XRT7250 datasheet(112/463 Pages) EXAR

112 / 463 page

áç

DS3/E3 FRAMER IC

XRT7250

REV. 1.1.1

This Read/Write byte-fields allows the user to specify

the contents of the MA byte-field in each outbound E3

frame.

NOTE: The values written into bit-fields 6 (FEBE) and 7

(FERF) are inserted into outbound E3 frames, only if bit-

field 0 (MAx) within the Tx E3 Configuration Register

(Address = 28h) is set to "0". Otherwise, the Transmit E3

Framer will set the FERF and FEBE values, within each

outbound E3 frame, to values based upon Receive E3

Framer conditions.

2.3.6.6

Transmit E3 NR Byte Register (E3, ITU-

T G.832)

This Read/Write byte-field allows the user to specify

the contents of the NR byte-field in each outbound E3

frame.

NOTE: The contents of this register is ignored, if the LAPD

Transmitter is enabled and has been configured to insert

the comprising octets of an outbound LAPD Message

frame into the NR byte-field of each outbound E3 frame

(e.g., if DLinNR = "1").

2.3.6.7

Transmit E3 TTB-0 Register (E3, ITU-T

G.832)

This Read/Write byte-field, along with the Tx TTB-1

through Tx TTB-15 registers allows a user to define a

Trail Access Point Identifier sequence of bytes, that

will be transmitted to the Far-End Terminal. The Far-

End Receiving Terminal will use this sequence of

bytes to verify that it is connected to the proper Trans-

mitting Terminal. The Transmit E3 Framer will take

the contents of these 16 registers, and insert them in-

to the TR byte of the outbound E3 frame. In the first

of a set of 16 E3 Frames, the Transmit E3 Framer will

read in the contents of this register, and insert it into

the TR byte-field, within the very next outbound E3

frame.

This particular byte-field should contain the pattern

"[1, C6, C5, C4, C3, C2, C1, C0]" where C6 through

C0 are the results of a CRC-7 calculation over the

previous 16-byte frame.

NOTE: The XRT7250 Framer IC will not compute this CRC-

7 value. It is up to the user's hardware and/or software to

compute this value, prior to writing it into this register.

2.3.6.8

Transmit E3 TTB-1 Register (E3, ITU-T

G.832)

TXE3 MA BYTE REGISTER (ADDRESS = 0X36)

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

Transmit MA Byte

FERF

FEBE

Payload Type

Payload Dependent

Timing

Marker

R/W

0010

000

TXE3 NR BYTE REGISTER (ADDRESS = 0X37)

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

TxNR[7:0]

R/W

0010

000

TXE3 TTB-0 REGISTER (ADDRESS = 0X38)

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

TxTTB0[7:0]

R/W

0010

000

XRT7250 датащи(PDF) 112 Page - Exar Corporation

XRT7250 датащи(HTML) 112 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

датащи скачать

ссылки URL