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Thread: Audio board power consumption, etc.

  1. #1
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    Audio board power consumption, etc.

    Hi,

    I've used Teensy 2's & 3's with a number of LED projects, but now I'm investigating using one for a 4-channel 44.1 kHz data logger.

    It seems the capability of 4 channel input is now available, so I presume that requires 2 audio boards.

    Also I would like to record several days of data, so two 32GB SD cards will probably not be enough. Ideas? Is there enough bandwidth?

    And, as this system will be running on batteries, I need to estimate total power consumption so I can size the battery.

    Help greatly appreciated...

    Loren Carpenter

  2. #2
    Senior Member PaulStoffregen's Avatar
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    I just measured the current for Teensy 3.1 with two audio shields running the PassThroughQuad example. 67 mA. No SD card was present.

    Even though both boards have SD slots, you can only use 1 SD card. The signals are all in parallel, so putting a 2nd card in will cause things to not work at all.

    So far, I've never tried using a card larger than 32 GB. I know the Arduino SD library does not support exFAT. There's a chance it might be able to work if you reformatted the card with FAT32. Microsoft's format won't allow that, but 3rd party ones like "mkdosfs" in Linux will. One thing to be aware of if you try using more than 32 GB with FAT32 is apparently some versions of Microsoft chkdisk have a bug if they try to check a FAT32 volume larger than 32 GB. That's probably the reason Microsoft doesn't allow any of their software for create FAT32 larger than 32 GB.

  3. #3
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    [QUOTE=PaulStoffregen;93845]I just measured the current for Teensy 3.1 with two audio shields running the PassThroughQuad example. 67 mA. No SD card was present.

    Even though both boards have SD slots, you can only use 1 SD card. The signals are all in parallel, so putting a 2nd card in will cause things to not work at all.

    So far, I've never tried using a card larger than 32 GB. I know the Arduino SD library does not support exFAT. There's a chance it might be able to work if you reformatted the card with FAT32. Microsoft's format won't allow that, but 3rd party ones like "mkdosfs" in Linux will. One thing to be aware of if you try using more than 32 GB with FAT32 is apparently some versions of Microsoft chkdisk have a bug if they try to check a FAT32 volume larger than 32 GB. That's probably the reason Microsoft doesn't allow any of their software for create FAT32 larger than 32 GB.[/Q
    -----------------------------
    Thanks very much. Just what I wanted to know.

    Btw, that 67mA is at 5V or 3.3V?

    In either case, it's terrific.

    It will be replacing a Raspberry Pi and a Wolfson audio shield, and an Arduino Uno, even.

    Will try to get more than 32GB working. Let you know how it turns out.

    Thanks again.

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    Quote Originally Posted by PaulStoffregen View Post
    One thing to be aware of if you try using more than 32 GB with FAT32 is apparently some versions of Microsoft chkdisk have a bug if they try to check a FAT32 volume larger than 32 GB. That's probably the reason Microsoft doesn't allow any of their software for create FAT32 larger than 32 GB.
    Well, I use regularly a 64GB uSD formatted in FAT32 and use it both on Teensy and on Windows 8.1 / 10.
    for this I use a program called "guiformat.exe" downloaded from http://www.ridgecrop.demon.co.uk/ind...?guiformat.htm
    Caveat: from time to time the "guiformat" does not accept the uSD card, especially after being corrupted. In this case I use the 'official' SDFormatter from SD Association https://www.sdcard.org/downloads/for.../eula_windows/ that seems to work always but formats the 64G uSD only in exFAT, but allows me then to use the guiformatter to reformat in FAT32.

  5. #5
    Senior Member PaulStoffregen's Avatar
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    Quote Originally Posted by lorencc View Post
    Btw, that 67mA is at 5V or 3.3V?
    I measured the current from a 5V power supply connected to VIN. No USB cable was connected during the test.

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    Quote Originally Posted by PaulStoffregen View Post
    I just measured the current for Teensy 3.1 with two audio shields running the PassThroughQuad example. 67 mA. No SD card was present.

    Even though both boards have SD slots, you can only use 1 SD card. The signals are all in parallel, so putting a 2nd card in will cause things to not work at all.
    @Paul,
    from the schematic I would deduce that the 4 SPI devices (2 Mem and 2 SDCards) of two audio boards could work one at a time, obviously CS not connected in parallel, but 2nd set of CS brought separately to Teensy and SW adapted?
    Is this correct or do I miss something?

  7. #7
    Senior Member PaulStoffregen's Avatar
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    Yes, if the CS traces are cut and routed to other unused digital pins, you could indeed access two SD cards and two SPI Flash chips.

    Quote Originally Posted by WMXZ View Post
    Is this correct or do I miss something?
    However, you'll have quite a lot of software work to make this happen in any meaningful way. Both the SD and SerialFlash libraries assume only a single device. This assumption lets them use static variables and simpler code.

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