PWM frequency: 50Hz

High level time for full throttle: 2ms

High level time for zero throttle: 1ms

Brushless ESC calibration process:

// 50Hz 20000div 0.001ms/div
// 1ms ~ 2ms <=> 1000 ~ 2000
void esc_calibrate()
{
    u8 i;
    u16 j;
    uint8_t buff[16];

    LOGI("Step 1. Push the throttle to the max\n");
    // Channel_X(TIM2,MOTOR1_PWMCH,5000);	//油门推到最大
    TIM3->CCR3 = 2000;

    LOGI("Step 2. Power up the ESC, waiting for two beeps and goto next step ASAP\n");
    // UartGetByte(USART1);	//等待上电
    while (1) {
        int len = SEGGER_RTT_Read(0, buff, 16);
        if (len && buff[0] == 'a') {
            break;
        }
    }

    LOGI("Step 3. Push the throttle to min, calibration's after three beeps\n");
    // Channel_X(TIM2,MOTOR1_PWMCH,2000);	//油门推到最小
    TIM3->CCR3 = 1000;

    LOGI("Step 4. Test\n");
    // UartGetByte(USART1);	//等待上电
    while (1) {
        int len = SEGGER_RTT_Read(0, buff, 16);
        if (len && buff[0] == 'a') {
            break;
        }
    }

    for(j=800;j<1100;j++)
    {
        LOGI("%d ",j);
        // Channel_X(TIM2,MOTOR1_PWMCH,i);						//油门推到最小
        TIM3->CCR3 = j;
        delay_ms(20);
    }

    delay_ms(5000);
    TIM3->CCR3 = 1000;

    while(1);
}