From 3ef62eef5370b34792a737dd5a4b296fe3fd8c7d Mon Sep 17 00:00:00 2001
From: Felipe Balbi <febalbi@microsoft.com>
Date: Thu, 16 May 2024 08:12:18 -0700
Subject: [PATCH] stm32h7: add shared bus example

---
 examples/stm32h7/Cargo.toml            |   1 +
 examples/stm32h7/src/bin/i2c_shared.rs | 112 +++++++++++++++++++++++++
 2 files changed, 113 insertions(+)
 create mode 100644 examples/stm32h7/src/bin/i2c_shared.rs

diff --git a/examples/stm32h7/Cargo.toml b/examples/stm32h7/Cargo.toml
index a09af4b97..c6c2d1354 100644
--- a/examples/stm32h7/Cargo.toml
+++ b/examples/stm32h7/Cargo.toml
@@ -8,6 +8,7 @@ license = "MIT OR Apache-2.0"
 # Change stm32h743bi to your chip name, if necessary.
 embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["defmt", "stm32h743bi", "time-driver-tim2", "exti", "memory-x", "unstable-pac", "chrono"] }
 embassy-sync = { version = "0.5.0", path = "../../embassy-sync", features = ["defmt"] }
+embassy-embedded-hal = { version = "0.1.0", path = "../../embassy-embedded-hal" }
 embassy-executor = { version = "0.5.0", path = "../../embassy-executor", features = ["task-arena-size-32768", "arch-cortex-m", "executor-thread", "executor-interrupt", "defmt", "integrated-timers"] }
 embassy-time = { version = "0.3.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-hz-32_768"] }
 embassy-net = { version = "0.4.0", path = "../../embassy-net", features = ["defmt", "tcp", "dhcpv4", "medium-ethernet", "proto-ipv6", "dns"] }
diff --git a/examples/stm32h7/src/bin/i2c_shared.rs b/examples/stm32h7/src/bin/i2c_shared.rs
new file mode 100644
index 000000000..79d213ae4
--- /dev/null
+++ b/examples/stm32h7/src/bin/i2c_shared.rs
@@ -0,0 +1,112 @@
+#![no_std]
+#![no_main]
+
+use core::cell::RefCell;
+
+use defmt::*;
+use embassy_embedded_hal::shared_bus::blocking::i2c::I2cDevice;
+use embassy_executor::Spawner;
+use embassy_stm32::bind_interrupts;
+use embassy_stm32::i2c::{self, I2c};
+use embassy_stm32::mode::Async;
+use embassy_stm32::peripherals::{self, I2C1};
+use embassy_stm32::time::Hertz;
+use embassy_sync::blocking_mutex::NoopMutex;
+use embassy_time::{Duration, Timer};
+use static_cell::StaticCell;
+use {defmt_rtt as _, panic_probe as _};
+
+const TMP117_ADDR: u8 = 0x48;
+const TMP117_TEMP_RESULT: u8 = 0x00;
+
+const SHTC3_ADDR: u8 = 0x70;
+const SHTC3_WAKEUP: [u8; 2] = [0x35, 0x17];
+const SHTC3_MEASURE_RH_FIRST: [u8; 2] = [0x5c, 0x24];
+const SHTC3_SLEEP: [u8; 2] = [0xb0, 0x98];
+
+static I2C_BUS: StaticCell<NoopMutex<RefCell<I2c<'static, I2C1, Async>>>> = StaticCell::new();
+
+bind_interrupts!(struct Irqs {
+    I2C1_EV => i2c::EventInterruptHandler<peripherals::I2C1>;
+    I2C1_ER => i2c::ErrorInterruptHandler<peripherals::I2C1>;
+});
+
+#[embassy_executor::task]
+async fn temperature(mut i2c: impl embedded_hal_1::i2c::I2c + 'static) {
+    let mut data = [0u8; 2];
+
+    loop {
+        match i2c.write_read(TMP117_ADDR, &[TMP117_TEMP_RESULT], &mut data) {
+            Ok(()) => {
+                let temp = f32::from(i16::from_be_bytes(data)) * 7.8125 / 1000.0;
+                info!("Temperature {}", temp);
+            }
+            Err(_) => error!("I2C Error"),
+        }
+
+        Timer::after(Duration::from_millis(1000)).await;
+    }
+}
+
+#[embassy_executor::task]
+async fn humidity(mut i2c: impl embedded_hal_1::i2c::I2c + 'static) {
+    let mut data = [0u8; 6];
+
+    loop {
+        // Wakeup
+        match i2c.write(SHTC3_ADDR, &SHTC3_WAKEUP) {
+            Ok(()) => Timer::after(Duration::from_millis(20)).await,
+            Err(_) => error!("I2C Error"),
+        }
+
+        // Measurement
+        match i2c.write(SHTC3_ADDR, &SHTC3_MEASURE_RH_FIRST) {
+            Ok(()) => Timer::after(Duration::from_millis(5)).await,
+            Err(_) => error!("I2C Error"),
+        }
+
+        // Result
+        match i2c.read(SHTC3_ADDR, &mut data) {
+            Ok(()) => Timer::after(Duration::from_millis(5)).await,
+            Err(_) => error!("I2C Error"),
+        }
+
+        // Sleep
+        match i2c.write(SHTC3_ADDR, &SHTC3_SLEEP) {
+            Ok(()) => {
+                let (bytes, _) = data.split_at(core::mem::size_of::<i16>());
+                let rh = f32::from(u16::from_be_bytes(bytes.try_into().unwrap())) * 100.0 / 65536.0;
+                info!("Humidity: {}", rh);
+            }
+            Err(_) => error!("I2C Error"),
+        }
+
+        Timer::after(Duration::from_millis(1000)).await;
+    }
+}
+
+#[embassy_executor::main]
+async fn main(spawner: Spawner) {
+    let p = embassy_stm32::init(Default::default());
+
+    let i2c = I2c::new(
+        p.I2C1,
+        p.PB8,
+        p.PB9,
+        Irqs,
+        p.DMA1_CH4,
+        p.DMA1_CH5,
+        Hertz(100_000),
+        Default::default(),
+    );
+    let i2c_bus = NoopMutex::new(RefCell::new(i2c));
+    let i2c_bus = I2C_BUS.init(i2c_bus);
+
+    // Device 1, using embedded-hal-async compatible driver for TMP117
+    let i2c_dev1 = I2cDevice::new(i2c_bus);
+    spawner.spawn(temperature(i2c_dev1)).unwrap();
+
+    // Device 2, using embedded-hal-async compatible driver for SHTC3
+    let i2c_dev2 = I2cDevice::new(i2c_bus);
+    spawner.spawn(humidity(i2c_dev2)).unwrap();
+}