<p>As you point out, the <a href="https://www.pjrc.com/store/teensy40.html#pins" rel="nofollow noreferrer">Teensy 4.0 online documentation</a> mentions that neither the digital GPIO nor analog I/O are 5v-tolerant pins. It appears that the ESCs in the kit you linked to only have a PWM signal input and no bi-directional communication bus (<em>e.g. Bidirectional DSHOT</em>), so the only voltage present on the PWM input line would be one that you create. (<em>thus there is no real danger of the ESC putting 5v on the signal line, though the 5v BEC pin will still have it</em>)</p>
<p>However, you may run into another issue when trying to issue commands to the ESC from the Teensy. Being a 3v3 logic-level device, its logic high may not be sufficient voltage to &quot;trigger&quot; the ESC, depending on how the ESC's software interprets incoming signals. You can address this with a &quot;level converter&quot; (<em>essentially just a set of small BJT transistors to switch 5v lines with 3v3 ones and vice versa</em>) like <a href="https://smile.amazon.com/SongHe-Channels-Converter-Bi-Directional-Shifter/dp/B07YZTW2SM" rel="nofollow noreferrer">this one from Amazon</a>.</p>

CC BY-SA 4.0
2021-06-10T01:37:47.880Z
thanks! actually the teensy flight controller code i am using is made to work with the Oneshot protocol and PWM for the ESCs. so hopefully that won't be a problem. i have been trying to test some bidirectional logic converters that i have but i have had no luck. if you have a good link/video that shows how to test/use them correctly, please let me know!
Ahmed Anwer
CC BY-SA 4.0
2021-06-10T02:42:38.247Z
Oh, got it! Oneshot is also a uni-directional protocol, so there shouldn't be any dissimilar issues to the PWM things I mentioned in my answer. Best of luck for the project!
ifconfig
CC BY-SA 4.0
2021-06-10T02:42:59.667Z
Could you clarify what exactly you mean by "bidirectional logic converter"?
ifconfig
CC BY-SA 4.0
2021-06-10T07:06:29.470Z
the one you sent are bidirectional logic converters, they are the ones used for I2C when micro controllers of different logic levels are trying to exchange data. i think they can be used for unidirectional purposes as well. i found a stackexchange post on electrical engineering for it actually, so i will use that! thanks tho!
Ahmed Anwer
CC BY-SA 4.0
2021-06-15T15:33:34.097Z
Nice answer! Most likely the ESC will accept 3V3 inputs anyway; they are usually STM-based, and the thresholds are hardware, not software dependent. according to [this answer](https://electronics.stackexchange.com/a/394850) 3.3v should be registered as high even if the MCU is powered from 5V.
Unless the ESC has an optocoupler on the data lines, in which case all bets are off.
FlashCactus
CC BY-SA 4.0
2021-06-15T17:10:48.973Z
Yeah, thanks for the added details, @FlashCactus! I felt like keeping my answer open-ended, especially because the ESCs the OP pointed to appeared to be older OEM designs and not like BLHeli.
ifconfig
CC BY-SA 4.0
2021-06-10T00:15:57.840Z
2021-06-10T00:15:57.840Z
ifconfig
<p>the flight controller i am using is a custom one, which is a teensy 4.0 microcontroller. it cannot have more than 3.3V into its GPIO pins. I know I can use the 5V from the BEC of the ESC to power my teensy, but will the digital control pins from the ESC apply more than 3.3V at the pins of the teensy?</p>
<p><a href="https://www.ebay.ca/itm/284005585210?hash=item42200d513a:g:4-IAAOSwENVfWIUH" rel="noreferrer">this</a> the drone motor (and frame) that i am using.</p>

<esc><flight-controller><diy>
what is the voltage output from the ESCs of drone motors?
Ahmed Anwer
# what is the voltage output from the ESCs of drone motors?

(Asked by: username_0 on 2021-06-09)

the flight controller i am using is a custom one, which is a teensy 4.0 microcontroller. it cannot have more than 3.3V into its GPIO pins. I know I can use the 5V from the BEC of the ESC to power my teensy, but will the digital control pins from the ESC apply more than 3.3V at the pins of the teensy?

[this](https://www.ebay.ca/itm/284005585210?hash=item42200d513a:g:4-IAAOSwENVfWIUH) the drone motor (and frame) that i am using.

**Tags:** esc, flight-controller, diy


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## 1 answers

### Answer by username_1 on 2021-06-10. Score: 4 | Accepted answer

As you point out, the [Teensy 4.0 online documentation](https://www.pjrc.com/store/teensy40.html#pins) mentions that neither the digital GPIO nor analog I/O are 5v-tolerant pins. It appears that the ESCs in the kit you linked to only have a PWM signal input and no bi-directional communication bus (*e.g. Bidirectional DSHOT*), so the only voltage present on the PWM input line would be one that you create. (*thus there is no real danger of the ESC putting 5v on the signal line, though the 5v BEC pin will still have it*)

However, you may run into another issue when trying to issue commands to the ESC from the Teensy. Being a 3v3 logic-level device, its logic high may not be sufficient voltage to "trigger" the ESC, depending on how the ESC's software interprets incoming signals. You can address this with a "level converter" (*essentially just a set of small BJT transistors to switch 5v lines with 3v3 ones and vice versa*) like [this one from Amazon](https://smile.amazon.com/SongHe-Channels-Converter-Bi-Directional-Shifter/dp/B07YZTW2SM).

> **Comments:**
> **username_0**: thanks! actually the teensy flight controller code i am using is made to work with the Oneshot protocol and PWM for the ESCs. so hopefully that won't be a problem. i have been trying to test some bidirectional logic converters that i have but i have had no luck. if you have a good link/video that shows how to test/use them correctly, please let me know!  
> **username_1**: Oh, got it! Oneshot is also a uni-directional protocol, so there shouldn't be any dissimilar issues to the PWM things I mentioned in my answer. Best of luck for the project!  
> **username_1**: Could you clarify what exactly you mean by "bidirectional logic converter"?  
> **username_0**: the one you sent are bidirectional logic converters, they are the ones used for I2C when micro controllers of different logic levels are trying to exchange data. i think they can be used for unidirectional purposes as well. i found a stackexchange post on electrical engineering for it actually, so i will use that! thanks tho!  
> **username_2**: Nice answer! Most likely the ESC will accept 3V3 inputs anyway; they are usually STM-based, and the thresholds are hardware, not software dependent. according to [this answer](https://electronics.stackexchange.com/a/394850) 3.3v should be registered as high even if the MCU is powered from 5V. Unless the ESC has an optocoupler on the data lines, in which case all bets are off.  
> **username_1**: Yeah, thanks for the added details, @username_2! I felt like keeping my answer open-ended, especially because the ESCs the OP pointed to appeared to be older OEM designs and not like BLHeli.  

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