Merge branch 'master' of gitlab.henriktjader.com:pln/rtfm-app

examples/clk_out_itm.rs

+//! Simple access to gpio
+//#![deny(unsafe_code)]
+#![feature(proc_macro)]
+#![no_std]
+
+extern crate cortex_m;
+extern crate cortex_m_rtfm as rtfm;
+extern crate stm32f40x;
+
+#[macro_use]
+extern crate cortex_m_debug;
+use rtfm::app;
+
+app! {
+    device: stm32f40x,
+}
+
+fn wait(i: u32) {
+    for _ in 0..i {
+        cortex_m::asm::nop(); // no operation (cannot be optimized out)
+    }
+}
+
+// see the Reference Manual RM0368 (www.st.com/resource/en/reference_manual/dm00096844.pdf)
+// rcc,     chapter 6
+// gpio,    chapter 8
+
+fn init(p: init::Peripherals) {
+    ipln!("OUTPUT MCO2 on PC9/CN10-1)");
+    sprintln!("OUTPUT MCO2 on PC9/CN10-1)");
+    // output MCO2 to pin PC9
+    //
+
+    // mco2 	: SYSCLK = 0b00
+    // mcopre 	: divide by 4 = 0b110
+    p.RCC
+        .cfgr
+        .modify(|_, w| unsafe { w.mco2().bits(0b00).mco2pre().bits(0b110) });
+
+    // power on GPIOC, RM0368 6.3.11
+    p.RCC.ahb1enr.modify(|_, w| w.gpiocen().set_bit());
+
+    // MCO_2 alternate function AF0, STM32F401xD STM32F401xE data sheet
+    // table 9
+    // AF0, gpioc reset value = AF0
+
+    // configure PC9 as alternate function 0b10, RM0368 6.2.10
+    p.GPIOC
+        .moder
+        .modify(|_, w| unsafe { w.moder9().bits(0b10) });
+
+    // otyper reset state push/pull
+
+    // ospeedr 0b11 = high speed
+    p.GPIOC
+        .ospeedr
+        .modify(|_, w| unsafe { w.ospeedr9().bits(0b11) });
+
+    // power on GPIOA, RM0368 6.3.11
+    p.RCC.ahb1enr.modify(|_, w| w.gpioaen().set_bit());
+
+    // configure PA5 as output, RM0368 8.4.1
+    p.GPIOA.moder.modify(|_, w| w.moder5().bits(1));
+
+    // loop {
+    //     // set PA5 high, RM0368 8.4.6
+    //     p.GPIOA.odr.modify(|_, w| w.odr5().bit(true));
+    //     wait(10_000);
+
+    //     // set PA5 low, RM0368 8.4.6
+    //     p.GPIOA.odr.modify(|_, w| w.odr5().bit(false));
+    //     wait(10_000);
+    // }
+
+    // rewrite the above code to have the GPIO as output
+    // and alter the data output through the BSRR register
+    // this is more efficient as the read register (in modify)
+    // is not needed.
+
+    loop {
+        // set PA5 high, RM0368 8.4.7
+        p.GPIOA.bsrr.write(|w| w.bs5().set_bit());
+        wait(10_000);
+
+        // set PA5 low, RM0368 8.4.7
+        p.GPIOA.bsrr.write(|w| w.br5().set_bit());
+        wait(10_000);
+    }
+}
+
+#[inline(never)]
+fn idle() -> ! {
+    loop {
+        rtfm::wfi();
+    }
+}