4X4矩阵键盘扫描程序

4X4矩阵键盘扫描：

1. 4根行线的GIO均设为Output，根列线的GIO均设为Input；

2. 4根行线的GIO分别置为0111、1011、1101、1110，读逐一读取列线GIO的值，可确定是哪一个按键；

电路图如下：

注意：

1. 图中用作输入的GIO，一定要有一个上拉电阻。

2. 芯片中的每一个引脚是否用作了GPIO口来用，需配置芯片的寄存器，使引脚当作GPIO口来使用，才会有效。

测试代码如下：

#define KEY_GIO_ROW_137#define KEY_GIO_ROW_233#define KEY_GIO_ROW_332#define KEY_GIO_ROW_435#define KEY_GIO_COL_122#define KEY_GIO_COL_223#define KEY_GIO_COL_324#define KEY_GIO_COL_436int scanKey(){int keyValue = 0;int col1Value=0,col2Value=0,col3Value=0,col4Value=0,row1Value=0,row2Value=0,row3Value=0,row4Value=0;static int press1=0,press2=0,press3=0,press4=0;static int press5=0,press6=0,press7=0,press8=0;static int press9=0,press10=0,press11=0,press12=0;static int press13=0,press14=0,press15=0,press16=0;dm365SetGPIO(KEY_GIO_ROW_1, 0);dm365SetGPIO(KEY_GIO_ROW_2, 1);dm365SetGPIO(KEY_GIO_ROW_3, 1);dm365SetGPIO(KEY_GIO_ROW_4, 1);col1Value = dm365GetGPIO(KEY_GIO_COL_1);col2Value = dm365GetGPIO(KEY_GIO_COL_2);col3Value = dm365GetGPIO(KEY_GIO_COL_3);col4Value = dm365GetGPIO(KEY_GIO_COL_4);keyValue = col1Value | (col2Value << 1) | (col3Value << 2) | (col4Value << 3);//printf("=1==keyValue = %x\n",keyValue);switch(keyValue){case 0x0E:{if(!press1){press1 = 1;printf("KEY 1\n");}}break;case 0x0D:{if(!press2){press2 = 1;printf("KEY 2\n");}}break;case 0x0B:{if(!press3){press3 = 1;printf("KEY 3\n");}}break;case 0x07:{if(!press4){press4 = 1;printf("KEY 4\n");}}break;default:{press1 = 0;press2 = 0;press3 = 0;press4 = 0;}break;}dm365SetGPIO(KEY_GIO_ROW_1, 1);dm365SetGPIO(KEY_GIO_ROW_2, 0);dm365SetGPIO(KEY_GIO_ROW_3, 1);dm365SetGPIO(KEY_GIO_ROW_4, 1);col1Value = dm365GetGPIO(KEY_GIO_COL_1);col2Value = dm365GetGPIO(KEY_GIO_COL_2);col3Value = dm365GetGPIO(KEY_GIO_COL_3);col4Value = dm365GetGPIO(KEY_GIO_COL_4);keyValue = col1Value | (col2Value << 1) | (col3Value << 2) | (col4Value << 3);//printf("=2==keyValue = %x\n",keyValue);switch(keyValue){case 0x0E:{if(!press5){press5 = 1;printf("KEY 5\n");}}break;case 0x0D:{if(!press6){press6 = 1;printf("KEY 6\n");}}break;case 0x0B:{if(!press7){press7 = 1;printf("KEY 7\n");}}break;case 0x07:{if(!press8){press8 = 1;printf("KEY 8\n");}}break;default:{press5 = 0;press6 = 0;press7 = 0;press8 = 0;}break;}dm365SetGPIO(KEY_GIO_ROW_1, 1);dm365SetGPIO(KEY_GIO_ROW_2, 1);dm365SetGPIO(KEY_GIO_ROW_3, 0);dm365SetGPIO(KEY_GIO_ROW_4, 1);col1Value = dm365GetGPIO(KEY_GIO_COL_1);col2Value = dm365GetGPIO(KEY_GIO_COL_2);col3Value = dm365GetGPIO(KEY_GIO_COL_3);col4Value = dm365GetGPIO(KEY_GIO_COL_4);keyValue = col1Value | (col2Value << 1) | (col3Value << 2) | (col4Value << 3);//printf("=3==keyValue = %x\n",keyValue);switch(keyValue){case 0x0E:{if(!press9){press9 = 1;printf("KEY 9\n");}}break;case 0x0D:{if(!press10){press10 = 1;printf("KEY 10\n");}}break;case 0x0B:{if(!press11){press11 = 1;printf("KEY 11\n");}}break;case 0x07:{if(!press12){press12 = 1;printf("KEY 12\n");}}break;default:{press9 = 0;press10 = 0;press11 = 0;press12 = 0;}break;}dm365SetGPIO(KEY_GIO_ROW_1, 1);dm365SetGPIO(KEY_GIO_ROW_2, 1);dm365SetGPIO(KEY_GIO_ROW_3, 1);dm365SetGPIO(KEY_GIO_ROW_4, 0);col1Value = dm365GetGPIO(KEY_GIO_COL_1);col2Value = dm365GetGPIO(KEY_GIO_COL_2);col3Value = dm365GetGPIO(KEY_GIO_COL_3);col4Value = dm365GetGPIO(KEY_GIO_COL_4);keyValue = col1Value | (col2Value << 1) | (col3Value << 2) | (col4Value << 3);//printf("=4==keyValue = %x\n",keyValue);switch(keyValue){case 0x0E:{if(!press13){press13 = 1;printf("KEY 13\n");}}break;case 0x0D:{if(!press14){press14 = 1;printf("KEY 14\n");}}break;case 0x0B:{if(!press15){press15 = 1;printf("KEY 15\n");}}break;case 0x07:{if(!press16){press16 = 1;printf("KEY 16\n");}}break;default:{press13 = 0;press14 = 0;press15 = 0;press16 = 0;}break;}return keyValue;}void *KeyMngThread(){int resetValue = 1;int resetCout = 0;int alarmInValue = 1;int alarmInCout = 0;while(1){resetValue = dm365GetGPIO(GIO_RESET);if(0 == resetValue){resetCout++;}else if(1 == resetValue){resetCout = 0;}if(resetCout == 30){resetCout = 0;system("rm -f /mnt/nand/sysenv.cfg");system("/bin/sync");//System("reboot");system("/tmp/shutdown -r now \n");}alarmInValue = dm365GetGPIO(GIO_ALARM_IN);if(0 == alarmInValue){dm365SetGPIO(GIO_LED,0);//control led off .}else if(1 == alarmInValue){dm365SetGPIO(GIO_LED,1);//control led on .}scanKey();usleep(100000);}}

代码中dm365SetGPIO( )里将GPIO默认设置为Output，

dm365GetGPIO( )中将GPIO默认设置为Input,

通过字符设备驱动实现应用层操作底层GPIO。