# \[Electron\] controlling 3.3v pin

**URL:** <https://community.particle.io/t/electron-controlling-3-3v-pin/32058>\
**Category:** General\
**Created:** [April 24, 2017, 10:04am UTC](https://community.particle.io/t/electron-controlling-3-3v-pin/32058 "2017-04-24T10:04:14Z")\
**Posts on this page:** 13\
**Page:** 1

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**Author:** ![nosferatu](https://avatars.discourse-cdn.com/v4/letter/n/f4b2a3/32.png) [@nosferatu](https://community.particle.io/u/nosferatu)\
**Post date:** [April 24, 2017, 10:04am UTC](https://community.particle.io/t/electron-controlling-3-3v-pin/32058/1 "2017-04-24T10:04:14Z")

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I wish to power cycle a device which is connected to the 3.3 V pin and drawing power from it. Can I control the power management IC from the software and achieve this?

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**Author:** ![kennethlimcp](https://avatars.discourse-cdn.com/v4/letter/k/c0e974/32.png) [@kennethlimcp](https://community.particle.io/u/kennethlimcp)\
**Post date:** [April 24, 2017, 10:10am UTC](https://community.particle.io/t/electron-controlling-3-3v-pin/32058/2 "2017-04-24T10:10:37Z")

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Sounds like that would work?

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**Author:** ![nosferatu](https://avatars.discourse-cdn.com/v4/letter/n/f4b2a3/32.png) [@nosferatu](https://community.particle.io/u/nosferatu)\
**Post date:** [April 24, 2017, 10:31am UTC](https://community.particle.io/t/electron-controlling-3-3v-pin/32058/3 "2017-04-24T10:31:00Z")

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Sorry, I could not follow what you said. Could you elaborate what “would work”?

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<div class="post-metadata">

**Author:** ![kennethlimcp](https://avatars.discourse-cdn.com/v4/letter/k/c0e974/32.png) [@kennethlimcp](https://community.particle.io/u/kennethlimcp)\
**Post date:** [April 24, 2017, 10:32am UTC](https://community.particle.io/t/electron-controlling-3-3v-pin/32058/4 "2017-04-24T10:32:41Z")

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With so little information in your post, that’s probably the best i can answer.

If the power management IC has control (GPIO, I2C, SPI etc) that would allow you to “reset” or on/off the power source, there’s no reason why the electron is unable to do so since those peripherals are available.

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**Author:** ![nosferatu](https://avatars.discourse-cdn.com/v4/letter/n/f4b2a3/32.png) [@nosferatu](https://community.particle.io/u/nosferatu)\
**Post date:** [April 24, 2017, 11:04am UTC](https://community.particle.io/t/electron-controlling-3-3v-pin/32058/5 "2017-04-24T11:04:08Z")

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Sorry if I was not elaborate enough - I have very little hardware background, so my vocabulary is small and the question may not have been clear.

So, the device which is drawing power from the 3V3 pin is not behaving as expected so sometimes it needs to rebooted by shutting down its power. Since it is connected through the 3V3 pin, it seems that if one could control the output on the pin - one could also control the power for the connected external device. However, I could not find the mapping, in the reference, for 3V3 pin (how do I call the pin in the code) and reset it.

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<div class="post-metadata">

**Author:** ![kennethlimcp](https://avatars.discourse-cdn.com/v4/letter/k/c0e974/32.png) [@kennethlimcp](https://community.particle.io/u/kennethlimcp)\
**Post date:** [April 24, 2017, 11:15am UTC](https://community.particle.io/t/electron-controlling-3-3v-pin/32058/6 "2017-04-24T11:15:33Z")

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What external device are you connecting to the 3V3 pin of the electron?

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<div class="post-metadata">

**Author:** ![nosferatu](https://avatars.discourse-cdn.com/v4/letter/n/f4b2a3/32.png) [@nosferatu](https://community.particle.io/u/nosferatu)\
**Post date:** [April 24, 2017, 11:22am UTC](https://community.particle.io/t/electron-controlling-3-3v-pin/32058/7 "2017-04-24T11:22:31Z")

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It is another mcu-based circuit with radio abilities. It is powered through Electron and also connected to rx/tx ports.

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<div class="post-metadata">

**Author:** ![kennethlimcp](https://avatars.discourse-cdn.com/v4/letter/k/c0e974/32.png) [@kennethlimcp](https://community.particle.io/u/kennethlimcp)\
**Post date:** [April 24, 2017, 11:23am UTC](https://community.particle.io/t/electron-controlling-3-3v-pin/32058/8 "2017-04-24T11:23:50Z")

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Is there a reset pin on that device?

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<div class="post-metadata">

**Author:** ![nosferatu](https://avatars.discourse-cdn.com/v4/letter/n/f4b2a3/32.png) [@nosferatu](https://community.particle.io/u/nosferatu)\
**Post date:** [April 24, 2017, 11:25am UTC](https://community.particle.io/t/electron-controlling-3-3v-pin/32058/9 "2017-04-24T11:25:10Z")

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No, there is none. And the complete setup is placed in a remote location. To summarily state my requirement - I am looking for way to depower the 3v3 pin and then power it up again.

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**Author:** ![nosferatu](https://avatars.discourse-cdn.com/v4/letter/n/f4b2a3/32.png) [@nosferatu](https://community.particle.io/u/nosferatu)\
**Post date:** [April 24, 2017, 11:46am UTC](https://community.particle.io/t/electron-controlling-3-3v-pin/32058/10 "2017-04-24T11:46:17Z")

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To power down 3V3 temporarily and then power it back again, can one do something like

```
int v3 = 3v3;

void setup(){
    pinMode(v3, OUTPUT);
}

void loop(){
    if (external_command_true){
        pinResetFast(v3); // power down the 3V3 pin
        delay(1000);
        pinSetFast(v3); // power it back up
    }
}
```

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<div class="post-metadata">

**Author:** ![peekay123](https://sea2.discourse-cdn.com/flex026/user_avatar/community.particle.io/peekay123/32/810_2.png) [@peekay123](https://community.particle.io/u/peekay123)\
**Post date:** [April 24, 2017, 12:00pm UTC](https://community.particle.io/t/electron-controlling-3-3v-pin/32058/11 "2017-04-24T12:00:36Z")

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@nosferatu, the Electron 3.3v output cannot be controlled as it also powers the STM32 processor of the Electron. You would need to control the power of your device through a transistor (MOSFET or other) that you control through a GPIO pin. This would require a change to your hardware however.

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<div class="post-metadata">

**Author:** ![kennethlimcp](https://avatars.discourse-cdn.com/v4/letter/k/c0e974/32.png) [@kennethlimcp](https://community.particle.io/u/kennethlimcp)\
**Post date:** [April 24, 2017, 12:00pm UTC](https://community.particle.io/t/electron-controlling-3-3v-pin/32058/12 "2017-04-24T12:00:57Z")

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Nope. That is not possible for the setup you have.

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<div class="post-metadata">

**Author:** ![nosferatu](https://avatars.discourse-cdn.com/v4/letter/n/f4b2a3/32.png) [@nosferatu](https://community.particle.io/u/nosferatu)\
**Post date:** [April 24, 2017, 12:03pm UTC](https://community.particle.io/t/electron-controlling-3-3v-pin/32058/13 "2017-04-24T12:03:51Z")

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Thanks for the clarification and the solution @peekay123