WM8978_06 Datasheet, PDF (71/119 Pages) Wolfson Microelectronics plc – Stereo CODEC With Speaker Driver

Pre-Production
WM8978
OUTPUT PHASING
The relative phases of the analogue outputs will depend upon the following factors:
1. DACPOLL and DACPOLR invert bits: Setting these bits to 1 will invert the DAC output.
2. Mixer configuration: The polarity of the signal will depend upon the route through the mixer path.
For example, DACL can be directly input to the OUT3 mixer, giving a 180° phase shift at the OUT3
mixer output. However, if DACL is input to the OUT3 mixer via the left mixer, an additional phase
shift will be introduced, giving 0° phase shift at the OUT3 mixer output.
3. Output boost set-up: When 1.5x boost is enabled on an output, no phase shift occurs. When 1.5x
boost is not enabled, a 180° phase shift occurs.
Figure 28 shows where these phase inversions can occur in the output signal path.
Figure 36 Output Signal Path Phasing
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PP Rev 3.0 May 2006
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