max7219

A platform agnostic driver to interface with the MAX7219 (LED display driver)

What works

• Powering on/off the MAX chip
• Basic commands for setting LEDs on/off.
• Chaining support (max 8 devices)

Example

Here is a simple example for using the MAX7219 on a hifive1-revb device with e310x_hal:

#![no_std]
#![no_main]

extern crate panic_halt;

use riscv_rt::entry;
use hifive1::hal::prelude::*;
use hifive1::hal::e310x::Peripherals;
use max7219::*;

#[entry]
fn main() -> ! {
    let p = Peripherals::take().unwrap();

    // Configure clocks
    hifive1::clock::configure(p.PRCI, p.AONCLK, 320.mhz().into());

    // Configure SPI pins
    let mut gpio = p.GPIO0.split();

    let data = gpio.pin3.into_output(&mut gpio.output_en, &mut gpio.drive,
                                     &mut gpio.out_xor, &mut gpio.iof_en);
    let sck = gpio.pin5.into_output(&mut gpio.output_en, &mut gpio.drive,
                                    &mut gpio.out_xor, &mut gpio.iof_en);
    let cs = gpio.pin2.into_output(&mut gpio.output_en, &mut gpio.drive,
                                   &mut gpio.out_xor, &mut gpio.iof_en);

    let mut display = MAX7219::new(1, data, cs, sck).unwrap();

    // make sure to wake the display up
    display.power_on().unwrap();
    // write given octet of ASCII characters with dots specified by 3rd param bits
    display.write_str(0, b"pls help", 0b00100000).unwrap();
    // set display intensity lower
    display.set_intensity(0, 0x1).unwrap();

    loop {}
}

Credits

Original work by Maikel Wever. Adapted to latest embedded-hal and documented by Ales Katona.

License

Licensed under MIT license (LICENSE or http://opensource.org/licenses/MIT)