> For the complete documentation index, see [llms.txt](https://dahl-design.gitbook.io/ddc/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dahl-design.gitbook.io/ddc/switch-library/utility.md).

# Utility

Here are useful functions for controller maintenance.

#### firmwareUploadMode()

{% tabs %}
{% tab title="Description" %}
This function is RP2040 specific. It will let you set up two buttons to reboot the RP2040 chip into USB storage device mode when held together for a set amount of time. This allows you to quickly update/swap firmware on your controller without having to take it apart to use the BOOTSEL button. 

This function will not produce any button presses, so you should also use functions like pushButton(), modButton(), biteButton() etc. for these two buttons.
{% endtab %}

{% tab title="Example" %}
`void firmwareUploadMode(int Arow, int Acol, int Brow, int Bcol, int timer)`

For two buttons on row 1 column 3 and row 2 column 2:

`firmwareUploadMode(1,3,2,2,4000);`

These two buttons will behave like normal buttons, but if held together for 4000 ms (4 seconds) you will reboot the controller into USB storage mode. 
{% endtab %}

{% tab title="Requirements" %}

* None
  {% endtab %}
  {% endtabs %}