2，嵌入式Linux之GPIO   1，点灯       1）看懂你所用的开发板的原理图 产看led和GPIO管脚是怎么接线的如图：
2) 通过s3c2440芯片控制寄存器配置GPF4 GPF5 GPF6为输入引脚 来点亮 上图的led灯             查看s3c2440芯片手册：


3) 配置GPIO 使得GPF4 GPF5 GPF6 为输出引脚并输出低电平                    用c语言先点亮GPF4 程序如下： #define GPFCON (*(volatile unsigned long *) 0x56000050) #define GPFDAT (*(volatile unsigned long *) 0x56000054) Int main (){ GPFCON = 0x100; Gpfdat = 0x0; Return 0; } //点亮 gpf4引脚的所在的那盏灯。
循环点灯 GPF 4 5 6:
#define gpfcon (*(volatile unsigned long *) 0x56000050) #define gpfdat (*(volatile unsigned long *) 0x56000054) #define gpf4_out (1<<(4*2)) #define gpf5_out (1<<(5*2)) #define gpf6_out (1<<(6*2)) Void wait(volatile unsigned dly){ For(;dly>0;dly--); } Int main(void){ unsigned long I=0; Gpfcon = gpf4_out|gpf5_out|gpf6_out; While(1){ Wait(3000); Gpfdat = (~(i<<4)); If(++i==8){ I=0; } } Return 0; }
4),按键点灯原理图：

         ①配置按键为输入引脚 led为输出引脚     ②读按键的值  根据值设置led的引脚值 #define GPFCON (*(volatile unsigned long *)0x56000050) #define GPFDAT (*(volatile unsigned long *)0x56000054) #define GPGCON (*(volatile unsigned long *)0x56000060) #define GPGDAT (*(volatile unsigned long *)0x56000064) /* * LED1,LED2,LED4对应GPF4、GPF5、GPF6 */ #define GPF4_out (1<<(4*2)) // 01 00 00 00 00 bit[9:8] 01 #define GPF5_out (1<<(5*2)) // 01 00 00 00 00 00 bit[11:10] 01 #define GPF6_out (1<<(6*2)) // 01 00 00 00 00 00 00 bit[13:12] 01 #define GPF4_msk (3<<(4*2)) // 11 00 00 00 00 bit[9:8] 11 #define GPF5_msk (3<<(5*2)) // 11 00 00 00 00 00 bit[11:10] 11 #define GPF6_msk (3<<(6*2)) // 11 00 00 00 00 00 00 bit[13:12] 11 /* * S2,S3,S4对应GPF0、GPF2、GPG3 */ #define GPF0_in (0<<(0*2)) #define GPF2_in (0<<(2*2)) #define GPG3_in (0<<(3*2)) #define GPF0_msk (3<<(0*2)) #define GPF2_msk (3<<(2*2)) #define GPG3_msk (3<<(3*2)) int main() { unsigned long dwDat; // LED1,LED2,LED4对应的3根引脚设为输出 /* GPF4_msk 11 00 00 00 00 GPF5_msk 11 00 00 00 00 00 GPF6_msk 11 00 00 00 00 00 00 GPF4_msk | GPF5_msk | GPF6_msk = 11 11 11 00 00 00 00 ~(GPF4_msk | GPF5_msk | GPF6_msk) = 00 00 00 11 11 11 11 */ GPFCON &= ~(GPF4_msk | GPF5_msk | GPF6_msk); /* GPF4_out | GPF5_out | GPF6_out = 01 01 01 00 00 00 00 */ GPFCON |= GPF4_out | GPF5_out | GPF6_out; // S2,S3对应的2根引脚设为输入 GPFCON &= ~(GPF0_msk | GPF2_msk); GPFCON |= GPF0_in | GPF2_in; // S4对应的引脚设为输入 GPGCON &= ~GPG3_msk; GPGCON |= GPG3_in; while(1){ //若Kn为0(表示按下)，则令LEDn为0(表示点亮) dwDat = GPFDAT; // 读取GPF管脚电平状态 if (dwDat & (1<<0)) // S2没有按下 GPFDAT |= (1<<4); // LED1熄灭 else GPFDAT &= ~(1<<4); // LED1点亮 if (dwDat & (1<<2)) // S3没有按下 GPFDAT |= (1<<5); // LED2熄灭 else GPFDAT &= ~(1<<5); // LED2点亮 dwDat = GPGDAT; // 读取GPG管脚电平状态 if (dwDat & (1<<3)) // S4没有按下 GPFDAT |= (1<<6); // LED3熄灭 else GPFDAT &= ~(1<<6); // LED3点亮 } return 0; }