ADAU1702 internal DAC How to Output DC signal?
ADAU1702
1> How to let internal DAC output the desired DC voltage from I2C ：For example, how to output 1V, or 2V DC,
What modules do we need and what kind of values do we need to fill in to output 2v ?
2>In addition, we want to drive a UV pointer with DC output to indecate current RMS
In Log lookup table, what range of data do we need to fill in to enable DC to output DC signals?
Audio Signal Processors
adau1702
SigmaDSP Audio Processors
Hello cassini,
In your SigmaStudio project, have a DC Source feed the DAC input. Then after compiling your project, observe the Capture Window to see the safeload address and data to send by I2C. Below I tried several DC Source values with the results shown:
At the DAC output pin you really need a reconstruction filter like those shown in the ADAU1701 data sheet (of course omit the DC blocking cap):
To see how well these DACs work with DC levels, experiment with the project shown at
ADAU1701 DAC DC voltage
-- To make the volume pot linear, right-click its knob.
The ADAU1701-2 is primarily for audio applications, thus its ADCs and DACs aren't perfect at DC. Where I work we have found that:
Full-scale output (DAC input -1.0) varies with Vcc, so use a well-regulated supply
Minimum output (DAC input +1.0) varies a little from chip to chip. You can devise an auto-calibration scheme where you measure the DAC output with +1.0 input, then subtract this result from subsequent readings.
This post may help you with the Log Lookup Table:
Is there any documentation for the ADAU170x's Log Lookup Table?
Best regards,
Bob
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