Struct Led4 

pub struct Led4<'a>(/* private fields */);

Available on target_os=none only.

A device abstraction for a 4-digit, 7-segment LED display with blinking support.

Hardware Requirements

This abstraction is designed for common-cathode 7-segment displays where:

• Cell pins control which digit is active (LOW = on, HIGH = off)
• Segment pins control which segments light up (HIGH = on, LOW = off)

Example

use device_envoy::{Error, led4::{BlinkState, Led4, Led4Static, OutputArray}};

async fn example(p: embassy_rp::Peripherals, spawner: embassy_executor::Spawner) -> Result<(), Error> {
    // Set up cell pins (control which digit is active)
    let cells = OutputArray::new([
        embassy_rp::gpio::Output::new(p.PIN_1, embassy_rp::gpio::Level::High),
        embassy_rp::gpio::Output::new(p.PIN_2, embassy_rp::gpio::Level::High),
        embassy_rp::gpio::Output::new(p.PIN_3, embassy_rp::gpio::Level::High),
        embassy_rp::gpio::Output::new(p.PIN_4, embassy_rp::gpio::Level::High),
    ]);

    // Set up segment pins (control which segments light up)
    let segments = OutputArray::new([
        embassy_rp::gpio::Output::new(p.PIN_5, embassy_rp::gpio::Level::Low),  // Segment A
        embassy_rp::gpio::Output::new(p.PIN_6, embassy_rp::gpio::Level::Low),  // Segment B
        embassy_rp::gpio::Output::new(p.PIN_7, embassy_rp::gpio::Level::Low),  // Segment C
        embassy_rp::gpio::Output::new(p.PIN_8, embassy_rp::gpio::Level::Low),  // Segment D
        embassy_rp::gpio::Output::new(p.PIN_9, embassy_rp::gpio::Level::Low),  // Segment E
        embassy_rp::gpio::Output::new(p.PIN_10, embassy_rp::gpio::Level::Low), // Segment F
        embassy_rp::gpio::Output::new(p.PIN_11, embassy_rp::gpio::Level::Low), // Segment G
        embassy_rp::gpio::Output::new(p.PIN_12, embassy_rp::gpio::Level::Low), // Decimal point
    ]);

    // Create the display
    static LED4_STATIC: Led4Static = Led4::new_static();
    let display = Led4::new(&LED4_STATIC, cells, segments, spawner)?;

    // Display "1234" (solid)
    display.write_text(['1', '2', '3', '4'], BlinkState::Solid);
     
    // Display "rUSt" blinking
    display.write_text(['r', 'U', 'S', 't'], BlinkState::BlinkingAndOn);
     
    Ok(())
}

Beyond simple text, the driver can loop animations via Led4::animate_text. The struct owns the background task and signal wiring; create it once with Led4::new and use the returned handle for all display updates.

Implementations

impl Led4<'_>

pub fn new( led4_static: &'static Led4Static, cell_pins: OutputArray<'static, CELL_COUNT>, segment_pins: OutputArray<'static, SEGMENT_COUNT>, spawner: Spawner, ) -> Result<Self>

Creates the display device and spawns its background task; see Led4 docs.

pub const fn new_static() -> Led4Static

Creates static channel resources for Led4::new; see Led4 docs.

pub fn write_text(&self, text: [char; 4], blink_state: BlinkState)

Sends text to the display with optional blinking.

See the main Led4 example for end-to-end usage.

pub fn animate_text<I>(&self, animation: I)

where I: IntoIterator, I::Item: Borrow<AnimationFrame>,

Plays a looped text animation using the provided frames.

Example

use device_envoy::{Result, led4::{AnimationFrame, Led4, Led4Static, OutputArray}};
use embassy_time::Duration;
async fn demo(p: embassy_rp::Peripherals, spawner: Spawner) -> Result<()> {
    let cells = OutputArray::new([
        Output::new(p.PIN_1, Level::High),
        Output::new(p.PIN_2, Level::High),
        Output::new(p.PIN_3, Level::High),
        Output::new(p.PIN_4, Level::High),
    ]);
    let segments = OutputArray::new([
        Output::new(p.PIN_5, Level::Low),
        Output::new(p.PIN_6, Level::Low),
        Output::new(p.PIN_7, Level::Low),
        Output::new(p.PIN_8, Level::Low),
        Output::new(p.PIN_9, Level::Low),
        Output::new(p.PIN_10, Level::Low),
        Output::new(p.PIN_11, Level::Low),
        Output::new(p.PIN_12, Level::Low),
    ]);
    static LED4_STATIC: Led4Static = Led4::new_static();
    let display = Led4::new(&LED4_STATIC, cells, segments, spawner)?;
    const FRAME_DURATION: Duration = Duration::from_millis(120);
    let animation = [
        AnimationFrame::new(['-', '-', '-', '-'], FRAME_DURATION),
        AnimationFrame::new([' ', ' ', ' ', ' '], FRAME_DURATION),
        AnimationFrame::new(['1', '2', '3', '4'], FRAME_DURATION),
    ];
    display.animate_text(animation);
    Ok(())
}

See the example below for how to build animations.