按键驱动

今天整理一下按键驱动开发步骤, 采用Zilog CPU

1.用宏定义好input output GPIO口线的mask, 首先对口线进行初始化.初始化步骤如下:

//step1: Configure the GPIO0s as the universal IO Pin

//step2: Configure the Input Pin

//step3: Configure the Output Pin, and OutPut low

//step4: Configure input pins' interrupt

//Step4.1: Clear the input GPIO0s Pin's interrupt

//Step4.2: Clear Interrupt Pending Flop

//Step4.3: Configure as A channel Interrupt

//Step4.4: Configure GPIO0s as Level trigger Interrupt

//Step4.5: Configure GPIO0s as Falling Interrupt

//Step5: Init global variables

//Step6: Set GPIO interrup handler and init timer event

//Step7: Enable Input pins' Interrupt

//Step8: Enable the GPIO0A Interrupt Control

PS:中断口都作为Input, output口线要配置电平.

2.初始化后, 编写Step6中的Interrupt handler.

//Step1: Disable Gpio interrupt

//Step2: init variable.

//Step3: Start timer event, every 20ms do a scan.

//Step4: clear interrupt pending.

3.很重要的一步:用20ms中断定时器事件进行键值扫描.