ESP32 Interactive UART Terminal

An ESP32 project implementing an interactive UART command-line interface with LED blinking control and I2S audio tone generation.

Features

Blink Control

• blink on - Enable LED blinking
• blink off - Disable LED blinking
• blink freq <ms> - Set blink period in milliseconds

I2S Audio

• i2s init <channel> <sample_rate> <bit_width> <stereo/mono> - Initialize I2S peripheral
  • Example: i2s init 0 44100 16 stereo
• i2s tone <freq> - Play a tone at specified frequency (100 Hz to 15000 Hz)
• i2s start - Start I2S transmission
• i2s stop - Stop I2S transmission

General

• clock - Display system clock frequencies
• reset - Restart the ESP32
• i2c detect - Scan I2C bus for devices
• help - Display all available commands

Hardware Requirements

• ESP32 development board
• LED on GPIO2 (built-in on most ESP32 dev boards)
• I2S DAC or amplifier on:
  • BCLK: GPIO26
  • LRCLK/WS: GPIO25
  • DOUT: GPIO22

ESP-IDF Version

Developed using ESP-IDF v6.0

Build and Flash

1. Set up ESP-IDF environment:

   source ~/.espressif/v6.0/esp-idf/export.sh

2. Build the project:

   cd blinky
   idf.py build

3. Flash to ESP32 (replace PORT with your serial port):

   idf.py -p /dev/cu.SLAB_USBtoUART flash

Usage

Connect to the ESP32 via serial terminal at 115200 baud:

screen /dev/cu.SLAB_USBtoUART 115200

Type commands and press Enter. Start with help to see available commands.

Project Structure

opencode/
├── blinky/
│   ├── main/
│   │   ├── blinky.c          # Main application with UART terminal and I2S
│   │   └── CMakeLists.txt   # Component configuration
│   ├── CMakeLists.txt       # Project configuration
│   └── sdkconfig.defaults  # Default SDK configuration
└── README.md

Console Log Example

=== Blinky UART Terminal ===
Type 'help' for commands
> help

Commands:
  blink on       - Enable blinking
  blink off      - Disable blinking
  blink freq <ms>- Set blink period in ms
  i2s init <ch> <sr> <w> <s/m> - Init I2S
  i2s tone <freq>- Play tone 100-15000Hz
  i2s start      - Start I2S
  i2s stop       - Stop I2S
  i2c detect     - Scan I2C bus
  clock          - Show system clocks
  reset          - Restart ESP32
  help           - Show this help
> blink off
Blinking disabled
> blink freq 500
Blink frequency set
> blink on
Blinking enabled
> i2s init 0 44100 16 stereo
I2S initialized
> i2s tone 440
Tone playing
> i2s tone 880
Tone playing
> i2s tone 1760
Tone playing
> i2s stop
I2S stopped
> clock
System Clocks:
  CPU: 240000000 Hz
> i2c detect
I2C Scan:
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:         -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- --
> reset
Resetting ESP32...
=== Blinky UART Terminal ===
Type 'help' for commands
> invalid_command
Unknown command. Type 'help'
> help

Commands:
  blink on       - Enable blinking
  blink off      - Disable blinking
  blink freq <ms>- Set blink period in ms
  i2s init <ch> <sr> <w> <s/m> - Init I2S
  i2s tone <freq>- Play tone 100-15000Hz
  i2s start      - Start I2S
  i2s stop       - Stop I2S
  help           - Show this help
>