STM32 电子琴：GPIO、PWM 与中断的实战笔记

GPIO_PinRemapConfig(GPIO_Remap_SWJ_JTAGDisable, ENABLE);

void PWM_Init_1(void) {
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

    // PA0 设为复用推挽输出
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    // 时基配置：向上计数，ARR=99，PSC=719，默认 1kHz
    TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
    TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInitStructure.TIM_Period = 100 - 1;       // ARR = 99
    TIM_TimeBaseInitStructure.TIM_Prescaler = 720 - 1;    // PSC = 719
    TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStructure);

    // PWM 模式 1：CNT < CCR 时输出高电平
    TIM_OCInitTypeDef TIM_OCInitStructure;
    TIM_OCStructInit(&TIM_OCInitStructure);
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 0;   // CCR = 0，初始静音
    TIM_OC1Init(TIM2, &TIM_OCInitStructure);

    TIM_Cmd(TIM2, ENABLE);
}

void PWM_SetFreq_1(uint16_t freq) {
    uint16_t psc = 720000 / freq - 1;
    TIM_PrescalerConfig(TIM2, psc, TIM_PSCReloadMode_Update);
}

void PWM_SetDuty_1(uint16_t duty) {
    TIM_SetCompare1(TIM2, duty);   // duty 范围 0~100
}

void Buzzer_ON(uint16_t freq, uint8_t tone, uint8_t channel) {
    if (channel == 1) {        // 旋律通道 → TIM2_CH1 → PA0
        PWM_SetFreq_1(freq);
        PWM_SetDuty_1(tone);
    } else if (channel == 2) { // 伴奏通道 → TIM3_CH2 → PA7
        PWM_SetFreq_2(freq);
        PWM_SetDuty_2(tone);
    }
}

void Buzzer_Timing(uint16_t freq, uint16_t timing,
                   uint8_t tone, uint8_t channel) {
    Buzzer_ON(freq, tone, channel);
    Delay_ms(timing);
    Buzzer_OFF(channel);
}

void Buzzer_Reset(uint8_t channel) {
    PWM_SetFreq_1(1);
    TIM_SetCounter(TIM2, 51);   // CNT 跳到接近 ARR
}

void EXTI3_IRQHandler(void) {
    if (EXTI_GetITStatus(EXTI_Line3) == SET) {
        if (GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_3) == 1) {
            // ===== 按下琴键 =====
            if (voice == 6) {
                Buzzer_Drum(5);         // 鼓组模式：琴键变打击垫
            } else {
                Buzzer_Reset(1);        // ① 平滑音头
                uint16_t freq = scale[4 + sft]      // ② 查音阶表
                              * transpose[tsp]       // ③ 移调系数
                              * pow(2, oct)          // ④ 八度倍率
                              * pow(1.06, sharp);    // ⑤ 升半音
                Buzzer_ON(freq, voiceDuties[voice - 1], 1);  // ⑥ 发声
            }
        } else {
            // ===== 松开琴键 =====
            Buzzer_OFF(1);              // 立即静音
        }
        EXTI_ClearITPendingBit(EXTI_Line3);
    }
}

// 降八度键 (PA10)
if (GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_10) == 1)
    oct = 0;    // 按住 → 低八度
else
    oct = 1;    // 松开 → 恢复正常

void AD_Init(uint16_t pins) {
    // GPIO 模拟输入
    // ADC1 独立模式，软件触发，单次转换，右对齐
    // 采样时间 55.5 个 ADC 时钟周期
    // ADC 时钟 = PCLK2 / 6 = 12MHz
}

uint16_t AD_GetValue(uint8_t ADC_Channel) {
    ADC_RegularChannelConfig(ADC1, ADC_Channel, 1, ADC_SampleTime_55Cycles5);
    ADC_SoftwareStartConvCmd(ADC1, ENABLE);            // 启动转换
    while (ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) == RESET); // 等待完成
    return ADC_GetConversionValue(ADC1);               // 返回 0~4095
}

void EXTI0_IRQHandler(void) {  // B 相下降沿
    if (EXTI_GetITStatus(EXTI_Line0) == SET) {
        if (GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_1) == 0)
            Encoder_Count = 1;    // B 降沿时 A=0 → 正转
        EXTI_ClearITPendingBit(EXTI_Line0);
    }
}

void EXTI1_IRQHandler(void) {  // A 相下降沿
    if (EXTI_GetITStatus(EXTI_Line1) == SET) {
        if (GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_0) == 0)
            Encoder_Count = -1;   // A 降沿时 B=0 → 反转
        EXTI_ClearITPendingBit(EXTI_Line1);
    }
}

int16_t Encoder_Var(int16_t var, int8_t step,
                    int16_t min, int16_t max,
                    int16_t setL, int16_t setH) {
    var += Encoder_Get() * step;   // 累加旋转量
    if (var > max) var = setH;     // 超上限 → 跳转到 setH
    else if (var < min) var = setL; // 超下限 → 跳转到 setL
    Encoder_Clear();
    return var;
}

uint8_t voiceDuties[5] = {50, 40, 30, 20, 10};

Buzzer_Timing(80, 30, 50, 2);   // 80Hz 持续 30ms → 低音鼓
Buzzer_Timing(3000, 30, 10, 2); // 3000Hz 持续 30ms → 踩镲闭合

for (int i = 500; i > 470; i--) {
    Buzzer_ON(i, 50, 2);
    Delay_ms(1);
}

for (int i = 0; i < 15; i++) {
    Buzzer_ON(600, 50, 2);  Delay_ms(1);
    Buzzer_ON(1200, 30, 2); Delay_ms(1);
}

int main(void) {
    LED_Init_A(LED1 | LED2 | LED3);  // 3 颗 LED
    Key_Init_A(Key1 | Key4);         // 2 个按键 (PA)
    Key_Init_B(Key2 | Key3);         // 2 个按键 (PB)
    Buzzer_Init();                   // 双通道 PWM
    OLED_Init();                     // I2C OLED（现成驱动）
    Encoder_Init();                  // EC11 编码器
    Keyboard_Init();                 // 7 琴键 EXTI 中断
    JoyStick_Init();                 // PS2 摇杆 ADC + SW

    while (1) { /* 主循环 */ }
}