基于ATM32F103C8T6写一个NEC红外遥控程序，PB9为信号接收引脚，

好的，以下是ATM32F103C8T6上的NEC红外遥控程序示例：

#include "stm32f10x.h"

#define IR_PIN GPIO_Pin_9
#define IR_GPIO GPIOB

volatile uint16_t irBuffer[32];
volatile uint8_t irData[4];

void IR_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

    GPIO_InitStructure.GPIO_Pin = IR_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(IR_GPIO, &GPIO_InitStructure);

    NVIC_InitTypeDef NVIC_InitStructure;
    NVIC_InitStructure.NVIC_IRQChannel = EXTI9_5_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    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);
}

void EXTI9_5_IRQHandler(void)
{
    static uint8_t flag = 0;
    static uint8_t dataCount = 0;
    static uint16_t lastValue = 0;
    uint16_t irValue = TIM2->CNT;

    if (flag == 0) {
        if (irValue < 8000 || irValue > 12000) {
            return;
        }
        flag = 1;
    } else if (flag == 1) {
        if (irValue < 3500 || irValue > 4500) {
            flag = 0;
            return;
        }
        flag = 2;
    } else if (flag == 2) {
        if (irValue < 500 || irValue > 1500) {
            flag = 0;
            return;
        }
        lastValue = irValue;
        flag = 3;
    } else if (flag == 3) {
        if (irValue < 500 || irValue > 1500) {
            flag = 0;
            return;
        }
        irBuffer[dataCount++] = (irValue + lastValue) / 2;
        lastValue = irValue;
        if (dataCount >= 32) {
            flag = 4;
        }
    } else if (flag == 4) {
        if (irValue < 500 || irValue > 1500) {
            flag = 0;
            dataCount = 0;
            return;
        }
        irBuffer[dataCount++] = (irValue + lastValue) / 2;
        lastValue = irValue;
        if (dataCount >= 32) {
            for (int i = 0; i < 4; i++) {
                uint8_t byte = 0;
                for (int j = 0; j < 8; j++) {
                    if (irBuffer[i * 8 + j + 1] > 1000) {
                        byte |= (1 << (7 - j));
                    }
                }
                irData[i] = byte;
            }
            flag = 0;
            dataCount = 0;
        }
    }

    EXTI_ClearITPendingBit(EXTI_Line9);
}

int main(void)
{
    IR_Init();

    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
    TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
    TIM_TimeBaseStructure.TIM_Prescaler = 71;
    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
    TIM_Cmd(TIM2, ENABLE);

    while (1) {
        // 等待中断处理
    }
}

代码的主要思路是使用外部中断来捕获红外信号，然后解码得到红外数据。在初始化中，我们使用`EXTI`和`TIM2`来设置PB9引脚的中断和计时器。在中断处理程序中，我们按照NEC红外协议对红外信号进行解码，得到4个字节的红外数据。最后，在主循环中等待中断处理程序对红外数据进行处理。

需要注意的是，在使用该代码时，需要将PB9引脚连接到红外接收器的信号引脚上。并且，由于ATM32F103C8T6没有内置的USB转串口芯片，因此需要使用外部的USB转串口模块来输出数据。