CX28394/28395/28398
Quad/x16/Octal—T1/E1/J1 Framers
2.0 Circuit Description
2.3 System Bus
The status of the offline framer can be monitored using the Offline Framer
Status register [FSTAT; addr 017]. The register reports the following: whether the
offline framer is looking at the receive or transmit data streams (RX/TXN);
whether the framer is actively searching for frame alignment (ACTIVE); whether
the framer found multiple framing candidates (TIMEOUT); whether the framer
found frame sync (FOUND); and whether the framer found no frame alignment
candidates (INVALID).
2.3.5.5 Embedded
Framing
Embedded framing mode [EMBED; addr 0D0] instructs the transmit framer to
search TSLIP buffer output (TNRZ) for framing bits while in T1 mode, or for
MFAS and CAS in E1 mode. Embedded framing allows the transmit timebase to
align with the transmit framer multiframe alignment of the PCM signal
transported across the system bus.
The Embedded mode supports ITU-T Recommendation G.802, which
describes how 24 T1 time slots and framing bit (193 bits) are mapped to the 32 E1
time slots (256 bits): by leaving TS0 and TS16 unassigned; by storing the 24 T1
time slots in TS1 to TS15, and in TS17 to TS25; and by storing the frame bit in
Bit 1 of TS26 (see
100054E
Conexant
2-39
CONEXANT [ CONEXANT SYSTEMS, INC ]
