feat: lab06 (#14)

* feat: lab06

Signed-off-by: Eva Cosma <eva.cosma.mail@gmail.com>

* feat: lab06 clarifying comments

Signed-off-by: Eva Cosma <eva.cosma.mail@gmail.com>

---------

Signed-off-by: Eva Cosma <eva.cosma.mail@gmail.com>

Author: eva-cosma

Cargo.lock

@@ -1,6 +1,6 @@
 [workspace]
 resolver = "3"
-members = ["lab01", "lab02", "lab03", "lab04", "lab05"]
+members = ["lab01", "lab02", "lab03", "lab04", "lab05", "lab06"]
 
 [workspace.dependencies]
 # Low level access to Cortex-M processors

Cargo.toml

@@ -0,0 +1,8 @@
+[build]
+target = "thumbv8m.main-none-eabihf"
+
+[target.'cfg(all(target_arch = "arm", target_os = "none"))']
+runner = "probe-rs run --chip STM32U545RETxQ"
+
+[env]
+DEFMT_LOG = "debug"

lab06/.cargo/config.toml

@@ -0,0 +1,32 @@
+[package]
+name = "lab06"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+# Low level access to Cortex-M processors
+cortex-m.workspace = true
+# Boostrap crate for Cortex-M Processors
+cortex-m-rt.workspace = true
+# Defmt support
+defmt.workspace = true
+defmt-rtt.workspace = true
+# Embedded HAL utilities
+embassy-embedded-hal.workspace = true
+# Async/await executor
+embassy-executor.workspace = true
+# Utilities for working with futures, compatible with no_std and not using alloc
+embassy-futures.workspace = true
+# STM32 HAL Implementation
+embassy-stm32.workspace = true
+# Synchronization primitives and data structures with async support
+embassy-sync.workspace = true
+# Timekeeping, delays and timeouts
+embassy-time.workspace = true
+embedded-graphics = "0.8.1"
+embedded-hal = "1.0.0"
+embedded-hal-async = "1.0.0"
+heapless = "0.9.2"
+mipidsi = "0.9.0"
+# Panic handler that exits `probe-run` with an error code
+panic-probe.workspace = true

lab06/Cargo.toml

@@ -0,0 +1,46 @@
+//! This build script copies the `memory.x` file from the crate root into
+//! a directory where the linker can always find it at build time.
+//! For many projects this is optional, as the linker always searches the
+//! project root directory -- wherever `Cargo.toml` is. However, if you
+//! are using a workspace or have a more complicated build setup, this
+//! build script becomes required. Additionally, by requesting that
+//! Cargo re-run the build script whenever `memory.x` is changed,
+//! updating `memory.x` ensures a rebuild of the application with the
+//! new memory settings.
+
+// use std::env;
+// use std::fs::File;
+// use std::io::Write;
+// use std::path::PathBuf;
+
+fn main() {
+    // This section is not needed as the `embassy-stm32` crate
+    // provides `memory.x` and adds it to the linker's path.
+    //
+    // If using a crate that does not provide it, please
+    // uncomment the this section and the related imported
+    // items.
+
+    // Put `memory.x` in our output directory and ensure it's
+    // on the linker search path.
+    // let out = &PathBuf::from(env::var_os("OUT_DIR").unwrap());
+    // File::create(out.join("memory.x"))
+    //     .unwrap()
+    //     .write_all(include_bytes!("memory.x"))
+    //     .unwrap();
+    // println!("cargo:rustc-link-search={}", out.display());
+
+    // By default, Cargo will re-run a build script whenever
+    // any file in the project changes. By specifying `memory.x`
+    // here, we ensure the build script is only re-run when
+    // `memory.x` is changed.
+    // println!("cargo:rerun-if-changed=memory.x");
+
+    // Prevent the linker from page aligning segments
+    println!("cargo:rustc-link-arg-bins=--nmagic");
+
+    // Required for `cortex-m`
+    println!("cargo:rustc-link-arg-bins=-Tlink.x");
+    // Required for `defmt`
+    println!("cargo:rustc-link-arg-bins=-Tdefmt.x");
+}

lab06/build.rs

@@ -0,0 +1,79 @@
+#![no_std]
+#![no_main]
+
+use defmt::info;
+use defmt_rtt as _;
+use embassy_executor::Spawner;
+use embassy_stm32::{
+    bind_interrupts,
+    i2c::{self, I2c},
+    peripherals,
+};
+use embassy_time::Timer;
+use panic_probe as _;
+
+// For I2C to work, we need to bind the interrupts to the correct handlers.
+bind_interrupts!(struct Irqs {
+    I2C1_EV => i2c::EventInterruptHandler<peripherals::I2C1>;
+    I2C1_ER => i2c::ErrorInterruptHandler<peripherals::I2C1>;
+});
+
+/// The lowest I2C address a device can have. Addresses below this are reserved
+/// for special purposes.
+const LOWEST_I2C_ADDR: u8 = 0x08;
+/// The highest I2C address a device can have. Addresses above this are reserved
+/// for special purposes.
+const HIGHEST_I2C_ADDR: u8 = 0x77;
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    // Initialize the device peripherals
+    let peripherals = embassy_stm32::init(Default::default());
+    info!("Device started");
+
+    // Define the I2C pins. In this lab we will use the I2C1 peripheral, which
+    // is connected to PB6 (SCL) and PB7 (SDA).
+    let scl = peripherals.PB6;
+    let sda = peripherals.PB7;
+
+    // I2C definition
+    let mut i2c = I2c::new(
+        peripherals.I2C1,
+        scl,
+        sda,
+        Irqs,
+        peripherals.GPDMA1_CH0,
+        peripherals.GPDMA1_CH1,
+        Default::default(),
+    );
+
+    // Scan the I2C bus for devices. We do this by trying to read from each
+    // possible address.
+
+    for addr in LOWEST_I2C_ADDR..=HIGHEST_I2C_ADDR {
+        // To execute a "scan", we can either try to execute a read directly, or
+        // we can write a dummy register (0x00) and then wait for a response
+        //
+        // The first approach (read-only) may work with some devices, but it may
+        // not work devices which decide to ignore read requests without a
+        // preceding write. It will also take longer to get a timeout, which
+        // will make the scan take longer to complete.
+        //
+        // The second approach (write-read) is more likely to work with a wider
+        // range of devices, but it is not guaranteed that all devices will have
+        // a `0x00` register.
+        //
+        // For this lab, the BMP390 has its chip ID register at `0x00`, and the
+        // AT24C256 has its first memory address at `0x00`.
+        let mut rx_buf = [0u8; 1];
+        let res = i2c.write_read(addr, &[0x00], &mut rx_buf).await;
+        info!(
+            "Result for address 0x{:02x}: {:?} | Data: {:?}",
+            addr, res, rx_buf
+        );
+    }
+
+    loop {
+        Timer::after_secs(1).await;
+    }
+}

lab06/src/bin/ex1.rs

@@ -0,0 +1,161 @@
+#![no_std]
+#![no_main]
+
+use defmt::info;
+use defmt_rtt as _;
+use embassy_executor::Spawner;
+use embassy_stm32::{
+    bind_interrupts,
+    i2c::{self, I2c},
+    peripherals,
+};
+use embassy_time::Timer;
+use panic_probe as _;
+
+// For I2C to work, we need to bind the interrupts to the correct handlers.
+bind_interrupts!(struct Irqs {
+    I2C1_EV => i2c::EventInterruptHandler<peripherals::I2C1>;
+    I2C1_ER => i2c::ErrorInterruptHandler<peripherals::I2C1>;
+});
+
+/// I2C device address for the BMP390. This is the default address when A0 is
+/// connected to low. If A0 is connected to high, the address will be 0x77.
+///
+/// This will likely work even if A0 is not connected at all, in theory this
+/// should be a "floating" pin, but in practice for our PM Lab board it will
+/// function as if it were connected to low.
+const BMP390_ADDR: u8 = 0x76;
+
+/// Register addresses and values for the `PWR_CTRL` register. (Turns on and off
+/// measurements and sets the power mode.)
+///
+/// | Bits | Description                                     |
+/// |------|-------------------------------------------------|
+/// | 0    | Pressure measurement on/off. 1 = on, 0 = off    |
+/// | 1    | Temperature measurement on/off. 1 = on, 0 = off |
+/// | 2-3  | Reserved, must be set to 0                      |
+/// | 4-5  | Power mode. 00 = sleep, 01/10 = forced (one
+///          measurement), 11 = normal                       |
+/// | 6-7  | Reserved, must be set to 0                      |
+const REGISTER_PWR_CTRL: u8 = 0x1B;
+/// Bits to set in the `PWR_CTRL` register to set normal power mode.
+const PWR_MODE_ON: u8 = 0b0011_0000;
+/// Bits to set in the `PWR_CTRL` register to enable temperature measurement.
+const PWR_TEMP_EN: u8 = 0b0000_0010;
+/// Value to write to the `PWR_CTRL` register to enable temperature measurement
+/// and set normal power mode.
+const PWR_VAL: u8 = PWR_MODE_ON | PWR_TEMP_EN;
+
+/// Register addresses and values for the `OSR` register. (Controls how many
+/// samples are taken and averaged for each measurement)
+///
+/// | Bits | Description                                     |
+/// |------|-------------------------------------------------|
+/// | 0-2  | Pressure oversampling.
+///         000 = no oversampling (1 sample),
+///         001 = x2 (2 samples),
+///         010 = x4 (4 samples),
+///         011 = x8 (8 samples),
+///         100 = x16 (16 samples),   
+///         101 = x32 (32 samples),                          |
+/// | 3-5  | Temperature oversampling.
+///         000 = no oversampling (1 sample),
+///         001 = x2 (2 samples),
+///         010 = x4 (4 samples),
+///         011 = x8 (8 samples),
+///         100 = x16 (16 samples),
+///         101 = x32 (32 samples),                          |
+/// | 6-7  | Reserved, must be set to 0                      |
+const REGISTER_OSR: u8 = 0x1C;
+/// Bits to set in the `OSR` register to set temperature oversampling to x2.
+const OSR_TEMP_X2: u8 = 0b0000_1000;
+/// Value to write to the `OSR` register to set temperature oversampling to x2
+/// and pressure oversampling to none.
+const OSR_VAL: u8 = OSR_TEMP_X2;
+
+/// Register addresses for the raw temperature data (Least significant bits).
+const REGISTER_TEMP_XLSB: u8 = 0x07;
+/// Register addresses for the raw temperature data (Middle significant bits).
+const REGISTER_TEMP_LSB: u8 = 0x08;
+/// Register addresses for the raw temperature data (Most significant bits).
+const REGISTER_TEMP_MSB: u8 = 0x09;
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    // Initialize the device peripherals
+    let peripherals = embassy_stm32::init(Default::default());
+    info!("Device started");
+
+    // Define the I2C pins. In this lab we will use the I2C1 peripheral, which
+    // is connected to PB6 (SCL) and PB7 (SDA).
+    let scl = peripherals.PB6;
+    let sda = peripherals.PB7;
+
+    // I2C definition
+    let mut i2c = I2c::new(
+        peripherals.I2C1,
+        scl,
+        sda,
+        Irqs,
+        peripherals.GPDMA1_CH0,
+        peripherals.GPDMA1_CH1,
+        Default::default(),
+    );
+
+    // Before we can read any data from the sensor, we need to configure the power.
+    i2c.write(BMP390_ADDR, &[REGISTER_PWR_CTRL, PWR_VAL])
+        .await
+        .unwrap();
+
+    // And we also need to configure the oversampling settings.
+    i2c.write(BMP390_ADDR, &[REGISTER_OSR, OSR_VAL])
+        .await
+        .unwrap();
+
+    // Read the raw temperature data. There are 2 ways we can do this.
+    loop {
+        // The first way is to read all 3 bytes in one go. Since the registers
+        // are consecutige, the BMP automatically increments the register
+        // address after each byte, so we can just read from the first register,
+        // and so long as we have more bytes to read, the main (us, the MCU)
+        // will send ACK to continue reading. After we read the last byte (as
+        // determined by the size of the array), we will send a NACK indicating
+        // to the BMP that we are done reading. This will ensure that the
+        // temperature data is consistent.
+        let mut raw_temp_data = [0u8; 3];
+        i2c.write_read(BMP390_ADDR, &[REGISTER_TEMP_XLSB], &mut raw_temp_data)
+            .await
+            .unwrap();
+
+        // Alternatively, we can read each byte one by one. This is more likely
+        // to cause inconsistent data, since the BMP may update the temperature
+        // data in between our reads, but it is still possible to get the
+        // correct data if we are lucky.
+        let mut raw_xlsb = [0u8; 1];
+        let mut raw_lsb = [0u8; 1];
+        let mut raw_msb = [0u8; 1];
+        i2c.write_read(BMP390_ADDR, &[REGISTER_TEMP_XLSB], &mut raw_xlsb)
+            .await
+            .unwrap();
+        i2c.write_read(BMP390_ADDR, &[REGISTER_TEMP_LSB], &mut raw_lsb)
+            .await
+            .unwrap();
+        i2c.write_read(BMP390_ADDR, &[REGISTER_TEMP_MSB], &mut raw_msb)
+            .await
+            .unwrap();
+
+        info!("Raw data: {:?}", raw_temp_data);
+        info!(
+            "Raw byte by byte: {:?}",
+            [raw_xlsb[0], raw_lsb[0], raw_msb[0]]
+        );
+
+        // The raw temperature data is a 24-bit signed integer
+        let raw_temp: i32 = ((raw_temp_data[2] as i32) << 16)
+            | ((raw_temp_data[1] as i32) << 8)
+            | (raw_temp_data[0] as i32);
+        info!("Raw temperature value: {}", raw_temp);
+
+        Timer::after_millis(400).await;
+    }
+}