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Thread: Reduce current consumption of Teensy 3.1

  1. #1

    Reduce current consumption of Teensy 3.1


    I'm using the Teensy 3.1 in a prototype. I'm collecting sensor data with a sample rate of 1000 Hz. The Teensy needs like 600 us to get and calculate on sample which lets him wait around 400 us for the next interrupt. This sample frequency needs to be as accurate as possible and the time is tracked by the micros() command.

    1. Is there a good way to let the Teensy sleep and wake up again on the interrupt (this is High active!!!)? If so what would the start up time be like? And is is possible to use the micros() command?

    2. Is there another way to reduce the current consumption? Like turning off specific peripherals? I'm using SPI and Analog inputs.

    3. In the Low Power thread with duffs library it is mentioned that the Teensy 3.1 should draw like 18.8mA running at 48MHz. My Teensy 3.1 is running at 28mA at 48MHz! Why? It says the Mini54 chip was updated in the release 1.16, I'm using 1.2, do I need to do anything in order to get this update running like burn bootloader?

  2. #2
    Senior Member onehorse's Avatar
    Join Date
    Apr 2014
    Danville, California
    My Teesny draws 20 mA at 24 MHz and 11 mA at 4 MHz. One way to reduce power consumption is to reduce the clock speed. The lower limit is 2 MHz if your processes can stand to go this low. The other way is to use Duff's Snooze library to put the Teensy to sleep and wake it up periodically to do its business. I want to try this myself for exactly the same reason, but have yet to do so so can't report on the current reduction possible.

  3. #3
    Thx onehorse,

    but I can't reduce the clock speed. As I mentioned I need around 600us for the calculation within on sample period of 1000us with 48 MHz. Reducing the speed to even 24MHz would reduce the possible sample rate. I will take a look at the Snooze library. Maybe this is a solution...

    Is there anything I can shut down which draws a lot of current? Like an UART port or anything like that.

  4. #4
    Senior Member pictographer's Avatar
    Join Date
    May 2013
    San Jose, CA
    The datasheets page of this website has cached copies of the hardware reference manuals for the Teensy 3.0 and Teensy 3.1. Most if not all of the peripherals can be turned on and off. Going into various low-power modes automatically turns various things off. Duff's library is probably the quickest way to start experimenting with this.

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