XRT74L73
3 CHANNEL, ATM UNI/PPP DS3/E3 FRAMING CONTROLLER
REV. P1.0.1
PRELIMINARY
447
within the Rx E3 Framer Interrupt Status Register -
1.
Clearing the RxAIS output pin (e.g., toggling it
"Low”).
Setting the RxAIS bit-field, within the Rx E3 Config-
uration & Status Register to “0”, as depicted below.
6.3.2.6.3
Condition
Declaring the FERF Condition
The Receive E3 Framer block will declare a Far-End
Receive Failure (FERF) condition if it detects a user-
The Far-End-Receive Failure (FERF)
selectable number of consecutive incoming E3
frames, with the FERF bit-field (Bit 7, within the MA
Byte) set to “1”. Recall, the bit-format of the MA byte
is presented below.
This User-selectable number of E3 frames is either 3
or 5, depending upon the value that has been written
into Bit 4 (Rx FERF Algo) within the Rx E3 Configura-
tion & Status Register, as depicted below.
Writing a “0” into this bit-field causes the Receive E3
Framer block to declare a FERF condition, if it detects
3 consecutive incoming E3 frames, that have the
FERF bit (within the MA byte) set to “1”.
Writing a “1” into this bit-field causes the Receive E3
Framer block to declare a FERF condition, if it detects
5 consecutive incoming E3 frames, that have the
FERF bit (within the MA byte) set to “1”.
Whenever the Receive E3 Framer block declares a
FERF condition, then it will do the following.
Generate a Change in FERF Condition interrupt to
the MIcroprocessor. Hence, the Receive E3
Framer block will assert Bit 3 (FERF Interrupt Sta-
tus) within the Rx E3 Framer Interrupt Status regis-
ter - 2, as depicted below.
RXE3 CONFIGURATION & STATUS REGISTER 2 (ADDRESS = 0X11)
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
Rx LOF Algo
RxLOF
RxOOF
RxLOS
RxAIS
RxPld Unstab
Rx
TMark
RxFERF
R/W
RO
RO
RO
RO
RO
RO
RO
0
0
0
0
0
0
0
0
THE MAINTENANCE AND ADAPTATION (MA) BYTE FORMAT
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
FERF
FEBE
Payload Type
Payload Dependent
Timing Marker
RXE3 CONFIGURATION & STATUS REGISTER 1 - (E3, ITU-T G.832) (ADDRESS = 0X10)
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
RxPLDType[2:0]
RxFERF
Algo
RxTMark
Algo
RxPLDExp[2:0]
RO
RO
RO
RO
RO
RO
RO
RO
0
0
0
0
0
0
0
0