
PRELIMINARY
XRT79L71
486
REV. P2.0.0
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
STEP 8b - Enable the Transmit DS3/E3 Framer block Interrupts - At the Block Level.
This step is accomplished by setting Bit 1 (Transmit DS3/E3 Framer Block Interrupt Enable), within the Block
Interrupt Enable Register, to "1", as illustrated below.
STEP 8c - Enable the Transmit LAPD Interrupt at the Source Level.
This step is accomplished by setting Bit 1 (Transmit LAPD Interrupt Enable), within the Transmit E3 LAPD
Status/Interrupt Register to "1", as illustrated below.
STEP 9 - Command the Transmit LAPD Controller to begin its transmission.
At this point, it is finally time to command the Transmit LAPD Controller to do its job and transmit the loaded
PMDL Message to the remote terminal equipment.
The user accomplishes this by inducing a "0" to "1"
transition, within Bit 3 (Initiate Transmission of LAPD/PMDL Message) in the Transmit E3 LAPD Status/
Interrupt Register, as depicted below.
Once the user executes this step, then the Transmit LAPD Controller will proceed to do the following.
a. It will parse through the contents of the Transmit LAPD Message buffer and will zero-stuff the payload
portion of the outbound PMDL Message.
b. It will compute and append the Frame Check Sequence (FCS) value, to the back end of the outbound
PMDL Message.
c. It will begin in a byte-by-byte manner inserting the resulting PMDL Message into either the NR or the GC
byte-fields, depending upon user selection during STEP 2, within the outbound E3 frames.
Block Interrupt Enable Register (Address = 0x1104)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Receive DS3/
E3 Framer
Block Interrupt
Enable
Receive PLCP
Processor
Block Interrupt
Enable
Unused
Transmit DS3/
E3 Framer Block
Interrupt Enable
One Second
Interrupt Enable
R/W
R/O
R/W
X
0
1
X
Transmit E3 LAPD Status/Interrupt Register (Address = 0x1134)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
Initiate Transmission
of LAPD/PMDL Mes-
sage
Transmit LAPD
Controller Busy
Transmit LAPD
Interrupt
Enable
Transmit LAPD
Interrupt Status
RO
R/W
RO
R/W
RUR
0
1
0
Transmit E3 LAPD Status/Interrupt Register (Address = 0x1134)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
Initiate Transmission
of LAPD/PMDL Mes-
sage
Transmit LAPD
Controller Busy
Transmit LAPD
Interrupt
Enable
Transmit LAPD
Interrupt Status
RO
R/W
RO
R/W
RUR
0
0->1
0
1
0