cx28394 Conexant Systems, Inc., cx28394 Datasheet - Page 151

• Manufacturer Part Number: cx28394
• Description: Quad/x16/octal-t1/e1/j1 Framers
• Manufacturer: Conexant Systems, Inc.

CX28394/28395/28398
Quad/x16/Octal—T1/E1/J1 Framers
DL3_BIT[7:0]
Each framer contains a single offline framer that acts as a shared resource for both receive and transmit
channels. Current alignment status for receive and transmit channels are reported separately in Alarm Status
Registers (ALM1, ALM2; addr 047, 048). FSTAT is thus used primarily for diagnostic purposes to monitor the
progress of an alignment search or to verify acknowledgment of a processor-generated forced reframe request.
These status bits may only be reported for a very short period of time (i.e., 1 clock cycle) since the RLOF and
TLOF reframe requests may immediately request another offline framer search.
INVALID
FOUND
100054E
016—External Data Link Bit (DL3_BIT)
017—Offline Framer Status (FSTAT)
DL3_BIT[7]
—
7
7
DL3_BIT[6]
External Data Link Bit Select—Enables receive (RDLCKO) and transmit (TDLCKO) clock
pulse outputs during the selected time slot bits. DL3_BIT and the DL3_TS Register [addr 015]
select any combination of bits for input and output on the external data link pins by writing the
corresponding DL3_BIT active (high). LSB enables clock pulses coincident with the first bit
transmitted or received. Full T1/E1 data stream is output on RDLO as long as the RDL_IO bit
[addr 018] is active and regardless of which bits are accompanied by RDLCKO clock pulses.
The selected transmit data link bits are sampled from the TDLI pin on the falling edge of
TDLCKO to replace normal transmitted data. DL3_BIT has no effect when DL3_TS selects
T1 Fbits or when the DL3EN bit is inactive. DL3 is not accessible on the CX28395 device.
No Candidate—Active high at the conclusion of a search during which no frame alignment
candidates were located.
Frame Search Successful—Active high indicates the offline framer located frame alignment
according to the selected receive or transmit framer mode. Refer to
Average Reframe Time. Upon detection of frame alignment, the following occurs: FOUND
goes active high, RLOF or TLOF is cleared by the online framer (depending on RX/TX
direction), offline framer goes inactive (if no pending reframe requests), and RX, TX, or TSB
timebase is realigned (depending on RX/TX direction and the embedded framing mode). If the
reframe pulse causes the receive timebase to align to a position that differs from its existing
alignment, the change of frame alignment error counter [COFA; addr 05A] will increment.
Changes of the transmit frame alignment are not detected.
NOTE:
—
0 = disable DL3 bit
1 = enable DL3 bit
0 = search active, aborted, timed out, or found
1 = alignment not found (no candidate)
0 = no candidate: search active, aborted, or timed out
1 = frame alignment found (one and only one candidate)
6
6
In E1 receive framer modes, the offline framer also reports intermediate FRED,
MRED, and SRED status [ALM3; addr 049] while searching for FAS/MFAS/CAS
alignment, respectively.
DL3_BIT[5]
—
5
5
DL3_BIT[4]
INVALID
4
4
Conexant
DL3_BIT[3]
FOUND
3
3
DL3_BIT[2]
TIMEOUT
3.7 Primary Control and Status Registers
2
2
Table 3-8
DL3_BIT[1]
ACTIVE
1
1
for Maximum
3.0 Registers
DL3_BIT[0]
RX/TXN
0
0
3-29