[Noisebridge-discuss] low power / sleep modes on Teensy?

[Daniel Pitts]

It depends on how the communication is configured.  I know on the 
Arduino that enabling serial communication with the chip actually causes 
the reset pin to be activated, restarting the whole thing (unless you 
add a capacitor to delay the signal long enough).  This is to allow 
programming using the built-in bootloader.  I don't know if its handled 
in the FTDI (newer Arduino's actually use another AVR MCU as the USB 
chip, not an FDTI).

I wouldn't be surprised if Teensy handled this similarly. I don't really 
know anything about the USB spec, but it is possible there is some sort 
of "wake-up" signal to indicate communication is about to start, which 
could trigger an interrupt on the Teensy's MCU.

It might be worth prototyping this on a breadboard.  BTW, soldering 
isn't permanent. It's just less temporary ;-)

On 3/10/13 1:44 PM, Glenn Wright wrote:
> Hi all, I have a question that I have not been able to solve on 
> Google, nor by tinkering-without-soldering-permanently, so I was 
> wondering if anyone knew the answer from experience.  How do the 
> Arduino sleep modes (and libraries such as Narcoleptic) work on a 
> Teensy, given that the controller communicates directly with the USB 
> port instead of using an FTDI chip?  Does putting the Teensy into 
> low-power modes shut off power to the USB port?  If so, is there any 
> way to subsequently reprogram the board via USB? I noticed that the 
> Narcoleptic library does *not* turn off the power to the FTDI chip on 
> a normal Arduino, but I'm not sure what the implications would be on 
> the Teensy.  On the PJRC website, there is this bit of incredibly 
> useful information regarding turning off power to the USB port on a 
> Teensy:
>
> "TODO: code samples"
>
> -- 
> -Glenn
>
>
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