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stevej/red_led.asm

Created June 11, 2010 04:01
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A simple example of doing memory-mapped IO on an ARM7 (this turns on a Red LED for a UberBoard v2)
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red_led.asm
.equiv GPIO_BASE_ADDR, 0x0E0028000
.equiv IOCLR0, GPIO_BASE_ADDR + 0x0C
.equiv IODIR0, GPIO_BASE_ADDR + 0x08
.equiv RED_LED, 1 << 18
.globl _start
_start:
ldr r1, =IODIR0
ldr r2, =RED_LED
str r2, [r1]
ldr r1, =IOCLR0
ldr r2, =RED_LED
add r2, r2, r1
str r2, [r1]
_loop:
b _loop
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