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ADAU1701 Volume Control Using MCU

Question asked by dan_xerx on Dec 17, 2013
Latest reply on Dec 22, 2013 by dan_xerx

Hello Bob!


I just need to ask about volume control using 8bit MCU as a master to control the sigma DSP ADAU1701 volume using push buttons Everytime i push either Volume UP/DOWN, the MCU writes to the appropriate DSP param address. I have problems implementing it in software. How do you do it?  In my understanding, you READ first, then increment/decrement by a fixed value, then WRITE the new 4 byte data to the param address. Is this correct? If possible can you give me some sample to code to manipulate such data to get the correct value and write it to the DSP address?


Using volume control no slew:


Gain(dB)                Value                                Data

     0                         1                       0x00 0x80 0x00 0x00

    -2                    0.7940                    0x00 0x65 0xAC 0x8C   

    -4                    0.6309                    0x00, 0x50, 0xC3, 0x36

    -6                    0.5011                    0x00, 0x40, 0x26, 0xE7

     .                         .                                        .

     .                         .                                        .

     .                         .                                        .

     .                         .                                        .

I found it confusing how I can get the current value and get a correct incremented value afterwards when I want some volume change. I have tried to program it by myself but I cannot get the correct value, as displayed by the logic analyzer.



Regards & Thanks