我只能控制由Max7219供电的四个8x8 led矩阵中的第一个 [英] I am only able to control the first out of four 8x8 led matrices powered by Max7219

问题描述

我有4个8x8 LED矩阵，它们是串行连接的，我使用SPI协议与通信。

并且在重写几个库(python implementation、rust implementation、c implementation)之后， 因为它不能在我的系统上工作，并且我的代码至少能工作一点，所以我只能控制四个连接的显示器中的第一个。

以下是我的代码，用于在第一个显示器上显示类似目标的图像：

矩阵对象：

#![allow(dead_code)]
use spidev::Spidev;
use std::io::prelude::*;

// Maximum number of displays connected in series supported
const MAX_DISPLAYS: u8 = 8;

// Digits per addr
const MAX_DIGITS: u8 = 8;

// Possible command register values on the addr chip.
#[derive(Clone, Copy)]
pub enum Command {
    Noop = 0x00,
    Digit0 = 0x01,
    Digit1 = 0x02,
    Digit2 = 0x03,
    Digit3 = 0x04,
    Digit4 = 0x05,
    Digit5 = 0x06,
    Digit6 = 0x07,
    Digit7 = 0x08,
    DecodeMode = 0x09,
    Intensity = 0x0A,
    ScanLimit = 0x0B,
    Power = 0x0C,
    DisplayTest = 0x0F,
}

pub struct Matrix {
    pub spi: Spidev,
    pub devices: u8,
}
impl Matrix {
    pub fn init(&mut self) -> std::io::Result<()> {
        for device in 0..self.devices {
            self.send_bytes([device, Command::ScanLimit as u8, 0x07])?; // to scan for 8 digits or in this case columns
            self.send_bytes([device, Command::DecodeMode as u8, 0x00])?; // No Decode Mode for matrix
            self.send_bytes([device, Command::DisplayTest as u8, 0x00])?; // no displaytest desired
            self.send_bytes([device, Command::Power as u8, 0x01])?; // powers on the display
        }

        Ok(())
    }
    pub fn power_off(&mut self) -> std::io::Result<()> {
        for addr in 0..self.devices {
            self.send_bytes([addr, Command::Power as u8, 0x00])?;
        }
        Ok(())
    }
    pub fn send_command(&mut self, addr: u8, command: Command, value: u8) -> std::io::Result<()> {
        self.send_bytes([addr, command as u8, value])?;
        Ok(())
    }
    pub fn draw_raw(&mut self, addr: u8, data: [u8; 8]) -> std::io::Result<()> {
        let mut digit: u8 = 1; // column
        for b in data {
            self.send_bytes([addr, digit, b])?;
            digit += 1;
        }
        Ok(())
    }
    pub fn clear_display(&mut self, addr: u8) -> std::io::Result<()> {
        for col in 1..=MAX_DIGITS {
            self.send_bytes([addr, col, 0x00])?;
        }
        Ok(())
    }

    /// range 0 to 15
    pub fn set_intensity(&mut self, addr: u8, intesity: u8) -> std::io::Result<()> {
        self.send_bytes([addr, Command::Intensity as u8, intesity])?;
        Ok(())
    }

    fn send_bytes(&mut self, bytes: [u8; 3]) -> std::io::Result<()> {
        self.spi.write(&bytes)?;
        Ok(())
    }
}

main.rs

use spidev::{Spidev, SpidevOptions, SpiModeFlags};
use std::thread::sleep;
use std::time::Duration;

mod matrix;
use matrix::*;

fn create_spi() -> std::io::Result<Spidev> {
    let mut spi = Spidev::open("/dev/spidev0.0")?;
    let options = SpidevOptions::new()
         .bits_per_word(8)
         .max_speed_hz(20_000)
         .mode(SpiModeFlags::SPI_MODE_0)
         .build();
    spi.configure(&options)?;
    Ok(spi)
}

fn main() {
    println!("running");

    let spi = create_spi().unwrap();
    let mut matrix = Matrix{
        spi,
        devices: 4,
    };

    matrix.init().unwrap();

    matrix.draw_raw(0x01,
        [
            0b11111111,
            0b10000001,
            0b10000001,
            0b10011001,
            0b10011001,
            0b10000001,
            0b10000001,
            0b11111111
        ])
        .unwrap();

    sleep(Duration::from_secs(3));
    matrix.power_off().unwrap();
}

仅查看第一个显示，一切正常，但以下是问题：

• 在第二个显示屏上，每个像素都亮起
• 正如预期的那样，第三个显示屏完全没有亮起
• 位图&q；绘制在显示屏1和4上

我认为问题在于如何通过SPI发送数据，但我不确定。

我必须做些什么才能使其正常工作？

spi

我现在放弃了使用推荐答案的想法，并从此library

复制了方法

矩阵对象现在如下所示：

use gpio_cdev::{LineHandle, Error};

// Maximum number of displays connected in series supported
const MAX_DISPLAYS: u8 = 8;

// Digits per addr
const MAX_DIGITS: u8 = 8;

// Possible command register values on the addr chip.
#[derive(Clone, Copy)]
pub enum Command {
    Noop = 0x00,
    Digit0 = 0x01,
    Digit1 = 0x02,
    Digit2 = 0x03,
    Digit3 = 0x04,
    Digit4 = 0x05,
    Digit5 = 0x06,
    Digit6 = 0x07,
    Digit7 = 0x08,
    DecodeMode = 0x09,
    Intensity = 0x0A,
    ScanLimit = 0x0B,
    Power = 0x0C,
    DisplayTest = 0x0F,
}

pub struct Matrix {
    pub cs: LineHandle,
    pub data: LineHandle,
    pub clock: LineHandle,
    pub devices: u8,
    pub buffer: [u8; MAX_DISPLAYS as usize * 2]
}
impl Matrix {
    pub fn new(
        cs: LineHandle,
        data: LineHandle,
        clock: LineHandle,
        devices: u8,
    ) -> Self {
        Matrix { cs, data, clock, devices, buffer: [0; MAX_DISPLAYS as usize * 2] }
    }

    pub fn init(&mut self) -> Result<(), Error> {
        for device in 0..self.devices {
            self.write_raw(device, Command::ScanLimit as u8, 0x07)?; // to scan for 8 digits or in this case columns
            self.write_raw(device, Command::DecodeMode as u8, 0x00)?; // No Decode Mode for matrix
            self.write_raw(device, Command::DisplayTest as u8, 0x00)?;
            self.write_raw(device, Command::Power as u8, 0x01)?; // powers on display
        }

        Ok(())
    }
    pub fn power_off(&mut self) -> Result<(), Error>  {
        for addr in 0..self.devices {
            self.write_raw(addr, Command::Power as u8, 0x00)?;
        }
        Ok(())
    }
    pub fn send_command(&mut self, addr: u8, command: Command, value: u8) -> Result<(), Error> {
        self.write_raw(addr, command as u8, value)?;
        Ok(())
    }
    pub fn draw_raw(&mut self, addr: u8, data: [u8; 8]) -> Result<(), Error> {
        let mut digit: u8 = 1; // column
        for b in data {
            self.write_raw(addr, digit, b)?;
            digit += 1;
        }
        Ok(())
    }

    pub fn clear_display(&mut self, addr: u8) -> Result<(), Error> {
        for col in 1..=MAX_DIGITS {
            self.write_raw(addr, col, 0x00)?;
        }
        Ok(())
    }

    /// range 0 to 15
    pub fn set_intensity(&mut self, addr: u8, intesity: u8) -> Result<(), Error> {
        self.write_raw(addr, Command::Intensity as u8, intesity)?;
        Ok(())
    }

    // new method that replaces SPI
    fn write_raw(&mut self, addr: u8, header: u8, data: u8) -> Result<(), Error> {
        let offset = addr as usize * 2;
        let max_bytes = self.devices * 2;
        self.buffer = [0; MAX_DISPLAYS as usize * 2];

        self.buffer[offset] = header;
        self.buffer[offset + 1] = data;

        self.cs.set_value(0)?;
        for b in 0..max_bytes as usize {
            let value = self.buffer[b];

            for i in 0..8 {
                if value & (1 << (7 - i)) > 0 {
                    self.data.set_value(1)?;
                } else {
                    self.data.set_value(0)?;
                }

                self.clock.set_value(1)?;
                self.clock.set_value(0)?;
            }
        }
        self.cs.set_value(1)?;

        Ok(())
    }
}

我使用gpio-cdev访问GPIO引脚，如下所示：

use gpio_cdev::{Chip, LineRequestFlags, LineHandle, Error};

fn get_pins(cs: u32, data: u32, clock: u32) -> Result<(LineHandle, LineHandle, LineHandle), Error> {
    let mut chip = Chip::new("/dev/gpiochip0")?;
    
    let cs = chip
        .get_line(cs)? // 24 8
        .request(LineRequestFlags::OUTPUT, 0, "chip-select")?;

    let data = chip
        .get_line(data)? // 19 10
        .request(LineRequestFlags::OUTPUT, 0, "mosi")?;

    let clock = chip
        .get_line(clock)? // 23 11
        .request(LineRequestFlags::OUTPUT, 0, "clock")?;

    Ok( (cs, data, clock) )
}

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