XRT86L30
REV. 1.0.1
SINGLE T1/E1/J1 FRAMER/LIU COMBO
The E1 Transmit Overhead Input Interface Block will allow an external device to be the provider of the E1
National bit sequence. This interface provides interface signals and required interface timing to shift in proper
data link information at proper time.
The Transmit Overhead Input Interface for a given Framer consists of two signals.
•
•
TxOHClk_n: The Transmit Overhead Input Interface Clock Output signal
TxOH_n: The Transmit Overhead Input Interface Input signal.
The Transmit Overhead Input Interface Clock Output pin (TxOHCLK_n) generates a rising clock edge for each
National bit that is configured to carry Data Link information according to setting of the framer. The Data Link
equipment interfaced to the Transmit Overhead Input Interface should update the data link bits on the TxOH_n
line upon detection of the rising edge of TxOHClk_n. The Transmit Overhead Input Interface block will sample
and latch the data link bits on the TxOH_n line on the falling edge of TxOHClk_n. The data link bits will be
included in and transmitted via the outgoing E1 frames.
The figure below shows block diagram of the DS1 Transmit Overhead Input Interface of XRT86L30.
FIGURE 44. BLOCK
D
IAGRAM OF THE E1 TRANSMIT
O
VERHEAD
INPUT
INTERFACE OF XRT86L30
TxOH_n
TxOHClk_n
Transmit
Overhead Input
Interface
To Transmit
Framer Block
7.4.2
Configure the E1 Transmit Overhead Input Interface module as source of the National Bit
Sequence in E1 framing format mode
The National Bit Sequence in E1 framing format mode can be inserted from:
•
•
•
E1 Transmit Overhead Input Interface Block
E1 Transmit HDLC Controller
E1 Transmit Serial Input Interface
The purpose of the Transmit Overhead Input Interface is to permit Data Link equipment direct access to the
Sa4 through Sa8 National bits that are to be transported via the outbound frames. The Transmit Data Link
Source Select [1:0] bits, within the Synchronization MUX Register (SMR) determine source of the Sa4 through
Sa8 National bits to be inserted into the outgoing E1 frames.
The table below shows configuration of the Transmit Data Link Source Select [1:0] bits of the Synchronization
MUX Register (SMR).
SYNCHRONIZATION MUX REGISTER (SMR) (ADDRESS = 0X0109H)
B
IT
B
IT
N
AME
B
IT
TYPE
BIT DESCRIPTION
N
UMBER
3-2
Transmit Data Link
Source Select [1:0]
R/W
00 - The Sa4 through Sa8 National bits are inserted into the framer
through the Transmit Serial Data input Interface via the TxSer_n pins.
01 - The Sa4 through Sa8 National bits are inserted into the framer
through the Transmit LAPD Controller.
10 - The Sa4 through Sa8 National bits are inserted into the framer
through the Transmit Overhead Input Interface via the TxOH_n pins.
11 - The Sa4 through Sa8 National bits are inserted into the framer through
the Transmit Serial Data input Interface via the TxSer_n pins.
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EXAR [ EXAR CORPORATION ]
