Read co2 sensor data

Cargo.lock

@@ -152,6 +152,7 @@ dependencies = [
  "embedded-storage",
  "fixed",
  "fixed-macro",
+ "futures",
  "heapless 0.8.0",
  "log",
  "panic-probe",

Cargo.toml

@@ -4,6 +4,8 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+futures = { version = "0.3", default-features = false }
+
 embassy-embedded-hal = { version = "0.1.0", features = ["defmt"] }
 embassy-sync = { version = "0.6.0", features = ["defmt"] }
 embassy-executor = { version = "0.5.0", features = ["task-arena-size-32768", "arch-cortex-m", "executor-thread", "executor-interrupt", "defmt", "integrated-timers"] }

src/main.rs

@@ -6,6 +6,8 @@
 #![no_std]
 #![no_main]
 
+use core::future::ready;
+
 use byteorder::ByteOrder;
 use defmt::*;
 use embassy_embedded_hal::SetConfig;
@@ -17,7 +19,9 @@ use embassy_rp::{gpio, spi};
 use embedded_hal_bus::spi::ExclusiveDevice;
 use embedded_sdmmc::sdcard::{DummyCsPin, SdCard};
 use embedded_sdmmc::{Block, BlockDevice, BlockIdx, VolumeIdx};
+use futures::{FutureExt, TryFutureExt};
 use gpio::{Level, Output};
+use usbd_hid::descriptor::MouseReport;
 use {defmt_rtt as _, panic_probe as _};
 
 use embassy_rp::i2c::{self, Config};
@@ -31,8 +35,14 @@ struct DummyTimesource();
 
 /// I2C Address of the co2 sensor
 const CCS811_I2C_ADDRESS: u16 = 0x5A;
-/// I2C Register addresses of the co2 sensor
+/// Application I2C Register addresses of the co2 sensor
 const CCS811_REGISTER_STATUS: u8 = 0x00;
+const CCS811_REGISTER_MEAS_MODE: u8 = 0x01;
+const CCS811_REGISTER_ALG_RESULT_DATA: u8 = 0x02;
+
+/// Bootloader I2C Register addresses of the co2 sensor
+const CCS811_REGISTER_BOOTLOADER_APP_START: u8 = 0xF4;
+const CCS811_REGISTER_BOOTLOADER_STATUS: u8 = CCS811_REGISTER_STATUS;
 
 impl embedded_sdmmc::TimeSource for DummyTimesource {
     fn get_timestamp(&self) -> embedded_sdmmc::Timestamp {
@@ -69,7 +79,7 @@ async fn main(spawner: Spawner) {
     Timer::after(Duration::from_secs(1)).await;
 
     debug!("Writing to I2C");
-    let mut status = [42];
+    let mut status = [42u8];
     i2c.write_async(CCS811_I2C_ADDRESS, [CCS811_REGISTER_STATUS])
         .await
         .unwrap();
@@ -77,10 +87,71 @@ async fn main(spawner: Spawner) {
     i2c.read_async(CCS811_I2C_ADDRESS, &mut status)
         .await
         .unwrap();
+    let status = status[0];
 
     info!("Reported status: {}", status);
+    match status {
+        16u8 => {}
+        144u8 => {
+            warn!("Sensor already in APP mode! Configuration may come from previous boot.");
+        }
+        unexpected => {
+            warn!(
+                "Sensor reported unexpected state after boot: {}",
+                unexpected
+            );
+        }
+    }
 
-    debug!("TASK ENDED: Main")
+    // APP_START does not require to write data
+    i2c.write_async(CCS811_I2C_ADDRESS, [CCS811_REGISTER_BOOTLOADER_APP_START])
+        .await
+        .unwrap();
+
+    // After APP_START, we have to wait 1 ms (according to datasheet)
+    Timer::after(Duration::from_millis(1000)).await;
+
+    // Mode 1 is 1 measurement per second
+    i2c.write_async(CCS811_I2C_ADDRESS, [CCS811_REGISTER_MEAS_MODE, 16])
+        .await
+        .unwrap();
+
+    loop {
+        let mut status = [42u8];
+        i2c.write_async(CCS811_I2C_ADDRESS, [CCS811_REGISTER_STATUS])
+            .await;
+        // .unwrap();
+        i2c.read_async(CCS811_I2C_ADDRESS, &mut status).await;
+        // .unwrap();
+        let status = status[0];
+
+        let mut measured_value_buffer = [42u8; 2];
+        let address_written = i2c
+            .write_async(CCS811_I2C_ADDRESS, [CCS811_REGISTER_ALG_RESULT_DATA])
+            .await
+            .ok();
+
+        let data_written = if let Some(()) = address_written {
+            i2c.read_async(CCS811_I2C_ADDRESS, &mut measured_value_buffer)
+                .await
+                .ok()
+        } else {
+            None
+        };
+
+        let measured_value = if let Some(()) = data_written {
+            Some(u16::from_be_bytes(measured_value_buffer))
+        } else {
+            None
+        };
+
+        info!(
+            "Reported status: {}\tMeasured value: {}",
+            status, measured_value
+        );
+
+        Timer::after(Duration::from_secs(2)).await;
+    }
 }
 
 #[embassy_executor::task]