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Type: Posts; User: Neal

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  1. Replies
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    Has this reverb code been merged into the Audio...

    Has this reverb code been merged into the Audio Library yet?

    Also where can I find the source code for audio library 1.54-beta7?

    Thanks
  2. Are you still hearing the "freeverb buzzing and...

    Are you still hearing the "freeverb buzzing and crackling noises" you mentioned in post #21? Did you ever try the floating point version post #16?
  3. Did anyone have any success getting the floating...

    Did anyone have any success getting the floating point version above (dirkenstein) working either in Audio library form or in standalone mode?
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    I see. Also neat the way tail chaining minimizes...

    I see. Also neat the way tail chaining minimizes the pushing/popping time. Nice stuff.

    Is there a document that describes the interrupt in more detail than the Document Number: IMXRT1060RM Rev. 2,...
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    Thanks for the responses. I realize that the...

    Thanks for the responses. I realize that the interrupt code in a real application should be as short as possible. My example was constructed to help understand the timer interrupt process.

    Also,...
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    Teensy 4.1 IntervalTimer Interrupt

    My question: Once an interrupt is setup using the IntervalTimer class in the teensy core, when does the actual interrupt get reenabled. In my application it looks like the interrupt routine isn't...
  7. Your right. So the modification to the library...

    Your right. So the modification to the library would have to be more extensive than I said. It make more sense to bypass the Audio library FFT and do the FFT separately.
  8. The arm_cfft_radix4_q15(&fft_inst, buffer) ...

    The arm_cfft_radix4_q15(&fft_inst, buffer) function output is located in the buffer[] in the form real, complex, real, complex......
    The for loop you show in your code snippet converts that to...
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    I am running my project at 96000 Hz. Before I...

    I am running my project at 96000 Hz. Before I proceed I want to check an assumption I am making.

    If, for example, I run the four stage ladder filter AudioFilterLadder::update() at a 88000 Hz...
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    The sketches on my windows 10 machine are located...

    The sketches on my windows 10 machine are located in {Documents}/Arduino/libraries. That is where I put it. The compiler said it found two Audio.h files and it automatically chose the original...
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    I want to experiment with the Audio Library...

    I want to experiment with the Audio Library version of this filter. As suggested by Paul in message #50 of this thread, I downloaded a zip version of https://github.com/PaulStoffregen/Audio and...
  12. Sorry, I just noticed two omissions. Here is the...

    Sorry, I just noticed two omissions. Here is the code with a few added lines:


    #ifndef PLATFORM_H
    #define PLATFORM_H
    #include <Arduino.h>
    #include <Audio.h>

    #define...
  13. Here is the code pieces I used to get at the...

    Here is the code pieces I used to get at the sgtl5000 registers so I could mute the DACs separately. It uses the codec library without changes.


    #ifndef PLATFORM_H
    #define PLATFORM_H
    #include...
  14. The library does not need to be changed to be...

    The library does not need to be changed to be able to modify the various sgtl5000 registers. Since the read, write and modify methods are designated "protected" and not "private" in the library, they...
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    I don't see any information re: the sgtl5000...

    I don't see any information re: the sgtl5000 having antialiasing filters on the ADC inputs. I may be missing something???

    Thanks
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    I got my replacement Audio board running and...

    I got my replacement Audio board running and reran my tests. I reconfirmed that Paul's observations are accurate in my test setup as well. The ADC transmits 24bits regardless of the CHIP_I2S_CTRL...
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    Thanks for the responses. Paul I did the same...

    Thanks for the responses. Paul I did the same test you did with two exceptions. I bypassed the line in and line out series capacitors and fed in a very clean DC signal into the ADC and measured the...
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    Yes I realize that the it is only spec'd to 96...

    Yes I realize that the it is only spec'd to 96 kHz. I guess I was hoping there was some magical overdrive mode.

    The real dilemma I am having is that it appears the sgtl5000 ADC outputs 32 bits and...
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    sgtl5000 32 bit ADC and DAC

    In my application, everything I am using 32 bit integers exclusively. I would like to use the 32 bit mode in the sgtl5000 as well.

    As far as I can tell the following lines of code from the i2s...
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    Can you point me to a TI audio codec similar to...

    Can you point me to a TI audio codec similar to the sgtl5000 that has more information on the decimation and reconstruction filters?
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    I finally found a bit of time to dig into this a...

    I finally found a bit of time to dig into this a little further. I wanted to find out how much of the 250 usec could be attributed to just the DAC. So I measured the time it took from an i2s write to...
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    The total delay is 250 usec when input and output...

    The total delay is 250 usec when input and output are viewed on an oscilloscope. Since the sampling frequency is 96000 Hz, that is about 24 sample times. This is basically a black box test, so I have...
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    As a point of reference, the 250 usec delay I...

    As a point of reference, the 250 usec delay I measured in my testing is about 24 sample delays because my test was at Fs = 96000 Hz. It is an 11 sample delay at Fs = 44100.

    The TI document is well...
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    Here is a much better explanation than the one I...

    Here is a much better explanation than the one I gave.

    https://web.ece.ucsb.edu/~yoga/courses/DSP/P10_Linear_phase_FIR.pdf
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    No, I mean linear phase delay. For example, if...

    No, I mean linear phase delay. For example, if you have a signal that is made up of say a 1 Hz tone and a 2 Hz tone and you are going to feed them into a linear phase FIR filter. Both signal...
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    I did more tests over the past few days and the...

    I did more tests over the past few days and the results are consistent with the above assumptions of there being a FIR filter somewhere in the processing chain. I tested the delays over for various...
  27. Your post is a few months old, but I have two...

    Your post is a few months old, but I have two questions:
    1. Can you point me to a link that documents the -Wl,--print-memory-usage option?
    2. How did the output it generated compare to the output...
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    Yes I agree the architecture is probably sigma...

    Yes I agree the architecture is probably sigma delta. Also, at a 10.4 usec conversion rate, the delay is about 25 sample times. FIRs can eat that up, but IIR CIC filters that are usually used after a...
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    sgtl5000 Delay from ADC to DAC

    I wrote a simple program to try and understand a 250 usec delay I am seeing between the sgtl5000 input to its output. The intent of this test is to take a single sample from the codec ADC into the...
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    Thanks for taking care of that. Good solution.

    Thanks for taking care of that. Good solution.
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    I don't think it is necessary to change any...

    I don't think it is necessary to change any source code. It would be nice to include it in errata documentation somewhere if an errata exists.

    I just reversed things in my project code. I pointed...
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    sgtl5000 ADC lineInLevel() Gain Control

    FYI-Here is a very small item that caused me some confusion while using the sgtl5000 Audio Library routines. I did not find it mentioned anywhere in the forum so I thought I would document it for...
  33. Frank-My uP is a T4.1 and the Memory wipe...

    Frank-My uP is a T4.1 and the Memory wipe procedure shown on the teensy 4.1 page solved the problem.

    Memory Wipe & LED Blink Restore
    Teensy 4.1 will fully erase its non-volatile memory and return...
  34. I wanted to play with this a bit so I temporarily...

    I wanted to play with this a bit so I temporarily added this line of code into the main loop():

    if(digitalReadFast(29) == LOW) SCB_AIRCR = 0x05FA0004;

    Now, even with removing that line of code...
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    Teensy 4.1 ON/OFF Pin Access/Use

    "On / Off Pin and Power Control" is mentioned at https://www.pjrc.com/store/teensy41.html. Is there a pad somewhere on the Teensy 4.1 PCB to access the ON/OFF connection to the microprocessor? I...
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    dbuergin-Would you please help me understand why...

    dbuergin-Would you please help me understand why the _DSB() is needed here. I know it inserts and asm dsb but not sure why needed. I am not very assembly language savvy.

    I am also having trouble...
  37. Thread: Audio filter

    by Neal
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    Here is a fairly long example using biquads that...

    Here is a fairly long example using biquads that I think has what you want. It uses multistage biquads.



    /*
    -Sept 23 '19 Added code to modify the MODULATION_PITCH_COEFFICIENT (initial and...
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    Not sure what you are asking for. The code in #4...

    Not sure what you are asking for. The code in #4 above is the code required to set up the i2s communication with the audio adapter board. It configures the is2 port and the example sends a simple...
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    ericfont-the attachment method you used didn't...

    ericfont-the attachment method you used didn't work. Would you please possibly include the link to the other product's app note.
    Thanks
  40. KurtE, thanks for the explanation of what the...

    KurtE, thanks for the explanation of what the arm_dcache_flush() and arm_dcache_delete() methods do. I have seen them used in various places in the Audio Library and I wasn't sure what they did. I...
  41. Can DMA to i2s Data Transfer Get Corrupted by a Write to Source Location

    I am working with a Teensy 4.1 and the Audio Adapter. I extracted some code from the Audio Library output_i2s to do some direct writing to the sgtl5000 DAC. Here is the begin function I am using:
    ...
  42. Wow! That is very helpful. Thanks Paul Neal

    Wow! That is very helpful. Thanks Paul

    Neal
  43. i.MX RT1050 Reference Manual, Rev. 1, 03/2018 in imxrt.h

    I am using the Teensy 4.1 and the imxrt.h for device specific register information. At the beginning of the imxrt.h file is a rference to the i.MX RT1050 Reference Manual. Throughout the imxrt.h...
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    To answer my own question in my last post, I had...

    To answer my own question in my last post, I had to add a data cache management functions must be used to flush cached data after data after each output to the CODEC. The function I used I saw in the...
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    Paul, both excellent suggestions. I left the SOFF...

    Paul, both excellent suggestions. I left the SOFF and SLAST that way in case I wanted to use a larger buffer later. I left the completion interrupt in so I could monitor that things were running by...
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    Thanks for the replies. I think I should have...

    Thanks for the replies. I think I should have explained better what I am doing better in my original post. I got something working last night that I will include for others to view.

    My goal is to...
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    Writing Directly to SGTL5000 CODEC DACs

    I am new to the forum and in my application I am using a Teensy4.1 with the Audio Shield and attempting to do some digital signal processing for a class I am teaching.

    Has anyone come up with a...
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