nuttx/Documentation/platforms/xtensa/esp32/boards/esp32-audio-kit/index.rst

===============
ESP32-AUDIO-KIT
===============

The `Ai-Thinker ESP32 Audio Kit <https://docs.ai-thinker.com/en/esp32-audio-kit>`_ is a development board for the ESP32 SoC from Espressif, based on Ai-Thinker ESP32-A1S audio module.

.. list-table::
   :align: center

   * - .. figure:: esp32-audio-kit.png
          :align: center

          Ai-Thinker ESP32 Audio Kit board

Features
========

  - ESP32-A1S module
  - Audio Earphones Output
  - Audio LINEIN Input
  - 2 Microphones in the board (stereo audio input)
  - 8 Buttons in the boards (1 RST Button and 7 user buttons)
  - MicroSD card slot

Some of the ESP32 I/O pins are broken out to the board's pin header.

Serial Console
==============

UART0 is, by default, the serial console. It connects to the on-board
Silabs CP2102 converter and is available on the USB connector (UART label).

It will show up as /dev/ttyUSB[n] where [n] normally is 0 if you don't have
another USB/Serial adapter connected in your computer.

Buttons and LEDs
================

Board Buttons
-------------

There are eight buttons labeled as RST, BOOT, KEY1..KEY6.
The RST button is not available to software.

The BOOT button is connected to IO0. On reset it is used as a strapping
pin to determine whether the chip boots normally or into the serial
bootloader. After reset, however, the BOOT button can be used for software
input.

Board LEDs
----------

There are several on-board LEDs for that indicate the presence of power
and USB activity.

I/O Mapping
===========

===== ========================= ==========
I/O   Signal                    Notes
===== ========================= ==========
0     BOOT Button
2     DATA0 SDCard
4     DATA1 SDCard
5     KEY6 Button
12    DATA2 SDCard
13    KEY2 Button/DATA3 SDCard  (DIP Switch)
14    CLK SDCard
15    CMD SDCard/JTAG MTDO      (DIP Switch)
18    KEY5 Button
19    KEY3 Button/LED5
21    CTRL Audio AMP
22    LED4
23    KEY4 Button
34    SDCard Detect
36    KEY1 Button
===== ========================= ==========

Configurations
==============

All of the configurations presented below can be tested by running the following commands::

    $ ./tools/configure.sh esp32-audio-kit:<config_name>
    $ make flash ESPTOOL_PORT=/dev/ttyUSB0 -j

Where <config_name> is the name of board configuration you want to use, i.e.: nsh, buttons, wifi...
Then use a serial console terminal like ``minicom`` or ``picocom`` configured to 115200 8N1.

audio
-----

This configuration uses the I2S0 peripheral and the ES8388 audio codec
present on the ESP32-Audio-Kit board to play an audio file streamed over
HTTP while connected to a Wi-Fi network.

**Simple HTTP server**

Prepare a PCM-encoded (`.wav`) audio file with 16 bits/sample (sampled at
44.1kHz). This file must be placed into a folder in a computer that could
be accessed on the same Wi-Fi network the ESP32 will be connecting to.

Python provides a simple HTTP server. `cd` to the audio file folder on the
PC and run::

  $ python3 -m http.server

  Serving HTTP on 0.0.0.0 port 8000 (http://0.0.0.0:8000/)

Look for your PC IP address and test playing the prepared audio on your
browser:

.. figure:: esp32-audio-config-file.png
          :align: center

After successfully built and flashed, connect the board to the Wi-Fi network::

  $ nsh> wapi psk wlan0 mypasswd 3
  $ nsh> wapi essid wlan0 myssid 1
  $ nsh> renew wlan0

Once connected, open NuttX's player and play the file according to its file
name and the IP address of the HTTP server (For example `tone.wav` and
`192.168.1.239:8000`, respectively)::

  $ nsh> nxplayer
  $ nxplayer> play http://192.168.1.239:8000/tone.wav

.. note::
    The codec implementation on the LyraT board was validated using 16-bit,
    44.1kHz WAV files. Other configurations might not work as expected.

nsh
---

Basic NuttShell configuration (console enabled in UART0, exposed via
USB connection by means of FT2232HL converter, at 115200 bps).

wifi
----

Enables Wi-Fi support. You can define your credentials this way::

    $ make menuconfig
    -> Application Configuration
        -> Network Utilities
            -> Network initialization (NETUTILS_NETINIT [=y])
                -> WAPI Configuration

Or if you don't want to keep it saved in the firmware you can do it
at runtime::

    nsh> wapi psk wlan0 mypasswd 3
    nsh> wapi essid wlan0 myssid 1
    nsh> renew wlan0

.. tip:: Please refer to :ref:`ESP32 Wi-Fi Station Mode <esp32_wi-fi_sta>`
  for more information.