Texas Instruments PCM1681, Руководство пользователя

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SBAU137 – April 2008
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Demonstration Software
19
Using the Demonstration Software www.ti.com
2.3.1 HOLD and PASS
Near the top of each window, there is a small button. This button is labeled either HOLD or PASS . You
can toggle the current setting by clicking on this button. When set to HOLD, the settings in an active
window can be changed, but are not written to the register(s) until you press the OK button that appears at
the bottom of the screen.
When the button is set to PASS, any setting changes made in an active window are immediately written to
the corresponding register(s).
2.3.2 Applicable Function Control
Table 2-1 summarizes the various functions of the DEM-DAI1681 and the default settings for each
function. Note that the software is also designed to control the DEM-DAI1608 as well as the
DEM-DAI1681; therefore, there are several inconsistencies between the demonstration software and the
PCM1681 register definitions. Table 2-1 also describes these differences between the software of
DEM-DAI1681 and PCM1681 in detail.
Table 2-1. Applicable Function Control Summary
Function PCM1681 Default Setting Availability on DEM-DAI1681
Digital Attenuation Control, 0 dB to –63 dB
in 0.5-dB Steps
0 dB, No Attenuation Applicable
Soft Mute Control Mute Disabled Applicable
DAC1–8 Operation Control DAC1–8 Enabled Applicable
Audio Data Format Control 16-Bit to 24-Bit Left-Justified Partly Applicable
(1)
Digital Filter Roll-Off Control Sharp Roll-Off Applicable
De-Emphasis All Channel Function
Control
De-Emphasis All Channel Disabled Applicable
De-Emphasis All Channel Sample Rate
Selection
44.1 kHz Applicable
Output Phase Select Normal Phase Applicable
Zero Flag Polarity Select High Applicable
Software Reset Control Reset Disabled Not Applicable
Output Phase Select per Channel Reverse Phase Not Applicable
Oversampling Rate Control Narrow (x64, x32, x16) mode Applicable
Digital Filter Roll-Off Control per DATA
Group
Slow Roll-Off Not Applicable
Zero Flag Combination Select ZR1: DATA1 Lch
ZR2: DATA1 Rch
Not Applicable
Digital Attenuation Mode Select 0 to –63 dB, 0.5-dB step Not Applicable
Zero Detect Status
(Read-only, I
2
C Interface Only)
Not Applicable Not Applicable
Function DEM-DAI1681 Default Setting Availability on PCM1681
SCKO Frequency Selection and Output
Enable Control
Enabled as SCKO = SCKI Not Applicable
GPO Output Set and Control Enabled as Zero Flags, not GPOs Not Applicable
Register Read and Address Control Enabled without Auto-Increment Not Applicable
(1)
There is a difference betwen applicable formats and default setting.