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Chronos buzzer does not work on battery

Kuba Raczkowski
Prodigy 130 points


Hi,

I am playing around with the chronos, rewriting everything myself to better understand the msp430, however I run into a problem with the buzzer.

I wrote a simple program that generates a PWM (~3kHz) on the buzzer's output (P2.7) and it works well, but ONLY when chronos is connected to the USB programmer OR to external battery pack (3V). When working on the cell battery, the piezo does not give any sound. (yes I did try changing the battery :D )

Is there any special handling necessary to get more power from the battery, or some drive-strength setting, etc. that I missed?

I tried setting the drive strength of the pin to high, asking the PMM module for high power, setting the PMM voltage lower or higher, but nothing gives any change...

Thanks for any suggestions!

Kuba

  • 0
    Guru 92251 points

    When running from the 3V battery, I found that the buzzer only sounded the chronos assembly was fitted to the watch and the backplate screwed on. There is a "spring" which comes out of the chronos assembly which looks like it presses against the backplate which I assumed was required to get the buzzer to sound.

    (I didn't try sounding the buzzer when supplied from the 3.6V USB programmer)

  • 0 in reply to Chester Gillon
    Prodigy 130 points

    Dear Chester,

    Thank you for your answer. I tried with the cover screwed onto the main board (and the watch case) but without success. Why should it work differently than with cables connected to the buzzer in the cover?

    I think there is something I miss in the code, but don't know what. I will make a minimal-working-example and post it here...

    Kuba

  • 0 in reply to Kuba Raczkowski
    Guru 58965 points

    Mine works well when it is used to weak up the flee sleeping under the watch.

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