diff --git a/esp/rust/03_aht20/Cargo.toml b/esp/rust/03_aht20/Cargo.toml index caa0b28..0a030f6 100644 --- a/esp/rust/03_aht20/Cargo.toml +++ b/esp/rust/03_aht20/Cargo.toml @@ -25,6 +25,11 @@ experimental = ["esp-idf-svc/experimental"] [dependencies] log = "0.4" esp-idf-svc = "0.51" +embedded-hal = "1.0.0" +esp-backtrace = "0.17.0" +esp-hal = { version = "1.0.0-rc.0", features = ["unstable"] } +fugit = "0.3.7" +esp-println = { version = "0.15.0", features = ["log-04"] } # --- Optional Embassy Integration --- # esp-idf-svc = { version = "0.51", features = ["critical-section", "embassy-time-driver", "embassy-sync"] } diff --git a/esp/rust/03_aht20/src/main.rs b/esp/rust/03_aht20/src/main.rs index 9f40bc6..efc88c0 100644 --- a/esp/rust/03_aht20/src/main.rs +++ b/esp/rust/03_aht20/src/main.rs @@ -1,10 +1,152 @@ -fn main() { - // It is necessary to call this function once. Otherwise some patches to the runtime - // implemented by esp-idf-sys might not link properly. See https://github.com/esp-rs/esp-idf-template/issues/71 - esp_idf_svc::sys::link_patches(); +#![no_std] +#![no_main] - // Bind the log crate to the ESP Logging facilities - esp_idf_svc::log::EspLogger::initialize_default(); - - log::info!("Hello, world!"); +/// Represents a reading from the sensor. +pub struct SensorReading { + pub humidity: T, + pub temperature: T, +} + +/// Possible errors when interacting with the sensor. +#[derive(Debug)] +pub enum SensorError { + ChecksumMismatch, + Timeout, + PinError, +} + +pub struct Dht20 { + pub i2c: I, + pub delay: D, +} + +impl Dht20 { + const SENSOR_ADDRESS: u8 = 0x38; + + pub fn new(i2c: I, delay: D) -> Self { + Self { i2c, delay } + } + + pub fn read(&mut self) -> Result, SensorError> { + // Check status + let mut status_response: [u8; 1] = [0; 1]; + let _ = self + .i2c + .write_read(Self::SENSOR_ADDRESS, &[0x71], &mut status_response); + + // Calibration if needed + if status_response[0] & 0x18 != 0x18 { + let _ = self.i2c.write(Self::SENSOR_ADDRESS, &[0x1B, 0, 0]); + let _ = self.i2c.write(Self::SENSOR_ADDRESS, &[0x1C, 0, 0]); + let _ = self.i2c.write(Self::SENSOR_ADDRESS, &[0x1E, 0, 0]); + } + + // Trigger the measurement + self.delay.delay_ms(10); + let _ = self.i2c.write(Self::SENSOR_ADDRESS, &[0xAC, 0x33, 0x00]); + + // Read the measurement status + self.delay.delay_ms(80); + loop { + let mut measurement_status_response: [u8; 1] = [0; 1]; + let _ = self + .i2c + .read(Self::SENSOR_ADDRESS, &mut measurement_status_response); + let status_word = measurement_status_response[0]; + if status_word & 0b1000_0000 == 0 { + break; + } + self.delay.delay_ms(1); + } + + // Read the measurement (1 status + 5 data + 1 crc) + let mut measurement_response: [u8; 7] = [0; 7]; + let _ = self + .i2c + .read(Self::SENSOR_ADDRESS, &mut measurement_response); + + // Humidity 20 bits (8 + 8 + 4) + let mut raw_humidity = measurement_response[1] as u32; + raw_humidity = (raw_humidity << 8) + measurement_response[2] as u32; + raw_humidity = (raw_humidity << 4) + (measurement_response[3] >> 4) as u32; + let humidity_percentage = (raw_humidity as f32 / ((1 << 20) as f32)) * 100.0; + + // Temperature 20 bits + let mut raw_temperature = (measurement_response[3] & 0b1111) as u32; + raw_temperature = (raw_temperature << 8) + measurement_response[4] as u32; + raw_temperature = (raw_temperature << 8) + measurement_response[5] as u32; + let temperature_percentage = (raw_temperature as f32 / ((1 << 20) as f32)) * 200.0 - 50.0; + + // Compare the calculated CRC with the received CRC + let data = &measurement_response[..6]; + let received_crc = measurement_response[6]; + let calculated_crc = Self::calculate_crc(data); + if received_crc != calculated_crc { + return Err(SensorError::ChecksumMismatch); + } + + Ok(SensorReading { + humidity: humidity_percentage, + temperature: temperature_percentage, + }) + } + + fn calculate_crc(data: &[u8]) -> u8 { + let polynomial = 0x31u8; // x^8 + x^5 + x^4 + 1 + let mut crc = 0xFFu8; + + for &byte in data { + crc ^= byte; + // CRC8 - process every bit + for _ in 0..8 { + if crc & 0x80 != 0 { + crc = (crc << 1) ^ polynomial; + } else { + crc <<= 1; + } + } + } + + crc + } +} + +use embedded_hal::{delay::DelayNs, i2c::I2c as I2cEmbedded}; +use esp_backtrace as _; +use esp_hal::{ + clock::CpuClock, + delay::Delay, + gpio::{Level, Pull}, + i2c::master::I2c, + xtensa_lx_rt::entry, +}; +use fugit::{ExtU64, HertzU32}; + +#[entry] +fn main() -> ! { + let peripherals = esp_hal::init(esp_hal::Config::default()); + esp_println::logger::init_logger_from_env(); + let mut delay = Delay::new(); + + // TODO: Remove unwrap + let i2c_for_dht20 = + esp_hal::i2c::master::I2c::new(peripherals.I2C0, esp_hal::i2c::master::Config::default()) + .unwrap() + .with_sda(peripherals.pins.gpio21) + .with_scl(peripherals.pins.gpio22); + let mut dht20 = Dht20::new(i2c_for_dht20, delay); + + loop { + delay.delay_ms(5000); + match dht20.read() { + Ok(sensor_reading) => log::info!( + "DHT 20 Sensor - Temperature: {} °C, humidity: {} %", + sensor_reading.temperature, + sensor_reading.humidity + ), + Err(error) => log::error!("An error occurred while trying to read sensor: {:?}", error), + } + + log::info!("-----"); + } }