3.27_433：添加UART2调试打印、IO监控、指令解析和继电器控制模块。

能够接收UART2指令控制继电器开关，或向UART2发送四路IO输入状态，并使用轮询方式检测IO状态进行及时反馈。

Core/Src/io_monitor.c

@@ -0,0 +1,158 @@
+/**
+  ******************************************************************************
+  * @file    io_monitor.c
+  * @brief   IO状态监控模块实现
+  * @author  Application Layer
+  * @version 1.1
+  ******************************************************************************
+  * @attention
+  * 本模块实现四路数字输入的状态监控
+  * 关键特性：
+  * 1. 10ms定时扫描，平衡响应速度和CPU占用
+  * 2. 软件去抖，连续3次相同状态才确认变化
+  * 3. 状态变化时自动上报ASCII格式消息
+  * 
+  * 修订历史：
+  * v1.1 - 修复审查报告中危-5：去抖计数器初始化优化
+  ******************************************************************************
+  */
+
+#include "io_monitor.h"
+#include "uart2_print.h"
+#include "main.h"
+#include <string.h>
+
+#define DEBUG_IO_MONITOR  1
+
+#if DEBUG_IO_MONITOR
+#define DEBUG_LOG(fmt, ...)  UART2_Print_Printf("[IO] " fmt "\r\n", ##__VA_ARGS__)
+#else
+#define DEBUG_LOG(fmt, ...)
+#endif
+
+typedef struct {
+    GPIO_TypeDef *port;
+    uint16_t pin;
+    uint8_t  current_state;
+    uint8_t  debounce_counter;
+    uint8_t  last_raw_state;
+    uint32_t change_count;
+} io_channel_t;
+
+static io_channel_t di_channels[IO_CHANNEL_COUNT] = {
+    {GPIOB, GPIO_PIN_4, 0, 0, 0, 0},
+    {GPIOB, GPIO_PIN_5, 0, 0, 0, 0},
+    {GPIOB, GPIO_PIN_6, 0, 0, 0, 0},
+    {GPIOB, GPIO_PIN_7, 0, 0, 0, 0}
+};
+
+static uint32_t last_scan_tick = 0;
+static bool report_enabled = true;
+
+static uint8_t calc_checksum(const char *data, uint8_t len)
+{
+    uint8_t cs = 0;
+    for (uint8_t i = 0; i < len; i++) {
+        cs ^= (uint8_t)data[i];
+    }
+    return cs;
+}
+
+static void send_di_event(uint8_t channel, uint8_t state)
+{
+    char msg[32];
+    uint8_t cs;
+    
+    int len = snprintf(msg, sizeof(msg), "$DI_EVENT,%d,%d*", channel + 1, state);
+    
+    cs = calc_checksum(msg + 1, len - 1);
+    
+    snprintf(msg + len, sizeof(msg) - len, "%02X\r\n", cs);
+    
+    UART2_Print_String(msg);
+    
+    DEBUG_LOG("CH%d -> %s", channel + 1, state ? "HIGH" : "LOW");
+}
+
+void IO_Monitor_Init(void)
+{
+    for (int i = 0; i < IO_CHANNEL_COUNT; i++) {
+        io_channel_t *ch = &di_channels[i];
+        
+        ch->current_state = HAL_GPIO_ReadPin(ch->port, ch->pin) ? 1 : 0;
+        ch->last_raw_state = ch->current_state;
+        ch->debounce_counter = 1;
+        ch->change_count = 0;
+    }
+    
+    last_scan_tick = 0;
+    report_enabled = true;
+    
+    DEBUG_LOG("Init OK, initial states: 0x%02X", IO_Monitor_GetAllStates());
+}
+
+void IO_Monitor_Task(void)
+{
+    uint32_t current_tick = HAL_GetTick();
+    
+    if (current_tick - last_scan_tick < IO_SCAN_PERIOD_MS) {
+        return;
+    }
+    last_scan_tick = current_tick;
+    
+    for (int i = 0; i < IO_CHANNEL_COUNT; i++) {
+        io_channel_t *ch = &di_channels[i];
+        
+        uint8_t raw_state = HAL_GPIO_ReadPin(ch->port, ch->pin) ? 1 : 0;
+        
+        if (raw_state != ch->last_raw_state) {
+            ch->debounce_counter = 0;
+            ch->last_raw_state = raw_state;
+        } else {
+            if (ch->debounce_counter < IO_DEBOUNCE_COUNT) {
+                ch->debounce_counter++;
+            } else if (ch->current_state != raw_state) {
+                ch->current_state = raw_state;
+                ch->change_count++;
+                
+                if (report_enabled) {
+                    send_di_event(i, raw_state);
+                }
+            }
+        }
+    }
+}
+
+uint8_t IO_Monitor_GetState(uint8_t channel)
+{
+    if (channel >= IO_CHANNEL_COUNT) {
+        return 0;
+    }
+    return di_channels[channel].current_state;
+}
+
+uint8_t IO_Monitor_GetAllStates(void)
+{
+    uint8_t states = 0;
+    
+    for (int i = 0; i < IO_CHANNEL_COUNT; i++) {
+        if (di_channels[i].current_state) {
+            states |= (1 << i);
+        }
+    }
+    return states;
+}
+
+void IO_Monitor_EnableReport(bool enable)
+{
+    report_enabled = enable;
+    DEBUG_LOG("Report %s", enable ? "enabled" : "disabled");
+}
+
+uint32_t IO_Monitor_GetChangeCount(uint8_t channel)
+{
+    if (channel >= IO_CHANNEL_COUNT) {
+        return 0;
+    }
+    return di_channels[channel].change_count;
+}