55 lines
1.4 KiB
C
55 lines
1.4 KiB
C
/* KeyScan.c - 按键扫描模块 */
|
||
#include "KeyScan.h"
|
||
|
||
// 按键状态机结构体
|
||
typedef struct
|
||
{
|
||
uint8_t prev_state; // 前次状态
|
||
uint8_t edge_trigger; // 边沿触发标志
|
||
uint8_t scan_counter; // 扫描计数器
|
||
} KeyStateMachine;
|
||
|
||
static KeyStateMachine key_state = { 0xFF, 0x00, 0 };
|
||
|
||
/*******************************************
|
||
* 初始化函数
|
||
*******************************************/
|
||
void
|
||
Key_Init (void)
|
||
{
|
||
// 配置P2.4-P2.1为准双向口
|
||
P2M0 &= 0xE1;
|
||
P2M1 &= 0xE1;
|
||
|
||
// 初始化按键状态
|
||
key_state.prev_state = (KEY1 * 0x08) | (KEY2 * 0x04) | (KEY3 * 0x02) | KEY4;
|
||
}
|
||
|
||
/*******************************************
|
||
* 按键扫描函数
|
||
* 需在主循环中周期性调用
|
||
*******************************************/
|
||
void
|
||
Key_Scan (void)
|
||
{
|
||
const uint8_t current = (KEY1 * 0x08) | (KEY2 * 0x04) | (KEY3 * 0x02) | KEY4;
|
||
|
||
// 边沿检测
|
||
const uint8_t falling_edge
|
||
= (key_state.prev_state ^ current) & key_state.prev_state;
|
||
key_state.edge_trigger |= falling_edge; // 累积触发事件
|
||
|
||
key_state.prev_state = current; // 更新历史状态
|
||
}
|
||
|
||
/*******************************************
|
||
* 按键事件获取接口（供外部模块调用）
|
||
* 返回：4位掩码，对应KEY4-KEY1的触发状态
|
||
*******************************************/
|
||
uint8_t
|
||
Get_KeyEvents (void)
|
||
{
|
||
const uint8_t events = key_state.edge_trigger;
|
||
key_state.edge_trigger = 0; // 读取后清除标志
|
||
return events;
|
||
} |