XRT79L71_1 Datasheet, PDF (73/434 Pages) Exar Corporation – 1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC -

XRT79L71
REV. 1.0.0
1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC - REGISTER/MAP DESCRIPTION
DS3/E3 FRAMER AND PLCP PROCESSOR BLOCK REGISTERS
DS/E3 FRAMER BLOCK REGISTERS
The register map for the DS3/E3 Framer Block is presented in the Table below. Additionally, a detailed
description of each of the ?DS3/E3 Framer? block registers is presented below
Framer Operating Mode Register (Address = 0x1100)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
Framer Local
Loop Back
IsDS3
Interna lLOS
Enable
RESET
Direct Map
ATM
R/W
R/W
R/W
R/W
R/W
0
0
1
0
1
BIT 2
Frame For-
mat
R/W
0
BIT 1
BIT 0
TimRefSel[1:0]
R/W
R/W
1
1
BIT NUMBER
NAME
7
Framer Local Loop Back
6
IsDS3
TYPE
R/W
R/W
DESCRIPTION
Framer Block Local Loop-back Mode:
This READ/WRITE bit field configures the XRT79L71 to operate
in the Framer Local Loop-back Mode. If the XRT79L71 has
been configured to operate in the Framer Local Loop-back
Mode, then the signal that is generated by the Transmit DS3/E3
Framer block will be internally looped back into the receive input
of the Receive DS3/E3 Framer block.
NOTE: Whenever the XRT79L71 has been configured into the
Framer Local Loop-back Mode, then the Transmit DS3/
E3 LIU and Receive DS3/E3 LIU Blocks will NOT be
operating in the Signal Path.
0 - Configures the XRT79L71 to operate in the Normal Operating
(e.g., Non-Framer Local Loop-back) Mode
1 - Configures the XRT79L71 to operate in the Framer Local
Loop-back Mode
Is DS3 Mode:
This READ/WRITE bit-field, along with Bit 2 (Frame Format),
permits the user to configure both the Transmit and Receive
DS3/E3 Framer blocks to operate in the appropriate framing for-
mat. The relationship between the state of this bit-field, Bit 2 and
the resulting framing format is presented below.
Bit 6 (IsDS3)
Bit 2 (Frame
Format)
Framing Format
0
0
E3, ITU-T G.751
0
1
E3, ITU-T G.832
1
0
DS3, C-bit Parity
1
1
DS3, M13
+
NOTE: These bit settings also configure the Transmit DS3/E3
LIU and Receive DS3/E3 LIU Blocks into either the DS3
or E3 Modes.
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