使用stm32f103实现频率计设计。使用2个通用定时器，一个计时，另一个对外部信号计数，在oled上显示出计数值和频率值。并且将代码以及注释写下

好的，下面是使用STM32F103实现频率计的设计，代码注释已经加上了：

#include "stm32f10x.h"
#include "oled.h"
#include "delay.h"

// 定义计时器
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_ICInitTypeDef  TIM_ICInitStructure;

// 定义计数值和频率值
uint32_t IC2Value = 0;
uint32_t IC1Value = 0;
uint32_t CaptureNumber = 0;
uint32_t Capture = 0;
uint32_t TIM1Freq = 0;

int main(void)
{
    // 初始化OLED屏幕
    OLED_Init();
    OLED_Clear();

    // 初始化计时器2
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
    TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
    TIM_TimeBaseStructure.TIM_Prescaler = 71;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

    // 初始化计时器1
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
    TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
    TIM_TimeBaseStructure.TIM_Prescaler = 71;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);

    // 初始化输入捕获2
    TIM_ICInitStructure.TIM_Channel = 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);

    // 初始化输入捕获1
    TIM_ICInitStructure.TIM_Channel = TIM_Channel_1;
    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(TIM1, &TIM_ICInitStructure);

    // 开启输入捕获2中断
    TIM_ITConfig(TIM2, TIM_IT_CC2, ENABLE);

    // 开启计时器2和计时器1
    TIM_Cmd(TIM2, ENABLE);
    TIM_Cmd(TIM1, ENABLE);

    while (1)
    {
        // 显示计数值和频率值
        OLED_ShowString(0, 0, "Count:     Hz:");
        OLED_ShowNum(60, 0, CaptureNumber, 5, 16);
        OLED_ShowNum(120, 0, TIM1Freq, 5, 16);
    }
}

// 计数器中断服务程序
void TIM2_IRQHandler(void)
{
    if (TIM_GetITStatus(TIM2, TIM_IT_CC2) == SET)
    {
        TIM_ClearITPendingBit(TIM2, TIM_IT_CC2);

        // 获取计数值
        IC2Value = TIM_GetCapture2(TIM2);

        if (CaptureNumber == 0)
        {
            // 获取第一次计数的时间
            Capture = IC2Value;
            CaptureNumber = 1;
        }
        else if (CaptureNumber == 1)
        {
            // 计算出两次计数的时间差
            TIM1Freq = SystemCoreClock / ((IC2Value - Capture + 1) * 2);
            CaptureNumber = 0;
        }
    }
}

注：以上代码仅供参考，具体实现需要根据实际情况进行调整。