Add RNG

.github/workflows/ci.yml

@@ -23,6 +23,8 @@ jobs:
         logger:
           - log
           - defmt
+        features:
+          - rand
     env:                        # Peripheral Feature flags
       FLAGS: rt
 
@@ -45,6 +47,6 @@ jobs:
       - name: Install thumbv8m rust target
         run: rustup target add thumbv8m.main-none-eabihf
       - name: Build
-        run: cargo build --verbose --release --examples --target thumbv8m.main-none-eabihf --features ${{ matrix.mcu }},${{ matrix.logger }},${{ env.FLAGS }}
+        run: cargo build --verbose --release --examples --target thumbv8m.main-none-eabihf --features ${{ matrix.mcu }},${{ matrix.features }},${{ matrix.logger }},${{ env.FLAGS }}
       - name: Test
-        run: cargo test --lib --target x86_64-unknown-linux-gnu --features ${{ matrix.mcu }},${{ matrix.logger }},${{ env.FLAGS }}
+        run: cargo test --lib --target x86_64-unknown-linux-gnu --features ${{ matrix.mcu }},${{ matrix.features }},${{ matrix.logger }},${{ env.FLAGS }}

Cargo.toml

@@ -42,6 +42,8 @@ ethernet = []               # Only STM32H563/73 have ethernet
 otfdec = []                 # Only STM32H573/33 have OTFDEC
 sdmmc2 = []                 # Only STM32H563/73 have SDMMC2
 
+rand = ["dep:rand_core"]
+
 rt = ["stm32h5/rt"]
 stm32h503 = ["stm32h5/stm32h503", "device-selected", "rm0492"]
 stm32h523 = ["stm32h5/stm32h523", "device-selected", "rm0481", "h523_h533"]
@@ -64,6 +66,7 @@ embedded-hal = "1.0.0"
 defmt = { version = "1.0.0", optional = true }
 paste = "1.0.15"
 log = { version = "0.4.20", optional = true}
+rand_core = { version = "0.6", default-features = false, optional = true }
 
 [dev-dependencies]
 log = { version = "0.4.20"}

examples/blinky_random.rs

@@ -0,0 +1,72 @@
+// Note: Code taken from stm32h7xx-hal
+//! This example toggles the Pin PA5 with a randomly generated period between 0
+//! and 200 milliseconds. The random period is generated by the internal
+//! hardware random number generator.
+
+#![deny(warnings)]
+#![no_main]
+#![no_std]
+
+use cortex_m_rt::entry;
+use embedded_hal::delay::DelayNs;
+use stm32h5xx_hal::{delay::Delay, pac, prelude::*};
+#[macro_use]
+mod utilities;
+
+use log::info;
+
+#[entry]
+fn main() -> ! {
+    utilities::logger::init();
+    let cp = cortex_m::Peripherals::take().unwrap();
+    let dp = pac::Peripherals::take().expect("cannot take peripherals");
+
+    // Constrain and Freeze power
+    info!("Setup PWR...                  ");
+    let pwr = dp.PWR.constrain();
+    let pwrcfg = pwr.vos0().freeze();
+
+    // Constrain and Freeze clock
+    info!("Setup RCC...                  ");
+    let rcc = dp.RCC.constrain();
+    //let ccdr = rcc.sys_ck(100.MHz()).freeze(pwrcfg, &dp.SYSCFG);
+    let ccdr = rcc.sys_ck(100.MHz()).freeze(pwrcfg, &dp.SBS);
+
+    info!("");
+    info!("stm32h5xx-hal example - Random Blinky");
+    info!("");
+
+    let gpioa = dp.GPIOA.split(ccdr.peripheral.GPIOA);
+
+    // Configure PA5 as output.
+    let mut led = gpioa.pa5.into_push_pull_output();
+
+    // Get the delay provider.
+    let mut delay = Delay::new(cp.SYST, &ccdr.clocks);
+
+    // Get true random number generator
+    let mut rng = dp.RNG.rng(ccdr.peripheral.RNG, &ccdr.clocks);
+    let mut random_bytes = [0u16; 3];
+    match rng.fill(&mut random_bytes) {
+        Ok(()) => info!("random bytes: {:?}", random_bytes),
+        Err(err) => info!("RNG error: {:?}", err),
+    }
+
+    loop {
+        let random_element: Result<u32, _> = rng.gen();
+
+        match random_element {
+            Ok(random) => {
+                // NOTE: the result of the expression `random % 200`
+                // is biased. This bias is called "modulo-bias". It is
+                // acceptable here for simplicity, but may not be
+                // acceptable for your application.
+                let period = random % 200_u32;
+
+                led.toggle();
+                delay.delay_ms(period);
+            }
+            Err(err) => info!("RNG error: {:?}", err),
+        }
+    }
+}

src/lib.rs

@@ -73,6 +73,9 @@ pub mod icache;
 #[cfg(feature = "device-selected")]
 pub mod delay;
 
+#[cfg(feature = "device-selected")]
+pub mod rng;
+
 #[cfg(feature = "device-selected")]
 mod sealed {
     pub trait Sealed {}

src/prelude.rs

@@ -7,5 +7,6 @@ pub use crate::icache::ICacheExt as _stm32h5xx_hal_icache_ICacheExt;
 pub use crate::pwr::PwrExt as _stm32h5xx_hal_pwr_PwrExt;
 pub use crate::rcc::RccExt as _stm32h5xx_hal_rcc_RccExt;
 
+pub use crate::rng::{RngCore as _, RngExt as _};
 pub use crate::time::U32Ext as _;
 pub use fugit::{ExtU32 as _, RateExtU32 as _};