> For the complete documentation index, see [llms.txt](https://lcav.gitbook.io/dsp-labs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://lcav.gitbook.io/dsp-labs/passthrough.md).

# 2. AUDIO PASSTHROUGH

A "passthrough" can be viewed as the audio equivalent of "hello world". In this chapter, we will build a passthrough with the hardware and software components previously introduced. Moreover, we will point out some key specifications from the microphone and the DAC (Digital-to-Analog Converter) components so that our STM32 board can successfully interface with them. This will be done in [Section 2.1](/dsp-labs/passthrough/audio-io.md).

Using the CubeMX software, we will update the configuration of the microcontroller in [Section 2.2](/dsp-labs/passthrough/updating_stm32_peripherals.md). We will guide you through the wiring in [Section 2.3](/dsp-labs/passthrough/wiring.md). Finally, we will program our passthrough in [Section 2.4](/dsp-labs/passthrough/coding.md) using the SW4STM32 software.

Highlighted boxes, as shown below, specify a task for ***you*** to determine the appropriate solution and implementation.

{% hint style="info" %}
TASK: This is a task for you!
{% endhint %}

A passthrough is a great *sanity check* when first beginning with an audio DSP system. Moreover, it serves as a useful starting point for new projects as we will see in the following chapters when we develop more complicated programs!

![](/files/-LRgWYmuzA21Blw6Nzws)

*Figure: Final wiring.*