Enable GPIO Pull Up and Down

src/main.rs

@@ -21,6 +21,7 @@ fn panic(_panic: &PanicInfo) -> ! {
 #[no_mangle]
 #[link_section = ".text._start"]
 pub unsafe extern "C" fn _start() {
+    // Set the stack pointer
     asm!("ldr x0, =0x8004000", "mov sp, x0");
     main();
 }
@@ -29,19 +30,25 @@ pub unsafe extern "C" fn _start() {
 extern "C" fn main() {
     uart::configure_uart();
     unsafe {
+        // Set ACT Led to Outout
         let _ = set_gpio_state(29, gpio::GPIOState::Output);
+
+        // Set GPIO Pins to UART
         let _ = set_gpio_state(14, gpio::GPIOState::Alternative0);
         let _ = set_gpio_state(15, gpio::GPIOState::Alternative0);
     }
 
     // Delay so clock speed can stabilize
-    unsafe { delay_nops(50000) }
+    delay_nops(50000);
     uart::print("Hello World!\n");
 
+    sleep(500_000);
+
     loop {
         let _ = gpio_high(29);
-        unsafe { sleep(500_000) } // 0.5s
+
+        sleep(500_000); // 0.5s
         let _ = gpio_low(29);
-        unsafe { sleep(500_000) } // 0.5s
+        sleep(500_000) // 0.5s
     }
 }