CS62180 datasheet(34/50 Pages) CIRRUS

34 / 50 page

Yellow Alarm

A yellow alarm may be generated on the trans-

mit side by pulling TYEL high. In 193S mode,

bit 2 yellow alarms are supported internally. In

193E mode, FDL yellow alarms are supported.

These formats are also detected by the receiver

and reported on RYEL. Blue alarms are not sup-

ported in hardware mode, except for the

transmission of all "1’s" on TPOS/TNEG during

loopback.

If S-bit yellow alarm is desired while in 193S

mode, it may be externally provided via S-bit in-

sertion, enabled by pulling the 193SI pin high.

There is, however, no way to generate a bit 2

yellow alarm while in 193E mode. Moreover, the

device will not decode either of these formats,

while in hardware mode. If they are required, ex-

ternal alarm detection must be provided.

Zero Suppression

B7 selects the B7 zero suppres-

sion format for the transmitter. Pulling the B7

pin high enables bit 7 stuffing. Pulling the B8ZS

pin high enables B8ZS encoding on the transmit-

ter. The receiver is always capable of decoding

either B8ZS or AMI-encoded data. Transparent

mode may be selected by holding both pins low.

Loopback

Loopback is also provided in the hardware mode

by simultaneously driving the B7 and B8ZS pins

high. The previous state of the pins is main-

tained, and the selected zero suppression mode

remains effective during loopback. While in

loopback, an unframed all "1’s" signal (Blue

alarm) is output on TPOS/TNEG.

CS62180B

DS225PP2

CS62180 Datasheet(PDF) 34 Page - Cirrus Logic