/**
 * 实验一：1秒定时闪烁 - Wokwi适配版（带串口调试）
 * 芯片：STM32C031C6 (Wokwi平台)
 * 连接：LED正极 -> PA5, LED负极 -> GND
 *      串口：PA2(TX), PA3(RX) - 使用USART2
 */

// 寄存器地址定义
#define RCC_BASE         0x40021000UL
#define RCC_IOPENR       (*(volatile unsigned int*)(RCC_BASE + 0x34))
#define RCC_APBENR1      (*(volatile unsigned int*)(RCC_BASE + 0x3C))
#define RCC_APBENR2      (*(volatile unsigned int*)(RCC_BASE + 0x40))

#define GPIOA_BASE       0x50000000UL
#define GPIOA_MODER      (*(volatile unsigned int*)(GPIOA_BASE + 0x00))
#define GPIOA_AFRL       (*(volatile unsigned int*)(GPIOA_BASE + 0x20))
#define GPIOA_ODR        (*(volatile unsigned int*)(GPIOA_BASE + 0x14))

#define USART2_BASE      0x40004400UL
#define USART2_CR1       (*(volatile unsigned int*)(USART2_BASE + 0x00))
#define USART2_CR2       (*(volatile unsigned int*)(USART2_BASE + 0x04))
#define USART2_BRR       (*(volatile unsigned int*)(USART2_BASE + 0x0C))
#define USART2_ISR       (*(volatile unsigned int*)(USART2_BASE + 0x1C))
#define USART2_TDR       (*(volatile unsigned int*)(USART2_BASE + 0x28))

#define TIM3_BASE        0x40000400UL
#define TIM3_CR1         (*(volatile unsigned int*)(TIM3_BASE + 0x00))
#define TIM3_DIER        (*(volatile unsigned int*)(TIM3_BASE + 0x0C))
#define TIM3_SR          (*(volatile unsigned int*)(TIM3_BASE + 0x10))
#define TIM3_CNT         (*(volatile unsigned int*)(TIM3_BASE + 0x24))
#define TIM3_PSC         (*(volatile unsigned int*)(TIM3_BASE + 0x28))
#define TIM3_ARR         (*(volatile unsigned int*)(TIM3_BASE + 0x2C))

// 位定义 - 请补充完整
#define RCC_IOPENR_GPIOAEN   (1 << 0)    // GPIOA时钟使能位
#define RCC_APBENR1_TIM3EN   (1 << 1)    // TIM3时钟使能位（填空）
#define RCC_APBENR2_USART2EN (1 << 0)    // USART2时钟使能位（填空）
#define TIM_CR1_CEN          (1 << 0)     // 定时器使能位
#define TIM_DIER_UIE         (1 << 0)      // 更新中断使能位
#define TIM_SR_UIF           (1 << 0)      // 更新中断标志位


// USART位定义
#define USART_CR1_UE         (1 << 0)
#define USART_CR1_TE         (1 << 3)
#define USART_CR1_RE         (1 << 2)
#define USART_ISR_TXE        (1 << 7)
#define USART_ISR_TC         (1 << 6)

// LED状态变量
volatile int led_state = 0;
volatile unsigned int tick_count = 0;
volatile unsigned int blink_counter = 0;

// 简单的延时函数
void simpleDelay(volatile unsigned int time) {
    for (volatile unsigned int i = 0; i < time; i++) {
        for (volatile unsigned int j = 0; j < 100; j++);
    }
}

// 串口初始化函数
void USART2_Init(void) {
    // 1. 使能USART2和GPIOA时钟
    RCC_APBENR2 |= RCC_APBENR2_USART2EN;
    RCC_IOPENR |= RCC_IOPENR_GPIOAEN;
    simpleDelay(100);
    
    // 2. 配置PA2(TX)为复用功能
    GPIOA_MODER &= ~(3 << (2 * 2));  // 清除PA2模式
    GPIOA_MODER |= (2 << (2 * 2));   // 复用功能模式
    
    // 3. 配置PA3(RX)为复用功能（可选）
    GPIOA_MODER &= ~(3 << (3 * 2));
    GPIOA_MODER |= (2 << (3 * 2));
    
    // 4. 配置复用功能为USART2 (AF1)
    GPIOA_AFRL &= ~(0xF << (2 * 4));  // 清除PA2的AF
    GPIOA_AFRL |= (1 << (2 * 4));     // AF1 for PA2 (USART2_TX)
    GPIOA_AFRL &= ~(0xF << (3 * 4));  // 清除PA3的AF
    GPIOA_AFRL |= (1 << (3 * 4));     // AF1 for PA3 (USART2_RX)
    
    // 5. 配置USART2参数
    // 波特率计算：48MHz / 9600 = 5000
    USART2_BRR = 5000;  // 9600波特率 @ 48MHz
    
    // 6. 使能USART2，发送和接收
    USART2_CR1 |= USART_CR1_UE;   // 使能USART
    USART2_CR1 |= USART_CR1_TE;   // 使能发送
    USART2_CR1 |= USART_CR1_RE;   // 使能接收（可选）
    
    simpleDelay(100);
}

// 串口发送单个字符
void USART2_SendChar(char c) {
    // 等待发送缓冲区空
    while (!(USART2_ISR & USART_ISR_TXE));
    USART2_TDR = c;
}

// 串口发送字符串
void USART2_SendString(char* str) {
    while (*str) {
        USART2_SendChar(*str++);
    }
}

// 串口发送数字（十进制）
void USART2_SendNumber(unsigned int num) {
    char buffer[16];
    int i = 0;
    
    // 处理0的情况
    if (num == 0) {
        USART2_SendChar('0');
        return;
    }
    
    // 将数字转换为字符串（逆序）
    while (num > 0) {
        buffer[i++] = '0' + (num % 10);
        num /= 10;
    }
    
    // 逆序输出
    while (i > 0) {
        USART2_SendChar(buffer[--i]);
    }
}

// 串口发送带格式的消息
void USART2_Printf(const char* format, ...) {
    // 简化版，只支持基本字符串输出
    // 实际项目中可以使用vsprintf等函数
    USART2_SendString((char*)format);
}

// 发送调试信息
void sendDebugInfo(void) {
    USART2_SendString("\r\n[调试] LED状态: ");
    if (led_state) {
        USART2_SendString("亮");
    } else {
        USART2_SendString("灭");
    }
    
    USART2_SendString(" | 计数: ");
    USART2_SendNumber(blink_counter);
    USART2_SendString(" | 定时器值: ");
    USART2_SendNumber(TIM3_CNT);
    USART2_SendString("\r\n");
}

void setup() {
    // --- 1. 使能GPIOA时钟 ---
    RCC_IOPENR |= RCC_IOPENR_GPIOAEN;
    simpleDelay(100);
    
    // --- 2. 配置PA5为输出模式 ---
    GPIOA_MODER &= ~(3 << (5 * 2));  // 清除模式位
    GPIOA_MODER |= (1 << (5 * 2));   // 设置为输出模式
    
    // 初始状态：LED灭
    GPIOA_ODR &= ~(1 << 5);
    led_state = 0;
    
    // --- 3. 初始化串口调试 ---
    USART2_Init();
    USART2_SendString("\r\n====================================\r\n");
    USART2_SendString("STM32C031 LED闪烁程序 - 调试模式\r\n");
    USART2_SendString("系统时钟: 48MHz\r\n");
    USART2_SendString("定时器: TIM3, 1秒间隔\r\n");
    USART2_SendString("LED引脚: PA5\r\n");
    USART2_SendString("串口: 9600-8-N-1\r\n");
    USART2_SendString("====================================\r\n\n");
    
    // --- 4. 使能TIM3时钟 ---
    RCC_APBENR1 |= RCC_APBENR1_TIM3EN;
    simpleDelay(100);
    
    // --- 5. 配置定时器参数（1秒定时）---
    TIM3_PSC = 4800 - 1;     // 48MHz/4800 = 10kHz (0.1ms/计数)
    TIM3_ARR = 10000 - 1;     // 计数10000次 = 1秒
    TIM3_CNT = 0;             // 从0开始计数
    
    // --- 6. 清除中断标志并配置中断 ---
    TIM3_SR &= ~TIM_SR_UIF;    // 清除更新标志
    TIM3_DIER |= TIM_DIER_UIE; // 使能更新中断
    
    // --- 7. 启动定时器 ---
    TIM3_CR1 |= TIM_CR1_CEN;   // 使能计数器
    
    USART2_SendString("定时器配置完成\r\n");
    USART2_SendString("等待LED闪烁...\r\n\n");
    
    // --- 8. 配置完成 ---
}

void loop() {
    static unsigned int last_second = 0;
    static unsigned int debug_counter = 0;
    
    // 轮询方式检查定时器标志（不使用中断）
    if (TIM3_SR & TIM_SR_UIF) {
        // 清除中断标志
        TIM3_SR &= ~TIM_SR_UIF;
        
        // 翻转LED状态
        if (led_state) {
            GPIOA_ODR &= ~(1 << 5);  // LED灭
            led_state = 0;
            USART2_SendString("[事件] LED熄灭\r\n");
        } else {
            GPIOA_ODR |= (1 << 5);   // LED亮
            led_state = 1;
            USART2_SendString("[事件] LED点亮\r\n");
        }
        
        blink_counter++;
        
        // 每10秒发送一次详细状态
        if (blink_counter % 10 == 0) {
            USART2_SendString("\r\n--- 状态更新 ---\r\n");
            USART2_SendString("闪烁次数: ");
            USART2_SendNumber(blink_counter);
            USART2_SendString("\r\n系统运行时间: ");
            USART2_SendNumber(blink_counter);
            USART2_SendString(" 秒\r\n");
            USART2_SendString("----------------\r\n");
        }
    }
    
    // 每秒打印一个点表示程序正在运行（非阻塞）
    unsigned int current_time = TIM3_CNT;
    if (current_time > last_second + 5000) {  // 大约0.5秒
        last_second = current_time;
        debug_counter++;
        if (debug_counter % 2 == 0) {  // 每秒打印一次
            USART2_SendChar('.');  // 打印运行指示
        }
    }
}

// 注意：这个版本使用轮询方式而不是中断，这样在Wokwi中更可靠