# GPIO pin assignment

**URL:** <https://klipper.discourse.group/t/gpio-pin-assignment/19277>\
**Category:** General Discussion\
**Created:** [October 8, 2024, 7:45pm UTC](https://klipper.discourse.group/t/gpio-pin-assignment/19277 "2024-10-08T19:45:20Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![Hypoxic01](https://avatars.discourse-cdn.com/v4/letter/h/ed655f/32.png) [@Hypoxic01](https://klipper.discourse.group/u/Hypoxic01)\
**Post date:** [October 8, 2024, 7:45pm UTC](https://klipper.discourse.group/t/gpio-pin-assignment/19277/1 "2024-10-08T19:45:21Z")

</div>

### Basic Information:

[Voron 0.2] Printer Model:  
[MP4 + CM4  
[logs-20241008-233612.zip](https://klipper.discourse.group/uploads/short-url/nQeBaDX6sZWguKQfdai7nukneNF.zip) (82.6 KB)  
] MCU / Printerboard:  
 Host / SBC  
[uploaded

 ![Screenshot 2024-10-08 233735](https://global.discourse-cdn.com/free1/uploads/klipper/original/2X/f/f729b51cdb13ebdcd46eed28070ef24ba6a7a4ac.png)  
 ![Screenshot 2024-10-08 233912](https://global.discourse-cdn.com/free1/uploads/klipper/original/2X/3/358b3d393dff6497902ab0a03ee415a7c7ccbe83.png)  
 ![Screenshot 2024-10-08 234009](https://global.discourse-cdn.com/free1/uploads/klipper/original/2X/f/fa74ccdc92c396863eedb20dadd10e921b320c8b.jpeg)  
 ![Screenshot 2024-10-08 234053](https://global.discourse-cdn.com/free1/uploads/klipper/original/2X/7/73370448987f39f9d131c57a8f67704860022c5d.png)  
] klippy.log

_Fill out above information and_ **_in all cases attach your_ `klippy.log` _file_** (use zip to compress it, if too big). _Pasting your_ `printer.cfg` _is **not** needed_  
_ **Be sure to check our “Knowledge Base” Category first. Most relevant items, e.g. error messages, are covered there** _

### Describe your issue:

Hello, I have a Voron Trident and managed to set up some additional fans via the GPIO pins..

I also have a V0.2 with a CM4 and tried to make use of the GPIO pins there for a servo to add a nozzle cleaner.  
However, I can’t get rid of the error with Pin must be specified.l  
I’ve attached I believe necessary screen shots and hope someone can see the error I’m making.

 ![Screenshot 2024-10-08 234451](https://global.discourse-cdn.com/free1/uploads/klipper/original/2X/e/e1291d383caa5efab518f8ea395d9bb4f4ba3004.png)

Thanks in advance.

---

<div class="post-metadata">

**Author:** ![EddyMI3D](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/eddymi3d/32/1981_2.png) [@EddyMI3D](https://klipper.discourse.group/u/EddyMI3D)\
**Post date:** [October 8, 2024, 8:17pm UTC](https://klipper.discourse.group/t/gpio-pin-assignment/19277/2 "2024-10-08T20:17:52Z")

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Obviously. There is nothing in that macro:

```auto
...
[exclude_object]

[servo NozzleBrush]

[mcu]
serial = /dev/serial/by-id/usb-Klipper_stm32g0b1xx_1E0017001450415833323520-if00
...

```

[https://www.klipper3d.org/Config\_Reference.html#servo](https://www.klipper3d.org/Config_Reference.html#servo)

---

<div class="post-metadata">

**Author:** ![Hypoxic01](https://avatars.discourse-cdn.com/v4/letter/h/ed655f/32.png) [@Hypoxic01](https://klipper.discourse.group/u/Hypoxic01)\
**Post date:** [October 8, 2024, 8:33pm UTC](https://klipper.discourse.group/t/gpio-pin-assignment/19277/3 "2024-10-08T20:33:10Z")

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Yep… assigned the wrong file name…DUH!!

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<div class="post-metadata">

**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/klipper/original/1X/64419bf2aac6639e6ef5cef200dcd456b0a01ac3.png) [@system](https://klipper.discourse.group/u/system)\
**Post date:** [December 7, 2024, 8:33pm UTC](https://klipper.discourse.group/t/gpio-pin-assignment/19277/4 "2024-12-07T20:33:36Z")

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