开发板点灯实验源码

/* ========== start.s 启动汇编 ========== */
.global _start

_start:
ldr sp, =0xFFFF0000
bl main
halt:
b halt
/* ========== led.c 主C代码 ==========/
#define GPIOEOUTENB ((volatile unsigned int)0xC001E004)
#define GPIOEOUT ((volatile unsigned int *)0xC001E000)

void delay(void)
{
volatile unsigned int i = 0xf00000;
for(; i > 0; i–);
}

int main(void)
{
unsigned int cnt = 0x2000;
GPIOEOUTENB |= (1U << 13);

while (cnt--) { GPIOEOUT &= ~(1U << 13); delay(); GPIOEOUT |= (1U << 13); delay(); } while(1);

}
/* ========== led.lds 链接脚本 ========== */
SECTIONS
{
. = 0xC0000000;
.text : {
*(.text)
}
.rodata : {
*(.rodata)
}
.data : {
*(.data)
}
.bss : {
*( .bss )
}
}

========== 交叉编译命令 ==========

arm-linux-gnueabihf-as start.s -o start.o
arm-linux-gnueabihf-gcc -c led.c -o led.o -nostdlib
arm-linux-gnueabihf-ld start.o led.o -T led.lds -o led.elf
arm-linux-gnueabihf-objcopy -O binary led.elf led.bin