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XRT79L71
PRELIMINARY
321
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
REV. P2.0.0
To transmit another (e.g., different) PMDL message to the remote Receive LAPD Controller, the user will have
to write this new message into the Transmit LAPD Message buffer, via the Microprocessor Interface section of
the channel. However, the user must be careful when writing in this new message. If the user writes this
message into the Transmit LAPD Message buffer at the wrong time (with respect to these one-second LAPD
Message frame transmissions), the user's action could interfere with these transmissions, thereby causing the
Transmit LAPD Controller to transmit a corrupted message to the remote Receive LAPD Controller. In order to
avoid this problem, while writing the new message into the Transmit LAPD Message buffer, the user should do
the following:
1.
Configure the DS3/E3 Framer Block to automatically reset activated interrupts
The user can do this by writing a "1" into Bit 1 (Enable Interrupt Auto-Clear) within the Operating Mode
Register - Byte 2, as depicted below.
This action will prevent the Transmit LAPD Controller from generating its own one-second interrupts.
2.
Enable the One-Second Interrupt
This can be done by writing a "1" into Bit 0 (One Second Interrupt Enable) within the Block Interrupt Enable
Register, as depicted below.
3.
Write the new message into the Transmit LAPD Message buffer immediately after the occurrence
of the One-Second interrupt.
By timing the writes to the Transmit LAPD Message buffer to occur immediately after the occurrence of the
One-Second interrupt, the user avoids conflicting with the one-second transmissions of the LAPD Message
frame, and will transmit the correct messages to the remote Receive LAPD Controller.
5.2.3.3
Transmit -LAPD Contro;ller Block Interrupt
5.2.4
TRANSMIT E3 FRAMER BLOCK
Operation Control Register - Byte 2 (Address = 0x0101)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
Interrupt
WC/INT*
Enable
Interrupt
Auto-Clear
Interrupt
Enable
R/O
R/W
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
0
1