写一个用stm32f407实现将输入信号的幅值，频率，占空比在串口屏上输出的代码

以下是使用STM32F407实现将输入信号的幅值、频率和占空比在串口屏上输出的代码。假设输入信号为PA0引脚上的模拟信号。

#include "stm32f4xx.h"
#include "stdio.h"

#define USARTx                           USART1
#define USARTx_CLK                       RCC_APB2Periph_USART1
#define USARTx_TX_PIN                    GPIO_Pin_9
#define USARTx_TX_GPIO_PORT              GPIOA
#define USARTx_TX_GPIO_CLK               RCC_AHB1Periph_GPIOA
#define USARTx_TX_SOURCE                 GPIO_PinSource9
#define USARTx_TX_AF                     GPIO_AF_USART1
#define USARTx_RX_PIN                    GPIO_Pin_10
#define USARTx_RX_GPIO_PORT              GPIOA
#define USARTx_RX_GPIO_CLK               RCC_AHB1Periph_GPIOA
#define USARTx_RX_SOURCE                 GPIO_PinSource10
#define USARTx_RX_AF                     GPIO_AF_USART1
#define USARTx_IRQn                      USART1_IRQn

void USART_Config(void);
void GPIO_Config(void);
void TIM_Config(void);

volatile uint32_t m_u32Capture1 = 0;
volatile uint32_t m_u32Capture2 = 0;
volatile uint32_t m_u32Frequency = 0;

int main(void)
{
    USART_Config();
    GPIO_Config();
    TIM_Config();

    while (1)
    {
        uint16_t u16PulseWidth = m_u32Capture2 - m_u32Capture1;
        float fDutyCycle = (float)u16PulseWidth / (float)m_u32Frequency * 100.0f;
        printf("Amplitude: %d\n", (uint16_t)(4096.0f * (float)ADC1->DR / 4096.0f));
        printf("Frequency: %d Hz\n", m_u32Frequency);
        printf("Duty Cycle: %.1f %%\n", fDutyCycle);
    }
}

void USART_Config(void)
{
    RCC_AHB1PeriphClockCmd(USARTx_TX_GPIO_CLK | USARTx_RX_GPIO_CLK, ENABLE);
    RCC_APB2PeriphClockCmd(USARTx_CLK, ENABLE);

    GPIO_InitTypeDef GPIO_InitStructure;

    GPIO_InitStructure.GPIO_Pin = USARTx_TX_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(USARTx_TX_GPIO_PORT, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = USARTx_RX_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(USARTx_RX_GPIO_PORT, &GPIO_InitStructure);

    GPIO_PinAFConfig(USARTx_TX_GPIO_PORT, USARTx_TX_SOURCE, USARTx_TX_AF);
    GPIO_PinAFConfig(USARTx_RX_GPIO_PORT, USARTx_RX_SOURCE, USARTx_RX_AF);

    USART_InitTypeDef USART_InitStructure;

    USART_InitStructure.USART_BaudRate = 115200;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    USART_InitStructure.USART_StopBits = USART_StopBits_1;
    USART_InitStructure.USART_Parity = USART_Parity_No;
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStructure.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;
    USART_Init(USARTx, &USART_InitStructure);

    USART_Cmd(USARTx, ENABLE);
}

void GPIO_Config(void)
{
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

    GPIO_InitTypeDef GPIO_InitStructure;

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_Init(GPIOA, &GPIO_InitStructure);
}

void TIM_Config(void)
{
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
    TIM_TimeBaseStructure.TIM_Prescaler = 84 - 1;
    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

    TIM_ICInitTypeDef TIM_ICInitStructure;
    TIM_ICInitStructure.TIM_Channel = TIM_Channel_1 | TIM_Channel_2;
    TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
    TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
    TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
    TIM_ICInitStructure.TIM_ICFilter = 0x0;
    TIM_ICInit(TIM2, &TIM_ICInitStructure);

    NVIC_InitTypeDef NVIC_InitStructure;
    NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    TIM_Cmd(TIM2, ENABLE);
    TIM_ITConfig(TIM2, TIM_IT_CC1 | TIM_IT_CC2, ENABLE);
}

void TIM2_IRQHandler(void)
{
    if (TIM_GetITStatus(TIM2, TIM_IT_CC1) == SET)
    {
        m_u32Capture1 = TIM_GetCapture1(TIM2);
        TIM_SetCounter(TIM2, 0);
        TIM_ClearITPendingBit(TIM2, TIM_IT_CC1);
    }

    if (TIM_GetITStatus(TIM2, TIM_IT_CC2) == SET)
    {
        m_u32Capture2 = TIM_GetCapture2(TIM2);
        m_u32Frequency = SystemCoreClock / TIM_GetCapture1(TIM2);
        TIM_ClearITPendingBit(TIM2, TIM_IT_CC2);
    }
}

这个代码需要通过PA0引脚输入一个模拟信号，然后使用定时器2来捕捉输入信号的上升沿和下降沿。在捕捉到两个边沿后，我们可以计算输入信号的周期，频率和占空比，并通过串口将这些信息输出。