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PRELIMINARY
XRT79L71
546
REV. P2.0.0
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
NOTE: Bits 6 and 7 (within the MA byte) are often referred to as carrying the "SSM Multi-Frame" indicator.
The Receive SSM Controller block contains circuitry that reads in and processes Bits 6 and 7 (within each
incoming MA byte) in order properly extract out the SSM message from the incoming E3 data-stream. As the
Receive SSM Controller block receives and processes the MA bytes of each incoming E3 frame, it expects Bits
6 and 7 to exhibit the repetitive sequence, as depicted above in Table 68.
Anytime the Receive SSM
Controller block detects something other than this sequence (via Bits 6 and 7, within each incoming MA byte),
then it will generate the "SSM Out-of-Sequence" Interrupt.
The purpose of the "SSM Out-of-Sequence"
Interrupt is to inform the user that the Receive SSM Controller block is (1) having difficulty locating the "Multi-
Frame" pattern within Bits 6 and 7 (of each incoming MA byte), and (2) is therefore having difficulty extracting
out an SSM message from the incoming E3 data-stream.
Enabling the SSM Out-of-Sequence Interrupt
To enable the SSM Out-of-Sequence Interrup, execute the following steps.
STEP 1 - Enable the "DS3/E3 Framer Block" for Interrupt Generation, at the "Operational Block" Level.
This can be accomplished by setting Bit 2 (DS3/E3 Framer Block Interrupt Enable) within the "Operation
Interrupt Enable Register - Byte 1" to "1" as depicted below.
STEP 2 - Enable the "Receive DS3/E3 Framer Block" for Interrupt Generation.
This can be accomplished by setting Bit 7 (Receive DS3/E3 Framer Block Interrupt Enable) within the "Framer
Block Interrupt Enable Register" to "1", as depicted below.
STEP 3 - Enable the "SSM Out-of-Sequence" Interrupt, at the "Source Level".
This is accomplished by setting Bit 5 (SSM OOS Interrupt Enable) within the "Receive E3 Interrupt Enable
Register # 1 - G.832" to "1" as depicted below.
Operation 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
Interrupt
Enable
DS3/E3
Framer Block
Interrupt
Enable
Unused
R/O
R/W
R/O
0
1
0
Framer 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
R/W
R/O
R/W
1
0