模拟多路复用器

一个针对Rust嵌入式-hal的4051和4067系列模拟多路复用器的不依赖于平台的驱动程序

此crate提供了一个接口Multiplexer，它使得在任何74HC4051或74HC4067系列模拟多路复用器上选择通道变得非常简单。内部它会跟踪每个多路复用器的状态，允许你检查当前哪个通道是激活的，或者根据需要启用/禁用多路复用器。

支持的硬件（模拟多路复用器）

• 4067系列：74HC4067
• 4051系列：74HC4051
• ...以及任何其他使用三个或四个通道选择引脚的类似IC

用法

以下是一个使用Blue Pill（stm32f104）板的74HC4067的虚构示例...

// NOTE: This is pseudocode. It's just meant to get the concept across :)
use analog_multiplexer::Multiplexer; // Important part

use stm32f1xx_hal::gpio::State;
// The pins we're using:
use stm32f1xx_hal::gpio::gpiob::{PB0, PB5, PB12, PB13, PB14, PB15};
use stm32f1xx_hal::{adc}; // So we can read an analog pin (PB0)

fn main() {
    // stm32f1xx_hal boilerplate...
    let device = pac::Peripherals::take().unwrap();
    let mut flash = device.FLASH.constrain();
    let mut rcc = device.RCC.constrain();
    let mut _afio = device.AFIO.constrain(&mut rcc.apb2);
    let _clocks = rcc
        .cfgr
        .use_hse(8.mhz())
        .sysclk(72.mhz())
        .pclk1(36.mhz())
        .freeze(&mut flash.acr);
    // Setup ADC (we're using ADC1 for this example since we're reading PB0)
    let adc1 = adc::Adc::adc1(device.ADC1, &mut rcc.apb2, _clocks);
    // Setup GPIOB (so we can access the ADC via PB0)
    let mut gpiob = device.GPIOB.split(&mut rcc.apb2);
    // Configure PB0 as an analog input (all channels lead to this analog input pin!)
    let analog_pin = gpiob.pb0.into_analog(&mut gpiob.crl);
    // Setup PB12-PB15 for accessing S0-S3 on the 74HC4067 multiplexer
    let s0 = gpiob
        .pb12
        .into_push_pull_output_with_state(&mut gpiob.crh, State::Low);
    let s1 = gpiob
        .pb13
        .into_push_pull_output_with_state(&mut gpiob.crh, State::Low);
    let s2 = gpiob
        .pb14
        .into_push_pull_output_with_state(&mut gpiob.crh, State::Low);
    let s3 = gpiob
        .pb15
        .into_push_pull_output_with_state(&mut gpiob.crh, State::Low);
    // NOTE: On some multiplexers the S0-S3 pins are labeled A, B, C, D
    // Enable pin...  If you want to be able to enable/disable the multiplexer on-the-fly
    let en = gpiob
        .pb5
        .into_push_pull_output_with_state(&mut gpiob.crl, State::Low);
    // TIP: Just run a wire from EN to GND to keep it enabled all the time
    // Multiplexer pins are given as a tuple in the order S0-S3 then enable pin (EN):
    let pins = (s0,s1,s2,s3,en); // For 16-channel
    // let pins = (s0,s1,s2,en); // For 8-channel
    let mut multiplexer = Multiplexer::new(pins); // The important part!
    multiplexer.enable(); // Make sure it's enabled (if using EN pin)
    loop {
        for chan in 0..multiplexer.num_channels {
            multiplexer.set_channel(chan); // Change the channel
            let data: u16 = adc1.read(&mut *analog_pin).unwrap();
            // Do something with the data here
        }
    }
}

工作示例

在examples目录中有一个正确的工作示例（read_all），它使用RTIC和probe-rs，效果很好。它需要一个ST-LINK编程器，一个Blue Pill板和probe-run。

以下是我用它来读取通道15上的霍尔效应传感器的示例

许可证

许可协议

• Apache License，版本2.0（LICENSE-APACHE或https://apache.ac.cn/licenses/LICENSE-2.0）