ASM_LED 代码
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- GPFCON EQU 0x56000050
- GPFDAT EQU 0x56000054
- GPFUP EQU 0x56000058
- EXPORT ledtest
- AREA LEDTESTASM,CODE,READONLY ;代码段,只读属性
- ledtest
- ldr r0,=GPFCON ;设置GPF4-7为output
- ldr r1,[r0]
- bic r1,r1,#0xff00
- orr r1,r1,#0x5500
- str r1,[r0]
- ldr r0,=GPFUP
- ldr r1,[r0];
- orr r1,r1,#0xf0
- str r1,[r0]
- looptest
- ldr r2,=GPFDAT
- ldr r3,[r2]
- bic r3,r3,#0xf0
- orr r3,r3,#0xb0 ;10110000
- str r3,[r2]
- ldr r0,=0xffffff
- bl delay
- ldr r2,=GPFDAT
- ldr r3,[r2]
- bic r3,r3,#0xf0
- orr r3,r3,#0xd0 ;11010000
- str r3,[r2]
- ldr r0,=0xffffff
- bl delay
- ldr r2,=GPFDAT
- ldr r3,[r2]
- bic r3,r3,#0xf0
- orr r3,r3,#0x70 ;01110000
- str r3,[r2]
- ldr r0,=0xffffff
- bl delay
- ldr r2,=GPFDAT
- ldr r3,[r2]
- bic r3,r3,#0xf0
- orr r3,r3,#0xe0 ;11100000
- str r3,[r2]
- ldr r0,=0xffffff
- bl delay
- bl looptest
- delay
- sub r0,r0,#1 ;r0=r0-1
- cmp r0,#0x0
- bne delay
- mov pc,lr ; 返回
- end