Tripath Technology, Inc. – Preliminary Technical Information
Bits VR1
VR0
0
0
1
1
0
1
0
1
1X volume
2X volume
4X volume
8X volume
The VRE control bit is the Volume Ramp Enable bit. If VRE = ‘1’, the contents of the Volume Ramp Rate
Register will be read and determine how fast the volume can ramp up or down on all 6 channels. Refer to
the Volume Ramp Rate Register section for a more detailed explanation of how the ramp rate is calculated.
The ZCE control bit is the Zero-Crossing Enable bit. A polarity inversion on the audio input signal is called a
“Zero-Crossing”. Changing volume only at Zero-Crossings helps to avoid popping sounds. If ZCE is set to
‘1’, volume will only be allowed to change at Zero-Crossings. However, if a Zero-Crossing does not occur
within a time defined by the Volume Ramp Rate Register (called “time-out” in the graph below), volume will
change anyway. If the Zero-Crossing feature is enabled, the VRE control bit will still control whether the
volume change occurs in one large step or in 1/8 dB steps at Zero-Crossings.
Volume change occurs at every
zero-crossing
Audio signal
Amplitude
Time
No zero-crossing, volume change
occurs after time-out
time-out
27
TCD6001 – JL/Rev. 0.9/07.05
TRIPATH [ TRIPATH TECHNOLOGY INC. ]
