3.0 Registers
Bt8370/8375/8376
3.6 Primary Control and Status Registers
Fully Integrated T1/E1 Framer and Line Interface
FOUND
Frame Search Successful—Active-high indicates the offline framer located the frame
alignment according to the selected receive or transmit framer mode. Refer to Table 3-5 for
maximum 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
• the offline framer goes inactive, if no pending reframe requests exist
• the RX, TX, or TSB timebase is realigned, depending on the 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]
increments. Changes of the transmit frame alignment are not detected.
NOTE:
In E1 receive framer modes, the offline framer also reports intermediate FRED,
MRED, and SRED status [ALM3; addr 049] while searching for FAS, MFAS, and
CAS alignment, respectively.
0 = no candidate; search active, aborted, or timed out
1 = frame alignment found (1 and only 1 candidate)
Table 3-5. Maximum Average Reframe Time (MART) and Framer Timeout
Framer Mode
MART
TIMEOUT (addr 017)
Ft
Ft + T1DM
SF
3.5 ms
1.0 ms
3.5 ms
4.5 ms
2.0 ms
15.0 ms
10.0 ms
15.0 ms
15.0 ms
0.5 ms
2.0 ms
10.0 ms
12 ms ±1 bit
12 ms ±1 bit
12 ms ±1 bit
12 ms ±1 bit
12 ms ±1 bit
24 ms ±1 bit
24 ms ±1 bit
24 ms ±1 bit
24 ms ±1 bit
8 ms ±125 µs
8 ms ±125 µs
8 ms ±125 µs
SF + JYEL
SF + TIDM
SLC
ESF
ESF + CRC
ESF + MIMIC
FAS
CAS
MFAS
NOTE(S): MART is defined (per Bellcore TA-0278) as the difference between the time that
known good pseudo-random DS1 input is applied, and the time that a valid DS0 signal is
observed at the output.
3-30
Conexant
N8370DSE
CONEXANT [ CONEXANT SYSTEMS, INC ]
