.syntax unified .cpu cortex-m3 .thumb .section .text .global vectors vectors: .align 2 .word 0 .word _start .thumb_func .global _start _start: /* enable port C clock */ ldr r0, =0x40021000 ldr r1, [r0, #0x18] mov r2, #5 orr r1, r2 str r1, [r0, #0x18] /* * enable output mode at a max of 2 MHz. * note that the default is a general purpose output push-pull, * which is what it should be. */ ldr r0, =0x40011000 ldr r1, [r0, #0x04] mov r2, #0x02 lsl r2, #0x14 orr r1, r2 str r1, [r0, #0x04] /* write LED pin (PC13) */ ldr r0, =0x40011000 ldr r1, [r0, #0x10] mov r2, #0x01 lsl r2, #0x0d lsl r2, #0x10 orr r1, r2 str r1, [r0, #0x10] hang: bl .