XRT7250 datasheet(291/463 Pages) EXAR

291 / 463 page

XRT7250

áç

DS3/E3 FRAMER IC

REV. 1.1.1

272

NOTE: This bit is ignored whenever the TxLOS bit-field is

set.

5.2.4.2.1.2

Transmit LOS Enable - Bit 1

This read/write bit field allows the user to transmit an

LOS (Loss of Signal) pattern to the remote terminal,

upon software control. Table 55 relates the contents

of this bit field to the Transmit E3 Framer block's ac-

tion.

NOTE: When this bit is set, it overrides all of the other bits in

this register.

5.2.4.2.1.3

Transmitting FERF (Far-End

Receive Failure) Indicator or Yellow Alarm

The XRT7250 Framer IC permits the user to control

the state of the “A” bit-field, within each outbound E3

frame. This can be achieved by writing the appropri-

ate data into the TxASource[1:0] bit-fields within the

Tx E3 Configuration Register, as illustrated below.

The following table presents the relationship between

the contents of TxASource[1:0] and the resulting

source of the “A” bit.

TABLE 54: THE RELATIONSHIP BETWEEN THE CONTENTS OF BIT 2 (TX AIS ENABLE) WITHIN THE TX E3

CONFIGURATION REGISTER, AND THE RESULTING TRANSMIT E3 FRAMER BLOCK'S ACTION

BIT 2TRANSMIT E3 FRAMER'S ACTION

Normal Operation:

The Transmit Section of the XRT7250 Framer IC will transmit E3 traffic based upon data that it accepts via the

Transmit Payload Data Input Interface block, the Transmit Overhead Data Input Interface block, the Transmit

HDLC Controller block and internally generated overhead bytes.

Transmit AIS Pattern:

The Transmit E3 Framer block will overwrite the E3 traffic, within an Unframed “All Ones” pattern.

TABLE 55: THE RELATIONSHIP BETWEEN THE CONTENTS OF BIT 1 (TX LOS) WITHIN THE TX E3 CONFIGURATION

BIT 1TRANSMIT E3 FRAMER'S ACTION

Normal Operation:

The Overhead bits are either internally generated, or they are inserted via the Transmit Overhead Data Input

Interface or the Transmit HDLC Controller blocks. The Payload bits are received from the Transmit Payload

Data Input Interface.

Transmit LOS Pattern:

When this command is invoked the Transmit E3 Framer will do the following.

• Set all of the overhead bytes to "0" (including the FA1 and FA2 bytes)

Overwrite the E3 payload bits with an "all zeros" pattern.

TXE3 CONFIGURATION REGISTER (ADDRESS = 0X30)

BIT 7BIT 6BIT 5BIT 4BIT 3BIT 2BIT 1BIT 0

BIP-4

Enable

TxASourceSel[1:0]

TxNSourceSel[1:0]

Tx AIS

Enable

Tx LOS

Enable

Tx FAS

Source

Select

R/W

000

XRT7250 Datasheet(PDF) 291 Page - Exar Corporation

XRT7250 Datasheet(HTML) 291 Page - Exar Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL