嵌入式系统下的键盘驱动程序。可识别三种类型的键盘动作：按下，抬起，一直按住。加入了去抖动的处理。文档附有，详细的原理说明，和简要的设计思想。该键盘驱动可适用于arm和dsp.-Embedded system under the keyboard driver. Identifies three types of keyboard actions: pressing, lifting, has been holding down the. Added to deal with jitter. Document with a detailed descr iption of the principle, and briefly the design idea. The keyboard-driven applied to arm and dsp.