ADS1.2裸板调试mini2440按键控制LED（含源码）

$$$$$$$$$$  crt0.S    $$$$$$$$$$$$$$
 

;****************************************

file：crt0.S
; 功能：通过它转入C程序
;*******************************************      
            IMPORT Main
            AREA  KEY_LED, CODE, READONLY
            ENTRY
            CODE32
START       ldr     r0, =0x53000000     ; WATCHDOG寄存器地址
            mov     r1, #0x0                    
            str     r1, [r0]            ; 写入0，禁止WATCHDOG，否则CPU会不断重启
            ldr     sp, =1024*100     
            bl      Main                ; 调用C程序中的main函数
halt_loop
            b       halt_loop

            END

^^^^^^^^^^^^^^^  key_led.c  ^^^^^^^^^^^

#define GPBCON      (*(volatile unsigned long *)0x56000010)
#define GPBDAT      (*(volatile unsigned long *)0x56000014)

#define GPGCON      (*(volatile unsigned long *)0x56000060)
#define GPGDAT      (*(volatile unsigned long *)0x56000064)

/*
 * LED1-4对应GPB5、GPB6、GPB7、GPB8
 */
#define GPB5_out        (1<<(5*2))
#define GPB6_out        (1<<(6*2))
#define GPB7_out        (1<<(7*2))
#define GPB8_out        (1<<(8*2))

/*
 * K1-K4对应GPG6、GPG5、GPG3、GPG0
 */
#define GPG6_in    ~(3<<(6*2))
#define GPG5_in     ~(3<<(5*2))
#define GPG3_in     ~(3<<(3*2))
#define GPG0_in     ~(3<<(0*2))

int Main()
{
        unsigned long dwDat;
        // LED1-LED4对应的4根引脚设为输出
        GPBCON = GPB5_out | GPB6_out | GPB7_out | GPB8_out ;

        // K1-K4对应的2根引脚设为输入
        GPGCON = GPG6_in & GPG5_in & GPG3_in & GPG0_in;
  
        while(1){
            //若Kn为0(表示按下)，则令LEDn为0(表示点亮)
            dwDat = GPGDAT;             // 读取GPG管脚电平状态
       
            if (dwDat & (1<<0))        // K1没有按下
                GPBDAT |= (1<<5);       // LED1熄灭
            else   
                GPBDAT &= ~(1<<5);      // LED1点亮
               
            if (dwDat & (1<<3))         // K2没有按下
                GPBDAT |= (1<<6);       // LED2熄灭
            else   
                GPBDAT &= ~(1<<6);      // LED2点亮
                       
            if (dwDat & (1<<5))         // K3没有按下
                GPBDAT |= (1<<7);       // LED3熄灭
            else   
                GPBDAT &= ~(1<<7);      // LED3点亮
   
            if (dwDat & (1<<6))         // K4没有按下
                GPBDAT |= (1<<8);       // LED4熄灭
            else   
                GPBDAT &= ~(1<<8);      // LED4点亮
    }

    return 0;
}