Add simple FLASH API

Author: hannobraun

Cargo.toml

@@ -111,6 +111,10 @@ required-features = ["rt"]
 name = "button_irq_rtfm"
 required-features = ["rt"]
 
+[[example]]
+name = "flash"
+required-features = ["rt","stm32l082"]
+
 [[example]]
 name = "i2c_dma"
 required-features = ["rt","stm32l0x2"]

examples/flash.rs

@@ -0,0 +1,70 @@
+#![no_main]
+#![no_std]
+
+
+extern crate panic_semihosting;
+
+
+use cortex_m_rt::entry;
+use stm32l0xx_hal::{
+    prelude::*,
+    flash::{
+        FLASH,
+        FLASH_START,
+        flash_size_in_kb,
+    },
+    pac,
+    rcc,
+};
+
+
+#[entry]
+fn main() -> ! {
+    let cp = cortex_m::Peripherals::take().unwrap();
+    let dp = pac::Peripherals::take().unwrap();
+
+    let mut rcc   = dp.RCC.freeze(rcc::Config::hsi16());
+    let mut flash = FLASH::new(dp.FLASH, &mut rcc);
+    let     gpiob = dp.GPIOB.split(&mut rcc);
+
+    let mut led = gpiob.pb2.into_push_pull_output();
+
+    // Get the delay provider.
+    let mut delay = cp.SYST.delay(rcc.clocks);
+
+    // This should be the first word in the second flash bank. Since this
+    // example should be quite small, we can be reasonably sure that it fully
+    // fits into the first flash bank. This means we won't overwrite our own
+    // code or stall execution.
+    //
+    // This example requires STM32L082, which has 2 banks.
+    let address = FLASH_START + flash_size_in_kb() / 2 * 1024;
+    let address = address as *mut u32;
+
+    flash.erase_flash_page(address)
+        .expect("Failed to erase Flash page (1)");
+    for i in 0 .. 32 {
+        let word = unsafe { *address.offset(i * 4) };
+        assert_eq!(word, 0);
+    }
+
+    flash.write_word(address, 0x12345678)
+        .expect("Failed to write word");
+    assert_eq!(unsafe { *address }, 0x12345678);
+
+    flash.erase_flash_page(address)
+        .expect("Failed to erase Flash page (2)");
+    for i in 0 .. 32 {
+        let word = unsafe { *address.offset(i * 4) };
+        assert_eq!(word, 0);
+    }
+
+    // Blink LED to indicate we haven't panicked.
+    loop {
+        led.set_high().unwrap();
+        delay.delay_ms(500_u16);
+
+        led.set_low().unwrap();
+        delay.delay_ms(500_u16);
+    }
+}