BT8376EPF datasheet(115/323 Pages) CONEXANT

115 / 323 page

Bt8370/8375/8376

2.0 Circuit Description

Fully Integrated T1/E1 Framer and Line Interface

2.11 Loopbacks

N8370DSE

Conexant

2-87

2.11.4 Local Analog Loopback

RLIU provides a local analog loopback to internally route bipolar data from

XTIP/XRING to RTIP/RRING. In the local analog loopback mode, externally

applied data on RTIP/RRING inputs is ignored, and XTIP/XRING output data is

unaffected. The local analog loopback is configured using the ALOOP bit in the

Loopback Configuration register [LOOP; addr 014]. If RCKO is selected as the

TCKI clock source [CMUX; addr 01A], an alternate transmit clock source must

be provided when this loopback is activated. Possible configurations include

selecting the TCKI pin or CLADO as the transmit clock source, or programming

the JAT in the transmit direction and setting JFREE to enable the free-running

10 MHz reference [JAT_CR register; addr 002]. After activating or deactivating

this loopback, the RLIU must be reset using RST_LIU in the LIU Configuration

termination or a transmit termination resistor for local analog loopback to pass

bipolar signals. If no cable and no resistor termination are supplied, then ALOOP

cannot pass bipolar signals to RTIP/RRING.

2.11.5 Local Framer Loopback

The local framer loopback loops the transmit line encoder outputs to the receive

line encoder inputs. The TLIU output is not affected by the activation of this

loopback. The local framer loopback is activated by setting the Local Framer

Loopback (FLOOP) bit in the Loopback Configuration register [LOOP;

addr 014]. If RCKO is selected as the TCKI clock source [CMUX; addr 01A],

then an alternate transmit clock source must be provided when this loopback is

activated. Possible configurations include selecting the TCKI pin or CLADO as

the transmit clock source, or programming the JAT in the transmit direction and

setting JFREE to enable the free running 10 MHz reference [JAT_CR register;

addr 002]. It is possible to operate the local framer loopback simultaneously with

the remote line loopback. If transmit jitter attenuator is also enabled, TJAT is

placed in the framer loopback path. RJAT, if enabled, is not present in the framer

loopback path.

2.11.6 Local Per-Channel Loopback

The local per-channel loopback loops the TSB PCM and signaling inputs to the

RSB PCM and signaling outputs on a per-channel basis. The local per-channel

PCM loopback is activated by setting RLOOP in the System Bus Per-Channel

Control registers [SBC0 to SBC31; addr 0E0 to 0FF]. The local per-channel

signaling loopback is activated by setting SIG_LP in System Bus Per-Channel

Control registers.

BT8376EPF Datasheet(PDF) 115 Page - Synaptics Incorporated.

BT8376EPF Datasheet(HTML) 115 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