在整个ARM体系结构中，为了处理外部中止，顺次学习了MMU，形式跳转，反常，GIC，看门狗程序，这些都是为了处理外部中止
详细如下：
处理外部中止有五个过程：
30 //step 1: cpu cpsr
31 __asm__ __volatile__(
32 “mrs r0, cpsr\n”
33 “bic r0, r0, #0x80\n”//设置CPSR的I位，将IRQ位翻开
34 “msr cpsr, r0\n”
35 ::: “r0”
36 );
37
38 //setp1:GIC
39 ICCICR_CPU0 = 1;
40 ICCPMR_CPU0 = 0xff;
41
前面的代码不解说，和曾经的差不多
外部中止号为：64
42//step2:设置中止号
43 ICDDCR = 1;//总开关
44 ICDIPR16_CPU0 = (0x0 << 0);//ICD总共40个寄存器，第16个寄存器，第0位
45 ICDIPTR16_CPU0 = (0x1 << 0);//优先级，最高
46 %&&&&&%DISER2_CPU0 = (1 << 0);//总共五个，第2个使能中止
47
第二步为设置中止号：
详细看代码注释：寄存器参考手册第594页
48 //step 3: set gpio
49 GPX3CON = (0xf << 8);//是GPXCON为外部中止功用
查看到运用外部中止功用的对应外部寄存器：EXT_INT43：
51 //step 4: extern
52 EXT_INT43CON = (2 << 8);//设置上升沿触发
53 EXT_INT43MASK = 0;//使能中止
设置外部中止操控器：寄存器参考手册第366页
55 //step 5: source
56 外部中止源这儿设置由外部按键K触发：
代码如下
1 #include"regs.h"2 3 int (*printf)(char *, ...) = 0xc3e114d8;4 int(*delay)(int)=0xc3e25f90;5 6 void init_ttb(unsigned long *addr);7 void enable_mmu(void);8 unsigned long data_abort_init();9 void memcopy(unsigned long* dest,unsigned long* source,int len);10 void do_irq();11 void pwm_on(void);12 void pwm_off(void);13 void led_on(void);14 void led_on(void);15 16 int main()17 {18 *(unsigned long *)0x66 = do_irq;19 20 //产生反常时会进入反常形式跳转到0 4地址处理反常事情 21 unsigned long source_addr=data_abort_init();22 //反常事情处理函数23 printf("swi_souce addr is %x\n",source_addr);24 //将反常处理地址的值放到0x6425 memcopy(0x60,source_addr,0x1);26 27 enable_mmu();28 //内存映射将0x04映射到0x6004 29 30 //step 1: cpu cpsr31 __asm__ __volatile__(32 "mrs r0, cpsr\n"33 "bic r0, r0, #0x80\n"//设置CPSR的I位，将IRQ位翻开34 "msr cpsr, r0\n"35 ::: "r0"36 );37 38 //setp1:GIC39 ICCICR_CPU0 = 1;40 ICCPMR_CPU0 = 0xff;41 42 //step1:设置中止号43 ICDDCR = 1;44 ICDIPR16_CPU0 = (0x0 << 0);//ICD第16个寄存器，第0位45 ICDIPTR16_CPU0 = (0x1 << 0);//优先级，最高46 ICDISER2_CPU0 = (1 << 0);//总共五个，第2个使能中止47 48 //step 3: set gpio49 GPX3CON = (0xf << 8);//是GPXCON为外部中止功用50 51 //step 4: extern52 EXT_INT43CON = (2 << 8);//设置上升沿触发53 EXT_INT43MASK = 0;//使能中止54 55 //step 5: source56 //57 printf("welcome back! \n");58 }59 60 void pwm_on(void)61 {62 GPD0CON &= ~0xffff;63 GPD0CON = 0x1;//装备寄存器为264 GPD0DAT = 0x1;//date=0xf65 }66 67 void pwm_off(void)68 {69 GPD0CON &= ~0xffff;70 GPD0CON = 0x0;71 // GPD0DAT &=0x0 ;//date=0xf72 73 }74 void led_off(void)75 {76 GPM4CON &= ~0xffff;//清零77 GPM4CON = 0x0;//03位清零78 GPM4DAT = 0x0;//date=0xf封闭置一79 }80 void led_on(void)81 {82 GPM4CON &= ~0xffff;83 GPM4CON = 0x1;//装备寄存器3-0--3-3全为1，全为输出形式84 GPM4DAT &= ~0xf;//翻开置0-4位为085 }86 87 void do_irq()88 {89 printf("key 1 down\n");90 static int flag=1;91 if(flag)92 {93 printf("wtc_on\n");94 led_on();95 pwm_on();96 flag=0;97 }98 else if(flag == 0)99 {100 printf("wtc_off\n");101 led_off();102 pwm_off();103 flag=1;104 }105 EXT_INT43PEND = (1 << 2);//清中止106 }107 108 void memcopy(unsigned long* dest, unsigned long* source,int len)109 {110 int i=0;;for(i=0;i> 20] = pa 2;210 //2的意图是将0-2方位为10此刻将是小页形式4K211 }212 213 //00-10 ==== 6070214 for(va=0x00; va<=0x10; va+=0x100){215 pa = va+0x60;216 addr[va >> 20] = pa 2;217 }218 219 //10-14 ==== 1014220 for(va=0x10; va<=0x14; va+=0x100){221 pa = va;addr[va >> 20] = pa 2;223 }224 225 //30-40 ==== 5060226 for(va=0x30; va<0x40; va+=0x100){227 pa = va + 0x20;228 addr[va >> 20] = pa 2;229 }230 }231 232 void enable_mmu(void)233 234 {235 unsigned long addr = 0x70;236 init_ttb(addr);237 //step:初始化页表238 239 unsigned long mmu = 1 (1 << 1) (1 << 8);240 //将MMU的第0,1,8方位1241 __asm__ __volatile__(242 "mov r0, #3\n"243 "MCR p15, 0, r0, c3, c0, 0\n"//manager244 "MCR p15, 0, %0, c2, c0, 0\n"//addr 245 "MCR p15, 0, %1, c1, c0, 0\n"// enable mmu246 :247 : "r" (addr), "r" (mmu)248 : "r0"249 );250 printf("MMU is enable!\n");251 }252 253 254
需求留意的是：在do_irq()函数中有一个清中止的操作，不然，将会告知中止操控器处理好了中止，避免一向触发外部中止：
87 void do_irq()
88 {
89 printf("key 1 down\n");
90 static int flag=1;
91 if(flag)
92 {
93 printf("wtc_on\n");
94 led_on();
95 pwm_on();
96 flag=0;
97 }
98 else if(flag == 0)
99 {
100 printf("wtc_off\n");
101 led_off();
102 pwm_off();
103 flag=1;
104 }
105
EXT_INT43PEND = (1 << 2);//清中止
106 }
当程序运转成功了之后，按下按键，LED和蜂鸣器就会作业，再按下按键，LED和蜂鸣器就会中止！
接下来，将曾经的中止问题归纳起来：写了一个用外部中止来操控LED灯业绩的比如
流程图是：
主要是do_rirq()函数：代码如下：
87 void do_irq()88 {89 printf("key 1 down\n");90 static int flag=1;91 if(flag)92 {93 printf("wtc_on\n");94 led_on();95 pwm_on();96 flag=0;97 }98 else if(flag == 0)99 {100 printf("wtc_off\n");101 led_off();102 pwm_off();103 flag=1;104 }105 EXT_INT43PEND = (1 << 2);//清中止106 }
接下来是整个程序的代码：
1 #include"regs.h"2 3 int (*printf)(char *, ...) = 0xc3e114d8;4 int(*delay)(int)=0xc3e25f90;5 6 void init_ttb(unsigned long *addr);7 void enable_mmu(void);8 unsigned long data_abort_init();9 void memcopy(unsigned long* dest,unsigned long* source,int len);10 void do_irq();11 void wtc_on();12 void wtc_off();13 void pwm_on(void);14 void pwm_off(void);15 void led_on(void);16 void led_on(void);17 18 19 20 int main()21 {22 *(unsigned long *)0x66 = do_irq;23 24 //产生反常时会进入反常形式跳转到0 4地址处理反常事情 25 unsigned long source_addr=data_abort_init();26 //反常事情处理函数27 printf("swi_souce addr is %x\n",source_addr);28 //将反常处理地址的值放到0x6429 memcopy(0x60,source_addr,0x1);30 31 enable_mmu();32 //内存映射将0x04映射到0x6004 33 34 //step 1: cpu cpsr35 __asm__ __volatile__(36 "mrs r0, cpsr\n"37 "bic r0, r0, #0x80\n"//设置CPSR的I位，将IRQ位翻开38 "msr cpsr, r0\n"39 ::: "r0"40 );41 42 //setp1:GIC43 ICCICR_CPU0 = 1;44 ICCPMR_CPU0 = 0xff;45 46 //6447 ICDDCR = 1;48 ICDIPR16_CPU0 = (0x0 << 0);//ICD第16个寄存器，第0位49 ICDIPTR16_CPU0 = (0x1 << 0);//优先级，最高50 ICDISER2_CPU0 = (1 << 0);//总共五个，第2个使能中止51 52 //7553 ICDIPR18_CPU0 = (0x0 << 24);54 //ICDIPTR0_CPU0 = 1;55 ICDIPTR18_CPU0 = (0x1 << 24);56 //ICDISER0_CPU0 = (1 << 0);57 ICDISER2_CPU0 = (1 << 11);58 59 //step 3: set gpio60 GPX3CON = (0xf << 8);//是GPXCON为外部中止功用61 62 //step 4: extern63 EXT_INT43CON = (2 << 8);//设置上升沿触发64 EXT_INT43MASK = 0;//使能中止65 66 /////////////////////////狗67 68 //step 5: sourcevoid pwm_on(void)69 70 71 72 printf("welcome back! \n");73 }74 75 void pwm_on(void)76 {77 GPD0CON &= ~0xffff;78 GPD0CON = 0x1;//装备寄存器为279 GPD0DAT = 0x1;//date=0xf80 }81 82 void pwm_off(void)83 {84 GPD0CON &= ~0xffff;85 GPD0CON = 0x0;86 // GPD0DAT &=0x0 ;//date=0xf87 88 }89 void led_off(void)90 {91 GPM4CON &= ~0xffff;//清零92 GPM4CON = 0x0;//03位清零93 GPM4DAT = 0x0;//date=0xf封闭置一94 }95 void led_on(void)96 {97 GPM4CON &= ~0xffff;98 GPM4CON = 0x1;//装备寄存器3-0--3-3全为1，全为输出形式99 GPM4DAT &= ~0xf;//翻开置0-4位为0100 }101 102 void wtc_on()103 {104 //step 3: interrupt source watchdog105 WTCON = 0 (1 << 2) (3 << 3) (1 << 5) (20 << 8);106 WTCNT = 0x8;107 WTDAT = 0x2;108 }109 110 void wtc_off(){112 WTCON = 0;113 }114 115 void do_irq()116 {117 // pwm_on();118 // led_on();119 // delay(6);120 // pwm_off();121 // led_off();122 123 unsigned long data = ICCIAR_CPU0;124 unsigned long irq_id = data & 0x3ff;125 unsigned long cpu_id = (data >> 10) & 0x7;126 ICCEOIR_CPU0 = irq_id (cpu_id << 10);127 printf("irq is %d, cpu is %d\n", irq_id, cpu_id);128 if(irq_id==64)//假如按键中止129 {130 if(EXT_INT43PEND & (1 << 2))131 {132 EXT_INT43PEND = (1 << 2);//清中止133 printf("key 1 down\n");134 static int flag=1;135 if(flag)136 {137 printf("wtc_on\n");138 wtc_on();139 flag=0;140 }141 else if(flag == 0)142 {143 printf("wtc_off\n");144 wtc_off();145 led_off();146 pwm_off();147 flag=1;148 }149 }150 }151 if(irq_id==75)//假如DOG中止152 {153 printf("dog dog dog \n");154 static int flag=1;155 if(flag)156 {157 led_on();158 pwm_on();159 flag=0;160 }161 else162 {163 led_off();164 pwm_off();165 flag=1;166 }167 WTCLRINT = 100;//清狗中止168 }169 170 }171 172 void memcopy(unsigned long* dest, unsigned long* source,int len)173 {174 int i=0;;175 for(i=0;i> 20] = pa 2;280 //2的意图是将0-2方位为10此刻将是小页形式4K281 }282 283 //00-10 ==== 6070284 for(va=0x00; va<=0x10; va+=0x100){285 pa = va+0x60;286 addr[va >> 20] = pa 2;287 }288 289 //10-14 ==== 1014290 for(va=0x10; va<=0x14; va+=0x100){291 pa = va;292 addr[va >> 20] = pa 2;293 }294 295 //30-40 ==== 5060296 for(va=0x30; va<0x40; va+=0x100){297 pa = va + 0x20;298 addr[va >> 20] = pa 2;299 }300 }301 302 void enable_mmu(void)303 304 {305 unsigned long addr = 0x70;306 init_ttb(addr);307 //step:初始化页表308 309 unsigned long mmu = 1 (1 << 1) (1 << 8);310 //将MMU的第0,1,8方位1311 __asm__ __volatile__(312 "mov r0, #3\n"313 "MCR p15, 0, r0, c3, c0, 0\n"//manager314 "MCR p15, 0, %0, c2, c0, 0\n"//addr 315 "MCR p15, 0, %1, c1, c0, 0\n"// enable mmu316 :317 : "r" (addr), "r" (mmu)318 : "r0"319 );320 printf("MMU is enable!\n");321 }322
运转成功：
发现当按下按键是触发外部中止，LED和蜂鸣器作业，当再次按下按键的时分，中止作业！看门狗在这儿的效果便是
不断的使LED和蜂鸣器业绩和鸣叫。
到这儿，ARM体系结构到一段落
