IDT82V2108
T1 / E1 / J1 OCTAL FRAMER
Functional Description
16
March 5, 2009
When the above status has lasted for 100 ms, AIS alarm is
declared with a logic ‘1’ in the AIS (b2, E1-037H). However, in unframed
mode, the detection of AIS alarm is disabled.
3.2.1.2.3
Bit Extraction
The Frame Processor extracts the National Bit codeword (Sa4[1:4]
to Sa8[1:4] in the CRC Sub Multi-Frame), the International bit (Si), the
National bit (Sa), the Remote Alarm Indication bit (A), the Extra bits (X)
and the Remote Signaling Multi-Frame Alarm Indication bit (Y).
- National Bit Codeword
The Frame Processor extracts one of the National Bit codewords
(Sa4[1:4] to Sa8[1:4] in the CRC Sub Multi-Frame) to the SaX[1:4]
(b3~0, E1-03DH). Here the ‘X’ is selected from 4 to 8 by the SaSEL[2:0]
(b7~5, E1-03BH). The SaX[1:4] (b3~0, E1-03DH) are debounced. They
are updated only when two consecutive codewords are the same.
- International Bit
The International bits (Si) are extracted to the Si[1:0] (b7~6, E1-
038H). The Si[1:0] (b7~6, E1-038H) are updated on the boundary of the
associated FAS/NFAS frame and are not updated when out of frame is
reported.
- National Bit
The National bits (Sa) are extracted to the Sa[4:8] (b4~0, E1-
038H). The Sa[4:8] (b4~0, E1-038H) are updated on the boundary of the
associated NFAS frame and are not updated when out of frame is
reported.
- Remote Alarm Indication Bit
The Remote Alarm Indication bit (A) is extracted to the A (b5, E1-
038H). The A (b5, E1-038H) is updated on the boundary of the associ-
ated NFAS frame.
- Extra Bit
The Extra bits (X) are extracted to the X[0:2] (b5 & b3~2, E1-
03AH). The X[0:2] (b5 & b3~2, E1-03AH) are updated on the beginning
of the Frame1 (next NFAS frame).
- Remote Signaling Multi-Frame Alarm Indication Bit
The Remote Signaling Multi-Frame Alarm Indication bit (Y) is
extracted to the Y (b4, E1-03AH). The Y (b4, E1-03AH) is updated on
the beginning of the Frame1 (next NFAS frame).
3.2.1.2.4
V5.2 Link
The V5.2 link ID signal, i.e. 2 out of 3 Sa7 bits being logic 0, is
detected with the indication in the V52LINKV (b0, E1-036H).
3.2.1.3
Interrupt Sources
24 kinds of interrupts are derived from this block as shown in
Table 2. When there are conditions meeting the interrupt sources, the
corresponding Status bit will be asserted high. When there is a transition
(‘1’ to ‘0’ or ‘0’ to ‘1’) on the Status bit, the corresponding Status Interrupt
Indication bit will be set to logic 1 (If the Status bit does not exist, the
source will cause its Status Interrupt Indication bit to logic 1 directly) and
the Status Interrupt Indication bit will be cleared when it is read. A logic 1
in the Status Interrupt Indication bit means an interrupt occurred. The
interrupt will be reported by the INT pin if its Status Interrupt Enable bit is
logic 1.
Table 2: Interrupt Sources in the E1 Frame Processor
No.
Sources
Status Bit
Interrupt Indication Bit
Interrupt Enable Bit
1 The received Basic Frame alignment signal does not meet its pattern once Basic
Frame synchronization is achieved.
-
FERI (b2, E1-034H)
FERE (b2, E1-032H)
2 The received CRC Multi-Frame alignment signal does not meet its pattern once
CRC Multi-Frame synchronization is achieved.
-
CMFERI (b0, E1-034H)
CMFERE (b0, E1-032H)
3 The received Signaling Multi-Frame alignment signal does not meet its pattern
once Signaling Multi-Frame synchronization is achieved.
-
SMFERI (b1, E1-034H)
SMFERE (b1, E1-032H)
4 The received data stream is out of Basic Frame synchronization when any of the
following conditions is met:
1) The Basic Frame has not been synchronized.
2) The received data stream meets the out of Basic Frame synchronization criteria
set in the BIT2C (b6, E1-031H).
3) There are excessive CRC errors in the received data stream.
OOFV (b6, E1-
036H)
OOFI (b6, E1-034H)
OOFE (b6, E1-032H)
5 The received data stream is out of CRC Multi-Frame synchronization when any of
the following conditions is met:
1) The CRC Multi-Frame has not been synchronized.
2) There are excessive CRC errors in the received data stream.
OOCMFV (b4,
E1-036H)
OOCMFI (b4, E1-034H)
OOCMFE (b4, E1-032H)
6 The received data stream is out of Signaling Multi-Frame synchronization when
any of the following conditions is met:
1) The received data stream is out of Basic Frame synchronization.
1) The received data stream meets the out of Signaling Multi-Frame synchroniza-
tion criteria set in the SMFASC (b5, E1-031H) and the TS16C (b4, E1-031H).
OOSMFV (b5,
E1-036H)
OOSMFI (b5, E1-034H)
OOSMFE (b5, E1-032H)