CS61305A データシートの表示（PDF） - Cirrus Logic

部品番号

コンポーネント説明

メーカー

CS61305A

T1/E1 Line Interface

Cirrus Logic 

CS61305A

Local Loopback

Local loopback is selected by taking LLOOP, pin

27, high or by setting the LLOOP register bit via

the serial interface.

The local loopback mode takes clock and data

presented on TCLK, TPOS, and TNEG (or

TDATA), and outputs it at RCLK, RPOS and

RNEG (or RDATA). Inputs to the transmitter are

still transmitted on TTIP and TRING, unless

TAOS has been selected in which case, AMI-

coded continuous ones are transmitted at the

TCLK frequency. The receiver RTIP and RRING

inputs are ignored when local loopback is in ef-

fect. The jitter attenuator is not in the local loop

back path.

Remote Loopback

Remote loopback is selected by taking RLOOP,

pin 26, high or by setting the RLOOP register bit

via the serial interface.

In remote loopback, the recovered clock and data

input on RTIP and RRING are sent through the

jitter attenuator and back out on the line via TTIP

and TRING. Selecting remote loopback overrides

any TAOS request (see Table 7). The recovered

RLOOP TAOS Source of

Input Input

Data for

Signal Signal TTIP & TRING

Source of

Clock for

TTIP & TRING

0

0

TDATA

TCLK

0

1

all 1s

TCLK

1

X RTIP & RRING RTIP & RRING (RCLK)

Notes: 1. X = Don’t Care. The identified All Ones Select

input is ignored when the indicated loopback is

in effect.

2. Logic 1 indicates that Loopback or All Ones

option is selected.

Table 7. Interaction of RLOOP with TAOS

incoming signals are also sent to RCLK, RPOS

and RNEG (or RDATA). A remote loopback oc-

curs in response to RLOOP going high.

Simultaneous selection of local and remote loop-

back modes is not valid (see Reset).

In the Extended Hardware Mode the transmitted

data is looped before the AMI/B8ZS/HDB3 en-

coder/decoder during remote loopback so that the

transmitted signal matches the received signal,

even in the presence of received bipolar viola-

tions. Data output on RDATA is decoded,

however, if RCODE is low.

Driver Performance Monitor

To aid in early detection and easy isolation of

non-functioning links, the IC is able to monitor

transmit drive performance and report when the

driver is no longer operational. This feature can

be used to monitor either the device’s perform-

ance or the performance of a neighboring driver.

The driver performance monitor indicator is nor-

mally low, and goes high upon detecting a driver

failure.

The driver performance monitor consists of an ac-

tivity detector that monitors the transmitted signal

when MTIP is connected to TTIP and MRING is

connected to TRING. DPM will go high if the

absolute difference between MTIP and MRING

does not transition above or below a threshold

level within a time-out period. In the Host Mode,

DPM is available from both the register and pin

11.

Whenever more than one line interface IC resides

on the same circuit board, the effectiveness of the

driver performance monitor can be maximized by

having each IC monitor performance of a neigh-

boring IC, rather than having it monitor its own

performance.

DS157PP3

15

Share Link: