main-board

Jackal main-board

Part of the Jackal project, this project implements a Teensy 4.0-based controller board that controls the Jackal system and acts as I2C Controller for the other modules.

Hardware

• MCU: Teensy 4.0
• Display: 3.2" ILI9341 IPS LCD
• Audio: Teensy audio board

Pinout

Teensy 4.0 Pin	Audio Board	LCD	Bluetooth Module	I2C Controller	Other Connections	Description
G		GND				Ground
0		CS				Chip Select
1		MISO				Using SPI port 1
2					Backlight LED	PWM Output
3			I2S LRCK			Left/Right Clock
4			I2S BCK			Bit Clock
5			DATA			Data Line
6	CS					Chip Select (memory)
7	DIN					Audio Input
8	DOUT					Audio Output
9		D/C				Data/Command
10	SDCS					Chip Select (SD card)
11	MOSI					Using SPI port 0
12	MISO					Using SPI port 0
13	SCK					Using SPI port 0
14					VU Meter	PWM Output
15	Vol pot.					Volume Potentiometer
16				SCL		Clock Line, with 4.7k pull-up to 3v3
17				SDA		Data Line, with 4.7k pull-up to 3v3
18	SDA					Audio Control Data
19	SCL					Audio Control Clock
20	LRCLK					Audio Left/Right Clock
21	BCLK					Audio Bit Clock
22						Unused
23	MCLK					Audio Master Clock
3V		RST				Reset
G	GND	GND				Ground
5V		VCC				5V Power
24						Unused
25						Unused
26		MOSI				Using SPI port 1
27		SCK				Using SPI port 1
28 - 39						Unused

The Micro USB port is used for powering the Teensy 4.0 from a battery (or computer when programming / debugging).

Notes

• For the pinout of the other microcontrollers in the project, see io-board README, and bluetooth-sink README
• All I2C lines (SDA/SCL) require 4.7k Ω pull-up resistors to 3.3V
• The Bluetooth module uses a separate I2S interface as well as I2C as target
• LCD uses a separate SPI bus due to SD noise issues

Architecture

Core Components

Audio System (AudioSystem)

Manages the audio processing pipeline using the Teensy Audio Library. Handles:

• Audio mixing
• FFT analysis
• Volume control
• EQ bands
• Audio routing between different inputs/outputs

Display (Display)

Controls the 3.2" ILI9341 IPS LCD to show:

• Current mode
• Metadata (song info, radio station, etc)
• Time
• Status information
• FFT visualization is handled separately (in FFT)

I2C Communication (I2C)

Handles communication with:

• IO expansion board (buttons, encoders)
• Bluetooth module (metadata, controls)
• FM radio module
• Other I2C peripherals

Audio Modes

The system implements different audio modes through a set of controller classes that inherit from AudioModeController, each with its own color scheme for the display:

1. Bluetooth Mode (AudioModeControllerBluetooth)

   • Streams audio from Bluetooth devices
   • Displays device name and track metadata
   • Supports EQ adjustment

2. FM Radio Mode (AudioModeControllerRadio)

   • Controls the RDA5807 FM tuner
   • Displays frequency and RDS information
   • Supports station seeking and favoriting

3. SD Playback Mode (AudioModeControllerSDPlayer)

   • Plays WAV files from SD card
   • Shows file metadata (recording time and date)
   • Supports file navigation and deletion

4. SD Recording Mode (AudioModeControllerSDRecorder)

   • Records audio to WAV files
   • Shows recording levels
   • Manages file creation/naming

5. NFC Playlist Mode (AudioModeControllerNFCPlayer)

   • Triggers playlists based on NFC tags
   • Manages playlist browsing
   • Shows track info

6. Time Setup Mode (AudioModeControllerTimeSetup)

   • Not really an audio mode :)
   • Sets the time of the Teensy 4.0 RTC
   • Will block other modes until setup is complete

7. Pong Mode (AudioModeControllerPong)

   • Not really an audio mode :)
   • A simple pong clone using the Volume and Tone sliders to control the paddles

Development

This project uses PlatformIO for development. Key files:

• platformio.ini: Project configuration
• src/main.cpp: Main program logic
• include/: Header files
• lib/: Custom libraries and dependencies

Building and Flashing

1. Install PlatformIO
2. Clone this repository
3. Open in PlatformIO IDE
4. Build and upload to Teensy 4.0

Dependencies

This project could not be built without the contributions of many talented people. The main-board has the following dependencies.

PlatformIO loads the following in libdeps:

• alex6679's teensy-4-async-inputs
• KurtE's MTP_Teensy
• KurtE's ILI9341_t3n
• Paul Stoffregen's Wire
• Paul Stoffregen's SPI
• Paul Stoffregen's Time

The platformio.ini runs a script to remove some example directories from the libdeps folder that otherwise break the build.

Additionally, a couple of libraries are copied directly in the lib:

• Ricardo Lima Caratti's RDA5807
• Some classes from JayShoe's esp32_T4_bt_music_receiver

The UI uses the Neuropolitical font converted with the ILI9341 Font Editor by Wojciech Sura.

Notes

For some reason the project stopped compiling today (01/03/2025) with .platformio\packages\framework-arduinoteensy\libraries\USBHost_t36\bluetooth.cpp:35:10: fatal error: EEPROM.h: No such file or directory.

To fix I had to go and edit the file to explicitly point at the eeprom library, replacing #include <EEPROM.h> with #include "../EEPROM/EEPROM.h".