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Thread: Memory for audio card

  1. #1
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    Memory for audio card

    Hi,
    I just got a Teensy 4 and the audio card and i'm having a great time with them. I'd like to add some memory to the sound card but what is the difference between the flash chips and the ram chip available.

  2. #2
    Senior Member+ Frank B's Avatar
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  3. #3
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    Quote Originally Posted by Frank B View Post
    So if i have it right it's flash if i want storage but ram if i want to process the data in real time. I want to use it for audio processing like reverb and echo.
    Do i have it right?

  4. #4
    Senior Member PaulStoffregen's Avatar
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    There is basically no point to add the RAM chip if you're using Teensy 4.0. The only supported chip adds 128K of RAM. Teensy 4.0 has 1024K internally. Best to just use Teensy's RAM, which is much faster and more efficient than SPI for the external chip.

    But if you do add the RAM chip, the only supported effect is delay. You could use delay to build echos. So maybe that could be useful, but I would suggest you first experiment using Teensy's RAM.

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    I'll be experimenting away then with your wonderful blend of hardware and software, thank you for all of it, you rock!
    Is it wort to install the flash ram?

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    Senior Member+ MichaelMeissner's Avatar
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    Cool

    Quote Originally Posted by unawoo View Post
    I'll be experimenting away then with your wonderful blend of hardware and software, thank you for all of it, you rock!
    Is it wort to install the flash ram?
    It depends on your needs. According to some simple tests that I did, the flash memory is around 4.4 times the speed of a reasonably fast SD card (Samsung EVO select, 32GB). Note, I only tested reading, I didn't test writing. So if using a fast SD card is still too slow, soldering in the flash memory might help.

    However there are some downsides:
    • With a micro-SD card, you can take the card off of the Teensy and read/write it on your computer. With a flash memory soldered onto the audio shield, you have to download a program that dumps or reads the information via USB or to the micro-SD card. Note, that the most convenient way (teensytransfer) to get information off of that flash memory chip does NOT work on a Teensy 4.0. So I have my audio shield with stacking pins, and I move it from my Teensy 4.0 to a Teensy 3.2, 3.5, or 3.6 to run Teensy Transfer, and then I move it back.
    • The largest flash memory that I've seen at Digikey that uses the SOIC-8 form factor is the 128 megabit/16 megabyte chip (W25Q128JVSIQ-ND). You can go up to 32 gigabytes with a micro SD card. So if you need the space, the micro SD card is the way to go.
    • Surface mount soldering SOIC-8 is a little beyond the beginning through hole soldering. It isn't as bad as some of the other surface mount soldering chips, because it is relatively larger.
    • If you are interested in using the memory to play a song, note that the only current music player for flash memory uses the RAW file format. You would have to convert your WAV/MP3 files to RAW. If you wanted stereo, you would need to record two separate files, as RAW is mono.


    Here is the W25Q128JVSIQ-ND card that I bought from digi-key and soldered onto both a revision B and a revision D audio adapter:

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