BT8376EPF datasheet(53/323 Pages) CONEXANT

53 / 323 page

Bt8370/8375/8376

2.0 Circuit Description

Fully Integrated T1/E1 Framer and Line Interface

2.4 Receiver

N8370DSE

Conexant

2-25

The offline framer is shared between the RCVR and XMTR and can search in

only one direction at any time. Consequently, the processor arbitrates which

direction is searched by enabling the reframe request (RLOF and TLOF) for that

direction.

The offline framer waits until the current search is complete (see [FSTAT; addr

017]) before checking for pending LOF reframe requests. If both online framers

have pending reframe requests, the offline framer aligns to the direction opposite

from that which was most recently searched. For example, if TLOF is pending at

the conclusion of a receive search which timed out without finding alignment, the

offline framer switches to search in the transmit direction. The TLOF switchover

is prevented in the preceding example if the processor asserts TABORT to mask

the transmit reframe request. TABORT does not affect TLOF status reporting. For

applications that frame in only 1 direction, the opposite direction should be

masked. If, at the conclusion of a receive search, TLOF status is asserted but

masked by TABORT, the offline framer continues to search in the receive

direction. For applications that frame in both directions, the processor can allow

the offline framer to automatically arbitrate among pending reframe requests, or

can elect to manually control reframe precedence. An example of manual control

follows:

The status of the offline framer can be monitored for diagnostic purposes

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 a frame alignment (ACTIVE)

•

whether the framer found multiple framing candidates (TIMEOUT)

•

whether the framer found frame sync (FOUND)

•

whether the framer found no frame alignment candidates (INVALID)

NOTE:

These status bits are updated in real time and might be active for only very

short (1-bit) periods of time.

Initialize RABORT = 1 and TABORT = 1

Enable RLOF and TLOF interrupts

Read clear pending ISR interrupts

Release RABORT = 0

Call LOF Service Routine if either RLOF or TLOF interrupt;

{

(check current LOF status [ALM1, 2; addr 047, 048]

If RLOF recovered and TLOF lost

—Assert RABORT = 1

—Release TABORT = 0

If RLOF lost or TLOF recovered

—Assert TABORT = 1

—Release RABORT = 0

}

BT8376EPF Datasheet(PDF) 53 Page - Synaptics Incorporated.

BT8376EPF Datasheet(HTML) 53 Page - Synaptics Incorporated.

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL