# 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](https://lcav.gitbook.io/dsp-labs/passthrough/audio-io).

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

![](https://2920775871-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LPoyKvCv4LRUhdM3-rr%2F-LRgWXZcG-lrH5oKZak6%2F-LRgWYmuzA21Blw6Nzws%2Ffinal_wiring.jpg?generation=1542640257219206\&alt=media)

*Figure: Final wiring.*