S5PV210有4個向量中斷控制器（VIC），每個向量中斷控制器包含32個中斷源。

當某個中斷源產(chǎn)生中斷時，CPU會自動的將VICxVECTADDRy（x=0,1,2,3,y=0-31）寄存器的值賦給VICxADDRESS（x=0,1,2,3），因此我們可以把我們的中斷處理函數(shù)的地址賦給VICxVECTADDRy寄存器,

比如我們有個函數(shù)

void key_handle()
{?? ?
……
}

我們把key_handle?函數(shù)的值賦給VIC0VECTADDR0（外部中斷0）

VIC0VECTADDR0?=key_handle；

當外部中斷0觸發(fā)中斷時，CPU會自動的將VIC0VECTADDR0的值賦給VIC0ADDRESS，并跳轉(zhuǎn)到這個地址去執(zhí)行，即執(zhí)行函數(shù)key_handle。

代碼如下：

start.S

[cpp]?view plaincopy

.global?_start??????????????????/*?聲明一個全局的標號?*/??

.global?key_isr??

_start:??

????/*?設(shè)置棧，以調(diào)用c函數(shù)?*/??

????ldr?sp,?=0x40000000???????

??

????/*?開總中斷?*/??

????mrs?r0,?cpsr??

????bic?r0,?r0,?#0x00000080?????/*?清楚第7位，IRQ中斷禁止位，寫0使能IRQ?*/??

????msr?cpsr,?r0??

??

????bl?main?????????????????????/*?跳轉(zhuǎn)到C函數(shù)去執(zhí)行?*/??

??

halt:??

????b?halt??

??

key_isr:??

????/*?計算返回地址:PC的值等于當前執(zhí)行的地址+8，當CPU正要執(zhí)行某條指令時（還未執(zhí)行），被中斷，?

????**?這是這條剛要執(zhí)行的指令的地址剛好=PC-4?*/??

????sub?lr,?lr,?#4??

????stmfd?sp!,?{r0-r12,?lr}?????/*?保護現(xiàn)場?*/??

????bl?key_handle??

????/*?恢復現(xiàn)場?*/??

????ldmfd?sp!,?{r0-r12,?pc}^????/*?^表示把spsr恢復到cpsr?*/??

key.c

[cpp]?view plaincopy

#define?GPC0CON?????????????*((volatile?unsigned?int?*)0xE0200060)??

#define?GPC0DAT?????????????*((volatile?unsigned?int?*)0xE0200064)??

??

#define?GPH0CON?????????????*((volatile?unsigned?int?*)0xE0200C00)??

#define?GPH0DAT?????????????*((volatile?unsigned?int?*)0xE0200C04)??

??

#define?EXT_INT_0_CON???????*((volatile?unsigned?int?*)0xE0200E00)??

#define?EXT_INT_0_MASK??????*((volatile?unsigned?int?*)0xE0200F00)??

??

#define?VIC0INTSELECT???????*((volatile?unsigned?int?*)0xF200000C)??

#define?VIC0INTENABLE???????*((volatile?unsigned?int?*)0xF2000010)??

??

#define?VIC0VECTADDR0???????*((volatile?unsigned?int?*)0xF2000100)??

#define?VIC0VECTADDR1???????*((volatile?unsigned?int?*)0xF2000104)??

??

#define?VIC0ADDRESS?????????*((volatile?unsigned?int?*)0xF2000F00)??

??

#define?EXT_INT_0_PEND??????*((volatile?unsigned?int?*)0xE0200F40)??

??

extern?void?key_isr(void);??

??

void?key_handle()??

{?????

????volatile?unsigned?char?key_code?=?EXT_INT_0_PEND?&?0x3;??

??????

????VIC0ADDRESS?=?0;????????/*?清中斷向量寄存器?*/??

????EXT_INT_0_PEND?|=?3;????/*?清中斷掛起寄存器?*/??

??????

????if?(key_code?==?1)??????/*?key1?*/??

????????GPC0DAT?^=?1?<<?3;????/*?toggle?LED1?*/??

????else?if?(key_code?==?2)?/*?key2?*/??

????????GPC0DAT?^=?1?<<?4;????/*?toggle?LED2?*/??

}??

??

int?main()??

{??

????GPC0CON?&=?~(0xFF?<<?12);??

????GPC0CON?|=?0x11?<<?12;????????????????????/*?配置GPC0_3和GPC0_4為輸出：LED1和LED2?*/??

????GPH0CON?|=?0xFF?<<?0;?????????????????/*?配置GPH0_0和GPH0_1為外部中斷：key1和key2?*/??

??????

????EXT_INT_0_CON?&=?~(0xFF?<<?0);??

????EXT_INT_0_CON?|=?2?|?(2?<<?4);????????????/*?配置EXT_INT[0]和EXT_INT[1]為下降沿觸發(fā)?*/??

????EXT_INT_0_MASK?&=?~3;???????????????????/*?取消屏蔽外部中斷EXT_INT[0]和EXT_INT[1]?*/??

??????

????VIC0INTSELECT?&=?~3;????????????????????/*?選擇外部中斷EXT_INT[0]和外部中斷EXT_INT[1]為IRQ類型的中斷?*/??

??????

????VIC0INTENABLE?|=?3;?????????????????????/*?使能外部中斷EXT_INT[0]和EXT_INT[1]?*/??

??????

????VIC0VECTADDR0?=?(int)key_isr;???????????/*?當EXT_INT[0]觸發(fā)中斷，即用戶按下key1時，?

?????????????????????????????????????????????CPU就會自動的將VIC0VECTADDR0的值賦給VIC0ADDRESS并跳轉(zhuǎn)到這個地址去執(zhí)?*/??

????VIC0VECTADDR1?=?(int)key_isr;??

??????

????while?(1);??

??????

????return?0;??

}??

Makefile

[cpp]?view plaincopy

key.bin:?start.o?key.o??

????arm-linux-ld?-Ttext?0x20000000?-o?key.elf?$^??

????arm-linux-objcopy?-O?binary?key.elf?$@??

????arm-linux-objdump?-D?key.elf?>?key.dis??

??????

key.o?:?key.c??

????arm-linux-gcc?-c?$<?-o?$@??

start.o?:?start.S??

????arm-linux-gcc?-c?$<?-o?$@??

??????

clean:??

????rm?*.o?*.elf?*.bin?*.dis??

將程序下載到內(nèi)存運行

按下key1，LED1點亮，再次按下key1，LED1熄滅

按下key2，LED2點亮，再次按下key2，LED2熄滅

總結(jié)

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