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XRT79L71
PRELIMINARY
139
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
REV. P2.0.0
4.2.5.3
TRANSMITTING THE DS3 IDLE PATTERN
The Transmit DS3/E3 Framer block permits the user to transmit the DS3 Idle Pattern to the remote terminal
equipment upon software command. The Transmit DS3/E3 Framer block provides the user with two options
when transmitting the Idle Pattern.
Transmit the Bellcore GR-499-CORE standard Framed, Repeating 1, 1, 0, 0, … pattern.
Transmit a Framed, repeating user-defined pattern.
The procedure for transmitting either of these types of Idle patterns is presented below.
Transmitting the Bellcore GR-499-CORE standard Framed, Repeating 1, 1, 0, 0, … Pattern
The user can configure the Transmit DS3/E3 Framer block to transmit an Idle Pattern by transmitting a framed,
repeating 1, 1, 0, 0, … pattern. The user can accomplish this by executing the following steps.
STEP 1 - Set Bits 3 through 0 (Transmit_Idle_Pattern[3:0]) within the Transmit DS3 Pattern Register to
the value 1, 1, 0, 0, as illustrated below.
NOTE: This step configures the Transmit DS3/E3 Framer block to transmit a Framed, Repeating 1, 1, 0, 0, … pattern,
whenever the user commands it to transmit the Idle Pattern.
STEP 2 - Command the Transmit DS3/E3 Framer block to generate and transmit the DS3 Idle Pattern
This is accomplished by setting Bit 5 (TxIdle) within the Transmit DS3 Configuration Register to "1" as depicted
below.
Once the user executes this step, then the Transmit DS3/E3 Framer block will begin to generate and transmit a
Framed, Repeating 1, 1, 0, 0, … Pattern.
NOTE: The TxIdle bit-field is ignored whenever either Bits 3 (TxLOS) or 4 (TxAIS) are set to "1".
Transmitting the Framed, User-Defined DS3 Idle Pattern
The user can configure the Transmit DS3/E3 Framer block to transmit an Idle Pattern by transmitting a framed,
user-defined pattern. The user can accomplish this by executing the following steps.
STEP 1 - Set Bits 3 through 0 (Transmit_Idle_Pattern[3:0]) within the Transmit DS3 Pattern Register to
the user-defined four-bit value, as illustrated below.
Transmit DS3 Pattern Register (Address = 0x114C)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
TxAIS -
Unframed All
Ones
DS3 AIS
Non-Stuck
Stuff
Unused
TxLOS
Pattern
Transmit_Idle_Pattern[3:0]
R/W
R/O
R/W
0
1
0
Transmit DS3 Configuration Register (Address = 0x1130)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Tx Yellow
Alarm
Tx X-Bits
TxIdle
TxAIS
TxLOS
TxFERF
upon LOS
TxFERF
upon OOF
TxFERF
upon AIS
R/W
0
1
0
1