/*
Simplified Embedded Rust: ESP Core Library Edition
Programming ADCs - Temperature Sensing Application Example
*/

#![no_std]
#![no_main]

use esp_backtrace as _;
use esp_hal::{
    analog::adc::{Adc, AdcConfig, Attenuation},
    delay::Delay,
    gpio::Io,
    prelude::*,
};
use esp_println::println;
use libm::log;

#[entry]
fn main() -> ! {
    let peripherals =
        esp_hal::init(esp_hal::Config::default());
    let delay = Delay::new();

    // Instantiate and Create Handle for IO
    let io = Io::new(peripherals.GPIO, peripherals.IO_MUX);

    // Create handle for ADC configuration parameters
    let mut adc_config = AdcConfig::new();

    // Configure ADC pin
    let mut adc_pin = adc_config.enable_pin(
        io.pins.gpio4,
        Attenuation::Attenuation11dB,
    );

    // Create ADC Driver
    let mut adc = Adc::new(peripherals.ADC1, adc_config);

    const B: f64 = 3950.0; // B value of the thermistor
    const VMAX: f64 = 4095.0; // Full Range Voltage

    loop {
        // Get ADC reading
        let sample: u16 =
            adc.read_oneshot(&mut adc_pin).unwrap();
        // For blocking read
        // let sample: u16 = nb::block!(adc.read_oneshot(&mut adc_pin)).unwrap();

        // Convert to temperature
        let temperature = 1.
            / (log(1. / (VMAX / sample as f64 - 1.)) / B
                + 1.0 / 298.15)
            - 273.15;

        // Print the temperature output
        println!(
            "Temperature {:02} Celcius\r",
            temperature
        );

        // Wait some time before next measurement
        delay.delay_millis(500_u32);
    }
}