ADAU1701 State detection

I can read the input size of label 3 in the MCU. Why ca n’t I read the input size of label 1 and label 2?

  • +1
    •  Analog Employees 
    on Jan 13, 2020 4:14 PM 10 months ago

    Hello Evin,

    The level is probably really low so you are not seeing it on the readback. The readback hardware on this DSP is limited to 24 bits. Internally in the DSP there are 28 bits. The bottom four bits are truncated and not shown by the readback cell. Many times this is fine, the bottom bits are not important but there are many times where you need to see them. So in those instances you need to multiply the data by 16. This will truncate the upper four bits but give you the lower bits in the readback cell. 

    The screenshot below is from a program where you want to see an index value on an index controlled cell. It is an integer value so you need to see the bottom bits. 

    Note that two gain cells are used because you cannot enter a 16 as a whole number in a 5.19 fixed point number format. 15 is the highest so you get around that by multiplying by 4 twice. 

    On another note, you will not need to use the absolute value cells after the envelope generators. The code in the envelope generators already do that for you in the process of generating an envelope of the signal level. It will always be a positive number. 

    Dave T

  • Hi Dave,

    Thank you very much for your answer, your answer was very helpful to me.