Search results

  1. A

    Dynamic Range Compressor new class library. I wish to share.

    Recently I bought 4 x Teensy 4. But........ the hardware I have built into my PA system is based on the 3.2. It is a royal PITA to retrofit the 4. It is in my plan, but at the same time I am also planning to upgrade the AD and DA devices as the SGTL5000 is quite noisy. Anyway, instead of a retro...
  2. A

    Dynamic Range Compressor new class library. I wish to share.

    I would like to point out that because the compressor works in the Log domain and to try and avoid excessive floating point operations. I have used LUTs to convert from linear to Log and also Log to linear. These require about 20K of program memory. I tried very hard to minimise this footprint...
  3. A

    Dynamic Range Compressor new class library. I wish to share.

    Okay dokay, Should be attached. Aidan
  4. A

    Dynamic Range Compressor new class library. I wish to share.

    Hi, I have just created a new class library for the Audio Library (a new audio object) as the pjrc web page describes it. I'm not sure which is the correct terminology. Anyway. I have a fully functional .cpp and .h file which follows the guidelines as described and works very well. I have been...
  5. A

    Distributed DSP and I2S TDM

    Thank you and apologies. I certainly went off a bit half-cock. Now that I actually downloaded the correct reference manual for the Teensy 4.0 uC what I say MIGHT make more sense. And, yes, I am stuck in Teensy 3.2 mode. I do not yet have a Teensy 4.0. I have been determinedly trying to squeeze...
  6. A

    Distributed DSP and I2S TDM

    Technically speaking, I think it is only because the Teensy Audio library is based around 16bit depth per channel that the TDM object has a total of 16 channel. If I am not mistaken a single I2S data line running in TDM fs256 mode can carry a total of 8x32bit channels. Inside the Teensy Audio...
  7. A

    Distributed DSP and I2S TDM

    Hi, I am planning a new audio project using Teensy 4.0. This requires a significant number of ADC inputs coming from different ADCs. The intention is to have a central uC used to drive a UI via touchscreen and this device will also handle all outbound (i.e to DAC) DSP work. Postprocessing...
  8. A

    Freeverb - faster code base for Teensy 3.2 using SIMD

    Woops, spotted a fundamental flaw, .... asm volatile ( "QADD %[SUM], %[C1], %[C2]\n" "QADD %[SUM], %[C3], %[SUM]\n" "QADD %[SUM], %[C4], %[SUM]\n" "QADD %[SUM], %[C5], %[SUM]\n" "QADD %[SUM], %[C6], %[SUM]\n" "QADD %[SUM], %[C7], %[SUM]\n" "QADD %[SUM], %[C8], %[SUM]\n"...
  9. A

    Teensy Audio Shield PCB layout and SGTL library oversampling?

    Hi, I have been working on a small project using the SGTL5000 on the audio shield, in fact I have used the same board before with other projects and faced the same issues. It is one of noise. I realise that the SGTL5000 does not have world beating SNR figures on its ADC inputs but I have tried...
  10. A

    Freeverb - faster code base for Teensy 3.2 using SIMD

    Hi, well I don't imagine that this is the best approach. In fact I am very much a newby to the Teensy Arduino environment. I am a little frustrated as I was not, at the time I made these changes, aware of the fact that there are a bunch of intrinsic functions within the Audio library that cover...
  11. A

    Glitching sound samples with movement | Teensy 3.2 | NEED HELP <3

    I'm quite confident that if you found the correct loudspeaker you would not need a separate amplifier. Speakers can be a little confusing. In your case it is not about earth shattering power Handling. This is the figure they are quoting when they say "Its a 2W speaker" etc. This is how much...
  12. A

    Glitching sound samples with movement | Teensy 3.2 | NEED HELP <3

    Hi Tim, As Frank B already alluded to, your primary concern is that of storage space. To put some figures around this if you use uncompressed PCM (.wav digital sound files) then at 8bit resolution and running at 8Khz sampling frequency you will be able to store~ 30sec of sound data on a Teensy...
  13. A

    Freeverb - faster code base for Teensy 3.2 using SIMD

    Hi all, I'm sharing this library modification with all, in the hope some may find it useful. I noted that whilst developing a little project of mine that the freeverb effect was limited to the single channel option when running on a Teensy 3.2. I needed two independent channels and I only had a...
  14. A

    Support for Teensy within Mbed RTOS

    Thanks, your suggestions are appreciated. I took a look at the various editors you mentioned, and I'm still making a decision about which way I might turn. In fact I have been trying to get the Teensy 3.2 up and running in Mbed Studio. Requires a whole new set of drivers, which I have not yet...
  15. A

    Support for Teensy within Mbed RTOS

    Hi, I have asked a similar question in the past and would like to clarify what is the current situation. I have developed in the past using Mbed online IDE where support was and still is available for the Teensy 3 platform. Mbed have now released a stand alone IDE (Mbed Studio), to complement...
  16. A

    Teensy 4.x future support on MCU and Cirrus Logic codec

    Thanks Paul, That's really good news. I'm planning on trying to use the 'Faust' libraries with this codec and after experience with the T3.2, I'm pretty sure I will run out of steam with multiple algorithms running on multiple channels. But as usual you are already well ahead of my game. I look...
  17. A

    Teensy 4.x future support on MCU and Cirrus Logic codec

    I think perhaps I am overstating this and I apologise if that is excessive. Indeed "Not recommended for new designs. No discontinuance decision has been made" So bad sorry, however it just seems to be this particular variant, others in the same family seems normal. Okay I'm comfortable and...
  18. A

    Teensy 4.x future support on MCU and Cirrus Logic codec

    Hi, I have been using Teensy 3.2 for previous projects but wanted a little more horse power,....so Teensy 4.x. However I noticed that the MCU has been EOL by NXP. Is this going to have any significant impact on the product in the future, is there a path forward for this board? Also, I am...
  19. A

    Access to all 3 I2S modules on Teensy 4.0

    Hi, A quick questions. I see from the user manual of the NXP chip used on the Teensy4 that it actually has 3 I2S modules. The specs for the Teensy 4.0 states only 2 I2S are broken out. I assume that if desired the MCU internal mux can be re-programmed to allow access to all three I2S modules...
  20. A

    Anti Alias filters on SGTL5000

    Hi, I never truly solved it. Every step I took made subtle improvements but in the end I came to the conclusion that it is what it is. The CODEC itself does not have exactly hi-fi quality datasheet specs. 85dB SNR. I suppose this is quoted under ideal conditions, but its not great. Indeed if you...
  21. A

    Anti Alias filters on SGTL5000

    Paul, I thought I would let you know a couple of things. Regarding the noisy SGTL5000. I did find a little something, quite interesting. The CODEC has a debug register, one of the options is to disable dithering. This is enabled by default. Hey presto, full resolution. Hmmm, well, I don't...
  22. A

    Can the Teensy 3.0 be programmed without pressing the button?

    A little follow up on this suggestion. Firstly it does not work simply by tieing the GPIO pin from K20 onto the program pin. The K20 only manages to assert LOW for 100uS. It is not long enough, this causes the RESET_B to be triggered and the running code stops. However the bootloader does not...
  23. A

    Anti Alias filters on SGTL5000

    Hi Paul et al, Just wanted to let you know. I have totally re-written my driver library for the mbed platform. It now uses DMA. Much better I feel. I have published it and it is available here: https://developer.mbed.org/users/aidan1971/code/SGTL5000/ Also supporting 192Kb/s. Though even so...
  24. A

    Anti Alias filters on SGTL5000

    I just wanted to add, there seems also to be rather obvious problems with channel separation with the SGTL5000. I was hoping to try using the L & R channels as differential inputs, as I only need one channel for my project, its a digital crossover for an active speaker. Therefore each speaker...
  25. A

    Anti Alias filters on SGTL5000

    Hi All, Well this little codec is stubborn. I just would like to run a few questions by you all, see if you have any experience beyond my experiments. Having looked at the specs of the SGTL5000, when running on VDDA of 3.3V we should expect 90dB dynamic range from the ADC. Now this is already...
  26. A

    Anti Alias filters on SGTL5000

    Thanks guys, I would have been surprised if it was not there. But very glad you have proved it. As to the question of quality. I will approach this from the supply lines first now I know the AAF is in place. I did this with the audio shield for the LPC1768, (TLV320) and managed to squeeze a good...
  27. A

    Anti Alias filters on SGTL5000

    Does anyone know if the SGTL5000 has anti-alias filters in the analogue gain stage before its ADC. The reason I ask is simple enough. I am fighting to get noise levels to an acceptable level. I have already followed a few hints such as disabling the ADC HPF, this did help. However I still have...
  28. A

    Audio Adapter SGTL5000 Group Delay

    Thanks, Hmm, I don't think this helps. They are talking about latency of over 6mS, this is an order of magnitude off the mark. It would make it totally useless in my application. But it's not real anyway. and I don't believe for a moment that this is related to the performance of the CODEC. So...
  29. A

    Audio Adapter SGTL5000 Group Delay

    Thanks, what the library supports and what the chip can do are not the same, but thanks for the heads up.
  30. A

    Audio Adapter SGTL5000 Group Delay

    Hi, I'm very interested to use the audio adapter (SGTL5000) in a servo control project. Having read the datasheet from cover to cover, I am still having to make a very important assumption about the CODEC's performance. I would be grateful if you could share any experience you have with it. I...
Back
Top