intended to be
transmitted to the remote terminal, over an E3 or DS3 transport
medium, to this input pin. The Transmit Section of Channel 0 will take
data, applied to this pin, and insert it into an outbound E3 or DS3 frame.
If Channel 0 has been configured to operate in the Local Time Mode,
then it will sample the data (on this pin) upon the rising edge of TxIn-
Clk[0]. If Channel 0 has been configured to operate in the Loop-Time
Mode, then it will sample the data (on this pin) upon the rising edge of
RxOutClk[0].
NOTE: This input pin is active only if the Serial Mode has been selected.
High-Speed HDLC Controller Mode - Transmit HDLC SEND MES-
SAGE Input - Channel 0:
The Terminal Equipment is expected to pull this input pin high during
the entire duration of the HDLC packet (including FCS bytes) to be
transmitted, when the HDLC controller is turned on.
Transmit Overhead Data Indicator Output/Transmit HDLC Data
Input - 6:
The exact function of this pin depends upon whether Channel0 has
been configured to operate in the “High-Speed HDLC Controller” Mode,
or not.
Non-High-Speed HDLC Controller Mode -Transmit Overhead Data
Indicator Output - Channel 0:
This output pin will pulse "High" one-bit period prior to the time that the
Transmit Section of Channel 0 will be processing an Overhead bit. The
purpose of this output pin is to warn the Terminal Equipment that, dur-
ing the very next bit-period, Channel 0 is going to be processing an
Overhead bit and will be ignoring any data that is applied to the
TxSer[0] input pin.
NOTE: For DS3 applications, this output pin is only active if Channel 0 is
operating in the Serial Mode. This output pin will be pulled "Low" if
Channel 0 is operating in the Nibble-Parallel Mode.
Transmit HDLC Data Input - Bit 6:
This input pin functions as bit 6, within the byte-wide Transmit HDLC
Controller Input interface (TxHDLCDat[7:0]), whenever Channel 0 has
been configured to operate in the “High-Speed HDLC Controller” Mode.
Transmit End of DS3 or E3 Frame Indicator - Channel 0:
The Transmit Section of Channel 0 will pulse this output pin "High" (for
one bit-period), when the Transmit Payload Data Input Interface is pro-
cessing the last bit of a given DS3 or E3 frame.
The purpose of this output pin is to alert the Terminal Equipment that it
needs to begin transmission of a new DS3 or E3 frame to Channel 0
(e.g., to permit Channel 0, within the XRT72L53 device to maintain
Transmit DS3/E3 framing alignment control over the Terminal Equip-
ment).
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