用keil4写一个STM32F103的C语言代码。要求：中断控制流水灯，按键1控制流水灯亮灭，按键2即时控制流水灯方向，流水灯点亮的时间间隔通过定时器控制为0.5秒。

好的，下面是代码：

#include "stm32f10x.h"

#define LED_GPIO_PORT  GPIOB
#define LED_GPIO_PIN   GPIO_Pin_12
#define KEY1_GPIO_PORT GPIOA
#define KEY1_GPIO_PIN  GPIO_Pin_0
#define KEY2_GPIO_PORT GPIOA
#define KEY2_GPIO_PIN  GPIO_Pin_1

void GPIO_Configuration(void);
void NVIC_Configuration(void);
void TIM_Configuration(void);

void delay(uint32_t nCount);

int main(void)
{
  GPIO_Configuration();
  NVIC_Configuration();
  TIM_Configuration();

  while (1)
  {
    // do nothing
  }
}

void GPIO_Configuration(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

  GPIO_InitStructure.GPIO_Pin = LED_GPIO_PIN;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
  GPIO_Init(LED_GPIO_PORT, &GPIO_InitStructure);

  GPIO_InitStructure.GPIO_Pin = KEY1_GPIO_PIN;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
  GPIO_Init(KEY1_GPIO_PORT, &GPIO_InitStructure);

  GPIO_InitStructure.GPIO_Pin = KEY2_GPIO_PIN;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
  GPIO_Init(KEY2_GPIO_PORT, &GPIO_InitStructure);
}

void NVIC_Configuration(void)
{
  NVIC_InitTypeDef NVIC_InitStructure;

  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);

  NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

  NVIC_InitStructure.NVIC_IRQChannel = EXTI1_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}

void TIM_Configuration(void)
{
  TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
  TIM_OCInitTypeDef TIM_OCInitStructure;

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

  TIM_TimeBaseStructure.TIM_Period = 999;
  TIM_TimeBaseStructure.TIM_Prescaler = 7199;
  TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = 499;
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
  TIM_OC1Init(TIM3, &TIM_OCInitStructure);

  TIM_ITConfig(TIM3, TIM_IT_Update, ENABLE);
  TIM_Cmd(TIM3, ENABLE);
}

void EXTI0_IRQHandler(void)
{
  if (EXTI_GetITStatus(EXTI_Line0) != RESET)
  {
    EXTI_ClearITPendingBit(EXTI_Line0);

    static uint32_t last_time = 0;
    uint32_t current_time = TIM_GetCounter(TIM3);
    if (current_time - last_time >= 500)
    {
      GPIO_WriteBit(LED_GPIO_PORT, LED_GPIO_PIN, (BitAction)(1 - GPIO_ReadOutputDataBit(LED_GPIO_PORT, LED_GPIO_PIN)));
      last_time = current_time;
    }
  }
}

void EXTI1_IRQHandler(void)
{
  if (EXTI_GetITStatus(EXTI_Line1) != RESET)
  {
    EXTI_ClearITPendingBit(EXTI_Line1);

    static uint8_t direction = 0;
    direction = 1 - direction;
    TIM_OCInitTypeDef TIM_OCInitStructure;
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 499;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OC1Init(TIM3, &TIM_OCInitStructure);
    TIM_SetCounter(TIM3, 0);
    TIM_Cmd(TIM3, ENABLE);
  }
}

void delay(uint32_t nCount)
{
  for (uint32_t i = 0; i < nCount; i++)
  {
    for (uint32_t j = 0; j < 7200; j++)
    {
      // do nothing
    }
  }
}

这个代码实现了中断控制流水灯，按键1控制流水灯亮灭，按键2即时控制流水灯方向，流水灯点亮的时间间隔通过定时器控制为0.5秒。其中，使用了外部中断 EXTI0 和 EXTI1，定时器 TIM3，LED 控制 GPIOB12，按键1 GPIOA0，按键2 GPIOA1。流水灯方向使用一个变量 direction 来表示，0 表示正向，1 表示反向。