rpi_led.rs

#![feature(lang_items, asm)]
#![crate_type = "staticlib"]
#![no_std]

const GPIO_BASE: u32 = 0x3F000000;
const GPIO_SET: u32 = 0x3F200020;
const GPIO_CLR: u32 = 0x3F20002C;
const GPIO47: u32 = 0x8000;

fn sleep(value: u32){
	for _ in 1..value {
		unsafe { asm!("");}
	}
}

fn gpio_set(port: u32, enabled: bool) {
	let gpio = GPIO_BASE as *const u32;
	let fun = match enabled {
			true => GPIO_SET as *mut u32,
			false => GPIO_CLR as *mut u32,
	};
	unsafe {
		*(fun) = port;
	}
}


#[no_mangle]
pub extern fn main() {
	loop {
		gpio_set(GPIO47, true);
		sleep(500000);
		gpio_set(GPIO47, false);
		sleep(500000);
	}
}

#[lang = "eh_personality"]
extern fn eh_personality() {}

#[lang = "panic_fmt"]
extern fn panic_fmt() {}
;;; Compile with $ rustc --target arm-unknown-linux-gnueabihf -O --emit=obj kernel.rs
;;; The link with $ arm-none-eabi-gcc -O0 -march=armv7-a -mfpu=neon-vfpv4 -mfloat-abi=hard -nostartfiles kernel.o -o kernel.elf
;;; Then build the image with $ arm-none-eabi-objcopy kernel.elf -O binary kernel.img 

Gershuan, you should see the RaspberryPi Resources section.