STM32定时器4无法正常工作

Question

STM32C8T6单片机定时器4（TIM4）用不了，在同一个例程中，将TIM4改为TIM3或者TIM2都能实现功能。但是一但改成TIM4就不行了，无论是作为pwm输出，还是编码器输入，都没有一点反映

```c
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB|RCC_APB2Periph_AFIO, ENABLE);
    

    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOB, &GPIO_InitStructure);
        

    TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInitStructure.TIM_Period = 65536 - 1;        //ARR
    TIM_TimeBaseInitStructure.TIM_Prescaler = 1 - 1;        //PSC
    TIM_TimeBaseInitStructure.TIM_RepetitionCounter = 0;
    TIM_TimeBaseInit(TIM4, &TIM_TimeBaseInitStructure);
    
    TIM_ICStructInit(&TIM_ICInitStructure);
    TIM_ICInitStructure.TIM_Channel = TIM_Channel_1;
    TIM_ICInitStructure.TIM_ICFilter = 0xF;
    TIM_ICInit(TIM4, &TIM_ICInitStructure);
    TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;
    TIM_ICInitStructure.TIM_ICFilter = 0xF;
    TIM_ICInit(TIM4, &TIM_ICInitStructure);
    
    TIM_EncoderInterfaceConfig(TIM4, TIM_EncoderMode_TI12, TIM_ICPolarity_Rising, TIM_ICPolarity_Rising);
    
    TIM_Cmd(TIM4, ENABLE);
}

int16_t Encoder2_Get(void)
{
    int16_t Temp;
    Temp = TIM_GetCounter(TIM4);
    TIM_SetCounter(TIM4, 0);
    return Temp;
}

```

Answer 1

确定是c8t6还是c6t6，搞了半天最后发现是c6t6，根本没有定时器4😓