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XRT79L71
PRELIMINARY
543
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
REV. P2.0.0
STEP 3 - Enable the Change in SSM Message Interrupt, at the "Source Level".
This is accomplished by setting Bit 6 (Change in SSM Message Interrupt Enable) within the "Receive E3
Interrupt Enable Register # 1 - G.832" to "1" as depicted below.
Once the user has executed these three steps, then the Receive SSM Controller block will be configured to
generate an interrupt request, anytime the Receive SSM Controller block detects a change in the SSM that it
receives and extracts out of the incoming E3 data-stream.
Servicing the Change of SSM Interrupt
If the "Change of SSM" Interrupt has been enabled, and if the XRT79L71 does generate the "Change of SSM"
Interrupt, then the user must service this particular interrupt by executing the following steps.
STEP 1 - Determine which kind of interrupt has been requested as the "Operational Block" Level
This is accomplished by reading out the contents of both the "Operation Interrupt Status Registers - Byte 1"
and "Byte 0" registers. The bit-format for each of these registers is presented below.
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
Receive E3 Interrupt Enable Register # 1 - G.832 (Address = 0x1112)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
Change in
SSM MSG
Interrupt
Enable
SSM OOS
Interrupt
Enable
COFA
Interrupt
Enable
Change in
OOF State
Interrupt
Enable
Change in
LOF State
Interrupt
Enable
Change in
LOS State
Interrupt
Enable
Change in
AIS State
Interrupt
Enable
R/O
R/W
0
1
0
Operation Interrupt Status Register - Byte 1 (Address = 0x0112)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
DS3/E3
LIU/JA
Block
Interrupt
Status
DS3/E3
Framer
Block
Interrupt
Status
Unused
R/O
0
1
0