Rust IS31FL3728 audio modulated matrix led driver

IS31FL3728 is a general purpose 8×8 LED matrix driver which features an audio frequency equalizer (EQ) mode or a general LED dot matrix display mode. The matrix picture brightness can be modulated by audio. In either the audio EQ mode or matrix display mode, the array is internally scanned, and requires only one-time programming, thus eliminating the need for real time system resource utilization.

Usage

Add the following to your Cargo.tml to get is a dependency (check that version is the latest!).

[dependency]
is31fl3728-rs="1.1.0"

Controller support

This crate provides a platform-agnostic driver for the IS31FL3728 LED Matrix. Led driver uses I2C.

Support all features of driver:

• ✅ Audio input with gain selection and audio frequency equalize
• ✅ Array mode selection (8x8 dot matrix, 7x9, 6x10, 5x11)
• ✅ Intensity of the matrix output (from 5mA to 75mA with 5mA step)
• ✅ Software shutdown and return from it.

See IS31FL3728 data sheet for details.

Crate's features

This crate based on [embedded-hal] version 1.0.

Features:

• rtt - enable debug output of communication between your app and led driver.

Important

You MUST initialize rtt in your application

• embedded-graphics - enable support of embedded-graphics. See example

Crate's specifics

The IS31FL3728 uses columns, not rows, as the more popular MAX7219 does. This is why you can't use a 8x8 led matrix editor like this one: https://xantorohara.github.io/led-matrix-editor/ . The library provides a method "draw_bitmap" which solves this trouble.

Instantiating

Create an instance of driver with the new method, by passing initialized I2C and configuration

let i2c = // depends of your MCU and HAL
let matrix_addr: u8 = 0x60;
let mut led_matrix = IS31FL3728::new(i2c, matrix_addr, MatrixDimensions::M8x8, false).unwrap();

Driver is ready to use after creating.

Main methods

• draw_column - show column on the matrix
• draw - show several columns on the matrix. Use this method for quick update matrix.
• draw_bitmap - like draw, but elements in the array are rows. So you can easy use online led matrix editors See more methods for full control.

Examples

Folder examples contains full examples:

• stm32 - tested on Nulceo-64 F401RE
• embedded-graphics - simple sprite's animation.

Quick code (STM32)

#![deny(unsafe_code)]
#![no_main]
#![no_std]


use is31fl3728_led_matrix::{LightingIntensity, MatrixDimensions, DEFAULT_LIGHTING_INTENSITY, IS31FL3728};

// Halt on panic
use panic_halt as _;

use rtt_target::rtt_init_print;

use cortex_m_rt::entry;
use stm32f4xx_hal::{self as hal, gpio::GpioExt, i2c::I2c, pac, prelude::*};

#[allow(clippy::empty_loop)]
#[entry]
fn main() -> ! {
    rtt_init_print!();

    let dp = pac::Peripherals::take().unwrap();

    let rcc = dp.RCC.constrain();
    let clocks = rcc.cfgr.use_hse(8.MHz()).sysclk(84.MHz()).freeze();
    let mut delay = dp.TIM5.delay_us(&clocks);      


    let gpiob = dp.GPIOB.split();

    let pb8_scl = gpiob.pb8;
    let pb9_sda = gpiob.pb9;

    // Initiation of I2C
    let i2c1 = I2c::new(
        dp.I2C1,
        (pb8_scl, pb9_sda),
        hal::i2c::Mode::standard(400.kHz()),
        &clocks,
    );

    let matrix_addr: u8 = 0x60;
    let mut led_matrix = IS31FL3728::new(i2c1, matrix_addr, MatrixDimensions::M8x8, false).unwrap();
    led_matrix.clear().unwrap();

    let picture = [
        0b00000000,
        0b01100110,
        0b11111111,
        0b11111111,
        0b11111111,
        0b01111110,
        0b00111100,
        0b00011000,
    ];

    led_matrix.draw_bitmap(&picture).unwrap();
    led_matrix.set_intensity(LightingIntensity::C20mA).unwrap();

    loop {
        led_matrix.software_on().unwrap();
        led_matrix.set_intensity(LightingIntensity::C10mA).unwrap();
        delay.delay_ms(150);
        led_matrix.set_intensity(LightingIntensity::C25mA).unwrap();
        delay.delay_ms(150);
        led_matrix.set_intensity(DEFAULT_LIGHTING_INTENSITY).unwrap();
        delay.delay_ms(500);

        led_matrix.set_intensity(LightingIntensity::C25mA).unwrap();
        delay.delay_ms(150);
        led_matrix.set_intensity(LightingIntensity::C10mA).unwrap();
        delay.delay_ms(150);
        led_matrix.software_shutdown().unwrap();
        delay.delay_ms(300);
    }
}

Result of application: