DC 모터 제어 — H-Bridge·PWM Duty·Encoder Feedback

1
DIR=0, PWM=duty: IN1=PWM,   IN2=0     → forward, speed=duty
2
DIR=1, PWM=duty: IN1=0,     IN2=PWM   → reverse

1
PWM=50%:  정지 (양방향 동일 시간)
2
PWM=75%:  forward 25%
3
PWM=25%:  reverse 25%

1
// AIN1 = PA0 (PWM TIM2_CH1, AF1), AIN2 = PA1 (GPIO)
2
void motor_init(void) {
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    RCC->APB1ENR |= RCC_APB1ENR_TIM2EN;
4

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    gpio_init(GPIOA, 0, &(gpio_config_t){.mode=GPIO_MODE_AF, .af=1});
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    gpio_init(GPIOA, 1, &(gpio_config_t){.mode=GPIO_MODE_OUTPUT});
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8
    // 20 kHz PWM
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    TIM2->PSC = 0;
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    TIM2->ARR = 4200 - 1;          // 84 MHz / 4200 = 20 kHz
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    TIM2->CCMR1 = (6u << 4) | TIM_CCMR1_OC1PE;
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    TIM2->CCER  = TIM_CCER_CC1E;
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    TIM2->CCR1  = 0;
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    TIM2->CR1   = TIM_CR1_ARPE | TIM_CR1_CEN;
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    TIM2->EGR   = TIM_EGR_UG;
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}
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18
void motor_set(int16_t speed) {
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    // speed = -1000 ~ +1000
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    if (speed >= 0) {
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        GPIOA->BSRR = (1u << (1 + 16));   // AIN2 = 0
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        TIM2->CCR1 = (uint32_t)speed * (TIM2->ARR + 1) / 1000;
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    } else {
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        GPIOA->BSRR = (1u << 1);          // AIN2 = 1
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        // 음수 speed: AIN1 PWM의 *off 시간*이 forward duty
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        TIM2->CCR1 = (TIM2->ARR + 1) - ((uint32_t)(-speed) * (TIM2->ARR + 1) / 1000);
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    }
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}
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void motor_brake(void) {
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    GPIOA->BSRR = (1u << 1);              // AIN2 = 1
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    TIM2->CCR1 = TIM2->ARR + 1;           // AIN1 = always 1 → short
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}
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void motor_coast(void) {
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    GPIOA->BSRR = (1u << (1 + 16));       // AIN2 = 0
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    TIM2->CCR1 = 0;                        // AIN1 = 0 → high-Z
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}

1
// AIN1, AIN2 = GPIO direction, PWMA = TIM PWM, STBY = GPIO enable
2
void motor_set_tb(int16_t speed) {
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    if (speed > 0) {
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        GPIOA->BSRR = (1u << 0);    // AIN1=1
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        GPIOA->BSRR = (1u << 17);   // AIN2=0
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        TIM2->CCR1 = (uint32_t)speed * 4200 / 1000;
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    } else if (speed < 0) {
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        GPIOA->BSRR = (1u << 16);   // AIN1=0
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        GPIOA->BSRR = (1u << 1);    // AIN2=1
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        TIM2->CCR1 = (uint32_t)(-speed) * 4200 / 1000;
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    } else {
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        // brake
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        GPIOA->BSRR = (1u << 0) | (1u << 1);
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        TIM2->CCR1 = 0;
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    }
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}

1
static int16_t current_speed;
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static int16_t target_speed;
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#define RAMP_STEP 10   // per 10 ms
4

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void motor_set_target(int16_t s) { target_speed = s; }
6

7
// 10 ms 주기 호출
8
void motor_ramp_tick(void) {
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    if (current_speed < target_speed) {
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        current_speed += RAMP_STEP;
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        if (current_speed > target_speed) current_speed = target_speed;
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    } else if (current_speed > target_speed) {
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        current_speed -= RAMP_STEP;
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        if (current_speed < target_speed) current_speed = target_speed;
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    }
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    motor_set(current_speed);
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}

1
// PA2 = ADC1_IN2, shunt 0.1Ω → amp ×10 → 1V/A
2
uint16_t motor_current_ma(void) {
3
    ADC1->SQR3 = 2;                  // channel 2
4
    ADC1->CR2 |= ADC_CR2_SWSTART;
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    while (!(ADC1->SR & ADC_SR_EOC));
6
    uint16_t adc = ADC1->DR;          // 0~4095
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    // V = adc / 4095 * 3.3
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    // I = V (since 1V/A)
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    return adc * 3300u / 4095u;       // mA
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}
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12
// 보호: over-current cut-off
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void motor_protect_task(void) {
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    if (motor_current_ma() > 2000) {
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        motor_coast();
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        printf("Over-current trip!\n");
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    }
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}