stm32不用库 裸机点亮led
startup.s 定义栈入口函数 进入main

.syntax unified
.cpu cortex-m3
.fpu softvfp
.thumb.global vtable
.global reset_handler.type vtable, %object
vtable:.word _estack.word reset_handler
.size vtable, .-vtable.section .data
.word _sidata
.word _sdata
.word _edata
.word _sbss
.word _ebss.type reset_handler, %function
reset_handler:ldr r0,=_sdataldr r1,=_edataldr r2,=_sidatabl flash2ramldr r0,=_sbssldr r1,=_ebssbl zerobssbl mainloop:b   loop  //死循环
.size reset_handler, .-reset_handler

main.c

void flash2ram(register unsigned int *dst, register unsigned int* dst_end, register unsigned int* src)
{while(dst < dst_end)*dst++ = *src++;
}void zerobss(register unsigned int* start, register unsigned int* end)
{while(start < end)*start++ = 0;
}void delay(unsigned int n)
{while(n--);
}int main()
{//RCC_APB2ENR  IOPCEN*((unsigned int*)(0x40021000+0x18)) |= 0x10;   //gpioc clk//gpioc CRL General purpose output push-pull  Output mode, max speed 50 MHz.*((unsigned int *)(0x40011000 +0x00)) &= 0xFFFFF0FF; *((unsigned int*)(0x40011000 +0x00))|= 0x00000300;while(1) {//GPIOC_BSRR  set *((unsigned int *)(0x40011000+0x10)) |= 1<<2;delay(1e6);//GPIOC_BRR  clear *((unsigned int *)(0x40011000+0x14)) |= 1<<2;delay(1e6);}
}

sim.ld

_estack = 0x20005000;MEMORY
{FLASH ( rx )      : ORIGIN = 0x08000000, LENGTH = 256KRAM ( rxw )       : ORIGIN = 0x20000000, LENGTH = 48K
}SECTIONS
{.text :{. = ALIGN(4);*(.text)*(.text*)*(.rodata). = ALIGN(4);} >FLASH_sidata = . ;.data : AT ( _sidata ){. = ALIGN(4);_sdata = .;*(.data)*(.data*). = ALIGN(4);_edata = .;} >RAM.bss :{. = ALIGN(4);_sbss = .;*(.bss)*(.bss*)*(COMMON). = ALIGN(4);_ebss = .;} >RAM
}

编译

arm-none-eabi-gcc -mcpu=cortex-m3 -mthumb  --specs=nosys.specs -nostdlib -T sim.ld main.c startup.s -o led.elf

转binary

arm-none-eabi-objcopy -O binary led.elf led.bin

烧录

st-flash write led.bin 0x8000000