XRT72L58 Datasheet, PDF (27/486 Pages) Exar Corporation – EIGHT CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

áç
PRELIMINARY
XRT72L58
EIGHT CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. P1.1.2
PIN DESCRIPTION FOR THE XRT72L58
PIN #
B1
B2
PIN NAME
TxOHEnable[7]/
TxHDLCDat7[7]
TxFrame[7]
B3
TxSer[7]/
SndMsg[7]
B4
RxOHEnable[7]/
RxHDLCDat5[7]
B5
TxNib1[7]/
TxHDLCDat1[7]
B6
TxNib2[7]/
TxHDLCDat2[7]
B7
TxNibFrame[7]/
ValFCS[7]
B8
RxOOF[0]
TYPE
O
I
O
I
See Description of Pin A14
DESCRIPTION
Transmit End of DS3 or E3 Frame Indicator:
The Transmit Section of the XRT72L58 will pulse this output pin "high" (for
one bit-period), when the Transmit Payload Data Input Interface is processing
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 the XRT72L58 (e.g., to
permit the XRT72L58 to maintain Transmit DS3/E3 framing alignment control
over the Terminal Equipment).
See Description of Pin A24
O
See Description of Pin A17
I
Transmit Nibble-Parallel Payload Data Input -1:
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. The
Framer will take data, applied to this pin, and insert it into an outbound "E3 or
DS3" frame. The XRT72L58 will sample the data that is at these input pins,
upon the rising edge of the "TxNibClk" signal.
NOTE: This input pin is active only if the Nibble-Parallel Mode has been
selected.
Transmit HDLC Data Input - 1:
This pin accepts bit 1 TxHDLC data when the HDLC controller is turned on.
I
Transmit Nibble-Parallel Payload Data Input -2:
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. The
Framer will take data, applied to this pin, and insert it into an outbound "E3 or
DS3" frame. The XRT72L58 will sample the data that is at these input pins,
upon the rising edge of the "TxNibClk" signal.
NOTE: This input pin is active only if the Nibble-Parallel Mode has been
selected.
Transmit HDLC Data Input - 2:
This pin accepts bit 2 TxHDLC data when the HDLC controller is turned on.
O
See Description of Pin A12
O
Receiver "Out of Frame" Indicator:
The Receive Section of the XRT72L58 Framer will assert this output signal
whenever it has declared an "Out of Frame" (OOF) condition with the incom-
ing DS3 or E3 frames. This signal is negated when the framer correctly
locates the framing alignment bits or bytes and correctly aligns itself with the
incoming DS3 or E3 frames.
8