uninit.rs

#[derive(Debug)]
#[repr(C, packed)]
struct LedState {
    on: u16,
    off: u16,
}

#[derive(Debug)]
#[repr(C, packed)]
struct LedArray {
    reg_addr: u8,
    leds: [LedState; 16],
}

#[link_section = ".sram1_bss"]
static mut LED_BUFFER: MaybeUninit<LedArray> = MaybeUninit::uninit();
  
fn main() -> ! {
  // ...
      unsafe {
        LED_BUFFER.as_mut_ptr().write(LedArray {
            reg_addr: 0x06,
            leds: [
                LedState { on: 0, off: 0 },
                LedState { on: 0, off: 0 },
                LedState { on: 0, off: 0 },
                LedState { on: 0, off: 0 },
                LedState { on: 0, off: 0 },
                LedState { on: 0, off: 0xfff },
                LedState { on: 0, off: 0 },
                LedState { on: 0, off: 0 },
                LedState { on: 0, off: 0 },
                LedState { on: 0, off: 0 },
                LedState { on: 0, off: 0x100 },
                LedState { on: 0, off: 0 },
                LedState { on: 0, off: 0 },
                LedState { on: 0, off: 0 },
                LedState { on: 0, off: 0xfff },
                LedState { on: 0, off: 0 },
            ],
        });
     }

  let led_bytes: &LedArray = unsafe { &*LED_BUFFER.as_ptr() };
  rprintln!("len = {:?}", led_bytes);
}