AN1250 STMicroelectronics, AN1250 Datasheet - Page 19

• Manufacturer Part Number: AN1250
• Description: STA014/STA015 MPEG LAYER III DECODER AND ADPCM CODEC
• Manufacturer: STMicroelectronics

Note: 1. 32KHz stereo encoding is only available in DVI ADPCM mode, as stated on the datasheet.
§8.7 WOW (SRS Labs.) Page
The STA014T control panel also includes an additional page dedicated to the WOW post-processing feature
controls. As shown in the Figure 18 the available controls allow to set the WOW and TrueBass enhancement
level and the speaker type (large, medium or relative to headphones). Of course this controls will be effective
only if the WOW post-processing feature has been turned on.
Figure 18. WOW page
9. PLL CONFIGURATION
9.1 PLL Overview
All the internal reference clocks required to operate the device and to output decoded audio samples are gen-
erated using the embedded digital PLL block. Depending on the external reference clock used (typically coming
from en external crystal) some PLL registers must be initialized after device power-on: after that the DSP firm-
ware is able to automatically decode any MPEG bitstream with any sample rate or bitrate without further con-
figuration or initialization. The output I2S clocks (LRCKT and SCKT) will be automatically tuned according to the
decoded MPEG bitstream: if the ADPCM mode is enabled the output frequency will depend on the choosed
sample rate.
9.2 PLL Configuration Utility
In order to make the PLL configuration task as easy as possible a small software utility is available. As shown
in Figure 19 no technical skills are required to operate the software. Only two input data are required to compute
PLL register values:
XTI Frequency: this is the external reference frequency (tipically coming from a crystal device). A wide
range of values can be used with no loss in decoder performance (suggested values are between 8
MHz and 24 MHz)
AN1250 APPLICATION NOTE
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