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PRELIMINARY
XRT79L71
234
REV. P2.0.0
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
STEP 5 - Enable the Receive LAPD Interrupt (Optional).
This step is optional.
However, if this step is executed the XRT79L71 will generate an interrupt to the
Microprocessor anytime the Receive LAPD Controller block has completed its reception of a new PMDL
Message. The purpose of this interrupt is to notify the Microprocessor that the Receive LAPD Message buffer
contains a newly received LAPD/PMDL Message that needs to be read.
The procedure for enabling the Receive LAPD Interrupt is actually a three-step process.
STEP 5a - Enable the DS3/E3 Framer block interrupts - At the Operational Block Level.
This step is accomplished by setting Bit 2 (DS3/E3 Framer Block Interrupt Enable) to "1" as illustrated below.
This step enables the DS3/E3 Framer block for interrupt generation at the Operational Block Level.
STEP 5b - Enable the Receive DS3/E3 Framer block Interrupts - At the Block Level.
This step is accomplished by setting Bit 7 (Receive DS3/E3 Framer Block Interrupt Enable), within the Block
Interrupt Enable Register, to "1", as illustrated below.
This step enables the Receive DS3/E3 Framer block for interrupt generation, at the Block Level.
STEP 5c - Enable the Receive LAPD Interrupt at the Source Level.
This step is accomplished by setting Bit 1 (Receive LAPD Interrupt Enable), within the Receive DS3 LAPD
Control Register, as depicted below.
Receive DS3 LAPD Status Register (Address = 0x1119)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
RxABORT
RxLAPDType[1:0]
RxCR Type
RxFCS Error
End of
Message
Flag Present
R/O
0
1
Operation Block Interrupt Enable Register - Byte 1 (Address = 0x0116)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
DS3/E3 LIU/
JA Block Inter-
rupt Enable
DS3/E3
Framer Block
Interrupt
Enable
Unused
R/O
R/W
R/O
0
1
0
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
1
0
X