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XRT79L71
PRELIMINARY
127
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
REV. P2.0.0
This is accomplished by reading out the contents of the Frame Operating Mode Register (Address = 0x1100)
and verifying that Bit 6 (DS3/E3*) is set to "1" and that Bit 2 (Frame Format) is set to "0", as illustrated below.
STEP 2 - Enable the Transmit LAPD Controller
This is accomplished by setting Bit 0 (Transmit LAPD Enable) within the Transmit DS3 LAPD Configuration
register to "1", as illustrated below.
NOTE: Once the user executes the above-mentioned step, then the Transmit LAPD Controller will begin to transmit the Idle
(Flag) Sequence (e.g., a repeating string of 0x7E) to the remote terminal equipment.
STEP 3 - Configure the Transmit LAPD Controller to transmit a non-standard size LAPD Message.
This is accomplished by setting Bit 7 (LAPD Any) within the Transmit DS3 LAPD Configuration Register to "1",
as illustrated below.
STEP 4 - Configure the Transmit LAPD Controller to Auto-Retransmit (Optional)
In some applications, it may be desirable to configure the Transmit LAPD Controller to repeatedly transmit a
PMDL Message at one-second intervals. To configure the Transmit LAPD Controller block to do this, then the
user should write a "1" into Bit 3 (Auto-Retransmit) within the Transmit DS3 LAPD Configuration register. This
operation is depicted below.
Framer Operating Mode Register (Address = 0x1100)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Local
Loop-back
DS3/E3*
Internal
LOS Enable
RESET
Direct
Mapped ATM
Frame For-
mat
Timing Reference Select [1:0]
R/W
X
1
X
0
X
0
X
Transmit DS3 LAPD Configuration Register (Address = 0x1133)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
LAPD Any
Unused
Auto
Retransmit
Unused
Transmit LAPD
Message Length
Transmit
LAPD Enable
R/W
RO
R/O
R/W
R/O
R/W
1
0
X
1
Transmit DS3 LAPD Configuration Register (Address = 0x1133)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
LAPD Any
Unused
Auto
Retransmit
Unused
Transmit LAPD
Message Length
Transmit
LAPD Enable
R/W
RO
R/O
R/W
R/O
R/W
1
0
X
1