1 objs := head.o init.o interrupt.o main.o 2  3 int.bin: $(objs) 4     arm-linux-ld -Ttext 0x00000000 -o int_elf $^ 5     arm-linux-objcopy -O binary -S int_elf $@ 6     arm-linux-objdump -D -m arm int_elf > int.dis 7      8 %.o:%.c 9     arm-linux-gcc -Wall -O2 -c -o $@ $<10 11 %.o:%.S12     arm-linux-gcc -Wall -O2 -c -o $@ $<13 14 clean:15     rm -f int.bin int_elf int.dis *.o        16     

 1 @****************************************************************************** 2 @ File：head.S 3 @ 功能：初始化，设置中断模式、管理模式的栈，设置好中断处理函数 4 @******************************************************************************        5     6 .extern     main 7 .text  8 .global _start  9 _start:10 @******************************************************************************       11 @ 中断向量，本程序中，除Reset和HandleIRQ外，其它异常都没有使用12 @******************************************************************************       13     b   Reset14 15 @ 0x04: 未定义指令中止模式的向量地址16 HandleUndef:17     b   HandleUndef 18  19 @ 0x08: 管理模式的向量地址，通过SWI指令进入此模式20 HandleSWI:21     b   HandleSWI22 23 @ 0x0c: 指令预取终止导致的异常的向量地址24 HandlePrefetchAbort:25     b   HandlePrefetchAbort26 27 @ 0x10: 数据访问终止导致的异常的向量地址28 HandleDataAbort:29     b   HandleDataAbort30 31 @ 0x14: 保留32 HandleNotUsed:33     b   HandleNotUsed34 35 @ 0x18: 中断模式的向量地址36     b   HandleIRQ37 38 @ 0x1c: 快中断模式的向量地址39 HandleFIQ:40     b   HandleFIQ41 42 Reset:                  43     ldr sp, =4096           @ 设置栈指针，以下都是C函数，调用前需要设好栈44     bl  disable_watch_dog   @ 关闭WATCHDOG，否则CPU会不断重启45     46     msr cpsr_c, #0xd2       @ 进入中断模式47     ldr sp, =3072           @ 设置中断模式栈指针48 49     msr cpsr_c, #0xd3       @ 进入管理模式50     ldr sp, =4096           @ 设置管理模式栈指针，51                             @ 其实复位之后，CPU就处于管理模式，52                             @ 前面的“ldr sp, =4096”完成同样的功能，此句可省略53 54     bl  init_led            @ 初始化LED的GPIO管脚55     bl  init_irq            @ 调用中断初始化函数，在init.c中56     msr cpsr_c, #0x5f       @ 设置I-bit=0，开IRQ中断57     58     ldr lr, =halt_loop      @ 设置返回地址59     ldr pc, =main           @ 调用main函数60 halt_loop:61     b   halt_loop62 63 HandleIRQ:64     sub lr, lr, #4                  @ 计算返回地址65     stmdb   sp!,    { r0-r12,lr }   @ 保存使用到的寄存器66                                     @ 注意，此时的sp是中断模式的sp67                                     @ 初始值是上面设置的307268     69     ldr lr, =int_return             @ 设置调用ISR即EINT_Handle函数后的返回地址  70     ldr pc, =EINT_Handle            @ 调用中断服务函数，在interrupt.c中71 int_return:72     ldmia   sp!,    { r0-r12,pc }^  @ 中断返回, ^表示将spsr的值复制到cpsr73     

 1 /* 2  * init.c: 进行一些初始化 3  */  4  5 #include "s3c24xx.h" 6  7 /* 8  * LED1,LED2,LED4对应GPF4、GPF5、GPF6 9  */10 #define    GPF4_out    (1<<(4*2))11 #define    GPF5_out    (1<<(5*2))12 #define    GPF6_out    (1<<(6*2))13 14 #define    GPF4_msk    (3<<(4*2))15 #define    GPF5_msk    (3<<(5*2))16 #define    GPF6_msk    (3<<(6*2))17 18 /*19  * S2,S3,S4对应GPF0、GPF2、GPG320  */21 #define GPF0_eint     (0x2<<(0*2))22 #define GPF2_eint     (0x2<<(2*2))23 #define GPG3_eint     (0x2<<(3*2))24 25 #define GPF0_msk    (3<<(0*2))26 #define GPF2_msk    (3<<(2*2))27 #define GPG3_msk    (3<<(3*2))28 29 /*30  * 关闭WATCHDOG，否则CPU会不断重启31  */32 void disable_watch_dog(void)33 {34     WTCON = 0;  // 关闭WATCHDOG很简单，往这个寄存器写0即可35 }36 37 void init_led(void)38 {39     // LED1,LED2,LED4对应的3根引脚设为输出40     GPFCON &= ~(GPF4_msk | GPF5_msk | GPF6_msk);41     GPFCON |= GPF4_out | GPF5_out | GPF6_out;42 }43 44 /*45  * 初始化GPIO引脚为外部中断46  * GPIO引脚用作外部中断时，默认为低电平触发、IRQ方式(不用设置INTMOD)47  */ 48 void init_irq( )49 {50     // S2,S3对应的2根引脚设为中断引脚 EINT0,ENT251     GPFCON &= ~(GPF0_msk | GPF2_msk);52     GPFCON |= GPF0_eint | GPF2_eint;53 54     // S4对应的引脚设为中断引脚EINT1155     GPGCON &= ~GPG3_msk;56     GPGCON |= GPG3_eint;57     58     // 对于EINT11，需要在EINTMASK寄存器中使能它59     EINTMASK &= ~(1<<11);60         61     /*62      * 设定优先级：63      * ARB_SEL0 = 00b, ARB_MODE0 = 0: REQ1 > REQ3，即EINT0 > EINT264      * 仲裁器1、6无需设置65      * 最终：66      * EINT0 > EINT2 > EINT11即K2 > K3 > K467      */68     PRIORITY = (PRIORITY & ((~0x01) | (0x3<<7))) | (0x0 << 7) ;69 70     // EINT0、EINT2、EINT8_23使能71     INTMSK   &= (~(1<<0)) & (~(1<<2)) & (~(1<<5));72 }

 1 #include "s3c24xx.h" 2  3 void EINT_Handle() 4 { 5     unsigned long oft = INTOFFSET; 6     unsigned long val; 7      8     switch( oft ) 9     {10         // S2被按下11         case 0: 12         {   13             GPFDAT |= (0x7<<4);   // 所有LED熄灭14             GPFDAT &= ~(1<<4);      // LED1点亮15             break;16         }17         18         // S3被按下19         case 2:20         {   21             GPFDAT |= (0x7<<4);   // 所有LED熄灭22             GPFDAT &= ~(1<<5);      // LED2点亮23             break;24         }25 26         // K4被按下27         case 5:28         {   29             GPFDAT |= (0x7<<4);   // 所有LED熄灭30             GPFDAT &= ~(1<<6);      // LED4点亮                31             break;32         }33 34         default:35             break;36     }37 38     //清中断39     if( oft == 5 ) 40         EINTPEND = (1<<11);   // EINT8_23合用IRQ541     SRCPND = 1<<oft;42     INTPND = 1<<oft;43 }

 1 /* WOTCH DOG register */ 2 #define     WTCON           (*(volatile unsigned long *)0x53000000) 3  4 /* SDRAM regisers */ 5 #define     MEM_CTL_BASE    0x48000000 6 #define     SDRAM_BASE      0x30000000 7  8 /* NAND Flash registers */ 9 #define NFCONF              (*(volatile unsigned int  *)0x4e000000)10 #define NFCMD               (*(volatile unsigned char *)0x4e000004)11 #define NFADDR              (*(volatile unsigned char *)0x4e000008)12 #define NFDATA              (*(volatile unsigned char *)0x4e00000c)13 #define NFSTAT              (*(volatile unsigned char *)0x4e000010)14 15 /*GPIO registers*/16 #define GPBCON              (*(volatile unsigned long *)0x56000010)17 #define GPBDAT              (*(volatile unsigned long *)0x56000014)18 19 #define GPFCON              (*(volatile unsigned long *)0x56000050)20 #define GPFDAT              (*(volatile unsigned long *)0x56000054)21 #define GPFUP               (*(volatile unsigned long *)0x56000058)22 23 #define GPGCON              (*(volatile unsigned long *)0x56000060)24 #define GPGDAT              (*(volatile unsigned long *)0x56000064)25 #define GPGUP               (*(volatile unsigned long *)0x56000068)26 27 #define GPHCON              (*(volatile unsigned long *)0x56000070)28 #define GPHDAT              (*(volatile unsigned long *)0x56000074)29 #define GPHUP               (*(volatile unsigned long *)0x56000078)30 31 32 33 /*UART registers*/34 #define ULCON0              (*(volatile unsigned long *)0x50000000)35 #define UCON0               (*(volatile unsigned long *)0x50000004)36 #define UFCON0              (*(volatile unsigned long *)0x50000008)37 #define UMCON0              (*(volatile unsigned long *)0x5000000c)38 #define UTRSTAT0            (*(volatile unsigned long *)0x50000010)39 #define UTXH0               (*(volatile unsigned char *)0x50000020)40 #define URXH0               (*(volatile unsigned char *)0x50000024)41 #define UBRDIV0             (*(volatile unsigned long *)0x50000028)42 43 44 /*interrupt registes*/45 #define SRCPND              (*(volatile unsigned long *)0x4A000000)46 #define INTMOD              (*(volatile unsigned long *)0x4A000004)47 #define INTMSK              (*(volatile unsigned long *)0x4A000008)48 #define PRIORITY            (*(volatile unsigned long *)0x4A00000c)49 #define INTPND              (*(volatile unsigned long *)0x4A000010)50 #define INTOFFSET           (*(volatile unsigned long *)0x4A000014)51 #define SUBSRCPND           (*(volatile unsigned long *)0x4A000018)52 #define INTSUBMSK           (*(volatile unsigned long *)0x4A00001c)53 54 /*external interrupt registers*/55 #define EINTMASK            (*(volatile unsigned long *)0x560000a4)56 #define EINTPEND            (*(volatile unsigned long *)0x560000a8)