boards/kakute-f7-mini-v3: simple led demo for board testing

Signed-off-by: Onur Özkan <work@onurozkan.dev>

boards/kakute-f7-mini-v3/src/main.rs

@@ -1,9 +1,10 @@
 #![no_std]
 #![no_main]
 
+use cortex_m_rt as _;
 use panic_halt as _;
 
-#[rtic::app(device = stm32f7::stm32f745, peripherals = true)]
+#[rtic::app(device = stm32f7::stm32f722, peripherals = true)]
 mod app {
     #[shared]
     struct Shared {
@@ -13,11 +14,30 @@ mod app {
     #[local]
     struct Local {
         // TODO
+        led: stm32f7::stm32f722::GPIOD,
+        led_output_high: bool,
     }
 
     #[init]
-    fn init(_context: init::Context) -> (Shared, Local) {
-        (Shared {}, Local {})
+    fn init(context: init::Context) -> (Shared, Local) {
+        let device = context.device;
+
+        device
+            .RCC
+            .ahb1enr()
+            .modify(|_, write| write.gpioden().set_bit());
+        device
+            .GPIOD
+            .moder()
+            .modify(|_, write| write.moder2().output());
+
+        (
+            Shared {},
+            Local {
+                led: device.GPIOD,
+                led_output_high: false,
+            },
+        )
     }
 
     #[task(binds = EXTI4, priority = 15)]
@@ -25,12 +45,25 @@ mod app {
         // TODO
     }
 
-    #[idle]
-    fn idle(_context: idle::Context) -> ! {
-        // TODO
-
+    #[idle(local = [led, led_output_high])]
+    fn idle(context: idle::Context) -> ! {
         loop {
-            cortex_m::asm::wfi();
+            if *context.local.led_output_high {
+                context
+                    .local
+                    .led
+                    .bsrr()
+                    .write(|write| write.br2().set_bit());
+            } else {
+                context
+                    .local
+                    .led
+                    .bsrr()
+                    .write(|write| write.bs2().set_bit());
+            }
+
+            *context.local.led_output_high = !*context.local.led_output_high;
+            cortex_m::asm::delay(8_000_000);
         }
     }
 }