XRT72L13 Datasheet, PDF (254/370 Pages) Exar Corporation – M13 MULTIPLEXER/CLEAR CHANNEL DS3 FRAMER IC

XRT72L13
M13 MULTIPLEXER/CLEAR CHANNEL DS3 FRAMER IC
REV. P1.0.6
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PRELIMINARY
FIGURE 68. BEHAVIOR OF THE TERMINAL INTERFACE SIGNALS BETWEEN THE XRT72L13 AND THE TERMINAL
EQUIPMENT (DS3 MODE 3 OPERATION)
Terminal Equipment Signals
DS3_Clock_In
DS3_Data_Out
Tx_Start_of_Frame
DS3_Overhead_Ind
Payload[4702] Payload[4703]
X-Bit
Payload[1]
XRT72L13 Transmit Payload Data I/F Signals
TxInClk
TxSer
Payload[4702] Payload[4703]
TxFrame
TxOH_Ind
X-Bit
Payload[1]
DS3 Frame Number N
Note: TxFrame pulses high to denote
DS3 Frame Boundary.
Note: TxOH_Ind pulses high to
denote Overhead Data
(e.g., the X-bit).
DS3 Frame Number N + 1
Note: X-Bit will not be processed by the
Transmit Payload Data Input Interface.
How to configure the XRT72L13 to operate in this
mode.
1. Set the "NibIntf" input pin "low".
OPERATING MODE REGISTER (ADDRESS = 0X00)
2. Set the "TimRefSel[1:0] bit-fields (within the
"Framer Operating Mode Register") to "10” or
“11" as depicted below.
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT2
BIT 1
BIT 0
Local Loop-
back
Mode
Line Loop-
back
Mode
Internal LOS
Enable
RESET
R/W
R/W
R/W
R/W
0
0
1
0
3. Interface the XRT72L13, to the Terminal Equip-
ment, as illustrated in Figure 67 .
4.2.1.4 Mode 4 - The "Nibble-Parallel/Loop-
Timed" Mode
Behavior of the XRT72L13
Interrupt
Enable
Reset
Frame Format
TimRefSel[1:0]
R/W
R/W
R/W
R/W
1
0
1
X
If the XRT72L13 has been configured to operate in
this mode, then the XRT72L13 devide will behave as
follows.
A. Looped Timing (Uses the RxLineClk as the
Timing Reference)
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