嵌入式中断实验程序，按一次EXINT2,使LED1灭，再按一次EXINT2,又使LED1亮；

按一次EXINT3,使LED2灭，再按一次EXINT3,又使LED2亮。-Embedded interrupt experimental procedure, according to a EXINT2, so that LED1 off, and then a EXINT2, and the LED1 light　by a EXINT3, the LED2 off, and then a EXINT3, and the LED2 light.