Tripath Technology, Inc. – Preliminary Technical Information

22

TCD6000 – Rev. 1.0/09.04

The Soft-Mute function will turn off volume selectively on any of the 6 channels. Setting control bits M1

through M6 to ‘1’ will issue a Soft-Mute on the corresponding channels. If the VRE bit in the Volume Change

Control Register is set, the volume will first ramp down at a rate defined by the Volume Ramp Rate Register.

Soft-Mute has no affect on whether the differential outputs (Y1 and Y1B through Y6 and Y6B) continue to

switch or not. Clearing bits M1 through M6 to ‘0’ will re-establish volume on all channels at a rate defined by

the Volume Ramp Enable settings.

The Hard-Mute function is enabled by setting control bit HM high. This function starts with a Soft-Mute on all

channels simultaneously. If the VRE bit in the Volume Change Control Register is set, the volume will first

ramp down at a rate defined by the Volume Ramp Rate Register. Once volume is turned off on all channels,

all differential outputs (Y1 and Y1B through Y6 and Y6B) stop switching. This will reduce power consumption

in the power stages driven by the TCD6000.

When control bit HM is cleared to ‘0’, the Hard-Mute condition is removed, and the TCD6000 goes through

an automatic DC calibration cycle. Once the calibration cycle is complete, volume is re-established on all

channels at a rate defined by the Volume Ramp Enable settings.

The Auto-Mute function is enabled by setting the AM bit to ‘1’. This function detects digital silence (all data

input bits at 0) on all 6 channels lasting more than a pre-defined delay. It then issues a Hard-Mute. The

delay is determined by the contents of the Auto-Mute Timing Register (described below). Upon arrival of

non-zero data on any channel, the Hard-Mute condition is automatically removed. The volume on all 6

channels is re-established at a rate defined by the Volume Ramp Enable settings. The Auto-Mute function

reduces power consumption in the power stages during periods of silence.

Auto-Mute Timing

Addr

Register Name

D7

D6

D5

D4

D3

D2

D1

D0

2Dh

Auto-Mute Timing

AM7

AM6

AM5

AM4

AM3

AM2

AM1

AM0

Default

0

0

0

0

0

0

0

0

This register is only used if the Auto-Mute function is enabled. Its contents specify the duration of silence on

all 6 channels before a Hard-Mute condition is issued. If the number entered is “N”, the duration of silence is

equal to:

(2N + 1) x (1,048,576 periods of LRCK)

As an example, if N = 1 and the period of LRCK is 22.67usec, the period of silence required before a Hard-

Mute condition is issued is:

3 x 1,048,576 x 22.67usec = 71.3 seconds