写一个stm32按键中断程序，按键引脚为PC9

好的，以下是一个简单的stm32按键中断程序，用于检测按下PC9引脚的按钮：

/* Includes */
#include "stm32f10x.h"

/* Function prototypes */
void EXTI9_5_IRQHandler(void);

/* Main program */
int main(void) {
  /* Enable GPIOC clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);

  /* Configure PC9 as input */
  GPIO_InitTypeDef GPIO_InitStructure;
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOC, &GPIO_InitStructure);

  /* Enable SYSCFG clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);

  /* Connect EXTI9 line to PC9 pin */
  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOC, EXTI_PinSource9);

  /* Configure EXTI9 line */
  EXTI_InitTypeDef EXTI_InitStructure;
  EXTI_InitStructure.EXTI_Line = EXTI_Line9;
  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
  EXTI_InitStructure.EXTI_LineCmd = ENABLE;
  EXTI_Init(&EXTI_InitStructure);

  /* Enable EXTI9 interrupt */
  NVIC_InitTypeDef NVIC_InitStructure;
  NVIC_InitStructure.NVIC_IRQChannel = EXTI9_5_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x00;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x00;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

  while (1) {
    /* Main loop does nothing */
  }
}

/* EXTI interrupt handler */
void EXTI9_5_IRQHandler(void) {
  /* Clear EXTI9 interrupt flag */
  EXTI_ClearITPendingBit(EXTI_Line9);

  /* Do something when button is pressed */
}

请注意，这是一个基本的示例代码，可能需要根据您的具体需要进行修改和调整。