- *软件串口的实现(IO模拟串口)
- * 波特率：9600 1-8-N
- * TXD : PC13
- * RXD : PB14
- * 使用外部中断对RXD的下降沿进行触发，使用定时器4按照9600波特率进行定时数据接收。
- * Demo功能: 接收11个数据，然后把接收到的数据发送出去
- */
- #define OI_TXD PCout(13)
- #define OI_RXD PBin(14)
- #define BuadRate_9600 100
- u8 len = 0; //接收计数
- u8 USART_buf[11]; //接收缓冲区
- enum{
- COM_START_BIT,
- COM_D0_BIT,
- COM_D1_BIT,
- COM_D2_BIT,
- COM_D3_BIT,
- COM_D4_BIT,
- COM_D5_BIT,
- COM_D6_BIT,
- COM_D7_BIT,
- COM_STOP_BIT,
- };
- u8 recvStat = COM_STOP_BIT;
- u8 recvData = 0;
- void IO_TXD(u8 Data)
- {
- u8 i = 0;
- OI_TXD = 0;
- delay_us(BuadRate_9600);
- for(i = 0; i < 8; i++)
- {
- if(Data&0x01)
- OI_TXD = 1;
- else
- OI_TXD = 0;
- delay_us(BuadRate_9600);
- Data = Data>>1;
- }
- OI_TXD = 1;
- delay_us(BuadRate_9600);
- }
- void USART_Send(u8 *buf, u8 len)
- {
- u8 t;
- for(t = 0; t < len; t++)
- {
- IO_TXD(buf[t]);
- }
- }
- void IOConfig(void)
- {
- GPIO_InitTypeDef GPIO_InitStructure;
- NVIC_InitTypeDef NVIC_InitStructure;
- EXTI_InitTypeDef EXTI_InitStruct;
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO|RCC_APB2Periph_GPIOB|RCC_APB2Periph_GPIOC, ENABLE); //使能PB,PC端口时钟
- //SoftWare Serial TXD
- GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13;
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP; //推挽输出
- GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //IO口速度为50MHz
- GPIO_Init(GPIOC, &GPIO_InitStructure);
- GPIO_SetBits(GPIOC,GPIO_Pin_13);
- //SoftWare Serial RXD
- GPIO_InitStructure.GPIO_Pin = GPIO_Pin_14;
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
- GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
- GPIO_Init(GPIOB, &GPIO_InitStructure);
- GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource14);
- EXTI_InitStruct.EXTI_Line = EXTI_Line14;
- EXTI_InitStruct.EXTI_Mode=EXTI_Mode_Interrupt;
- EXTI_InitStruct.EXTI_Trigger=EXTI_Trigger_Falling; //下降沿触发中断
- EXTI_InitStruct.EXTI_LineCmd=ENABLE;
- EXTI_Init(&EXTI_InitStruct);
- NVIC_InitStructure.NVIC_IRQChannel= EXTI15_10_IRQn ;
- NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=2;
- NVIC_InitStructure.NVIC_IRQChannelSubPriority =2;
- NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
- NVIC_Init(&NVIC_InitStructure);
- }
- void TIM4_Int_Init(u16 arr,u16 psc)
- {
- TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
- NVIC_InitTypeDef NVIC_InitStructure;
- RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE); //时钟使能
- //定时器TIM4初始化
- TIM_TimeBaseStructure.TIM_Period = arr; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值
- TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值
- TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; //设置时钟分割:TDTS = Tck_tim
- TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上计数模式
- TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure); //根据指定的参数初始化TIMx的时间基数单位
- TIM_ClearITPendingBit(TIM4, TIM_FLAG_Update);
- TIM_ITConfig(TIM4,TIM_IT_Update,ENABLE ); //使能指定的TIM3中断,允许更新中断
- //中断优先级NVIC设置
- NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQn; //TIM4中断
- NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1; //先占优先级1级
- NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; //从优先级1级
- NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道被使能
- NVIC_Init(&NVIC_InitStructure); //初始化NVIC寄存器
- }
- int main(void)
- {
- NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);//设置中断优先级分组为组2：2位抢占优先级，2位响应优先级
- delay_init();
- IOConfig();
- TIM4_Int_Init(107, 71); //1M计数频率
- while(1)
- {
- if(len > 10)
- {
- len = 0;
- USART_Send(USART_buf,11);
- }
- }
- }
- void EXTI15_10_IRQHandler(void)
- {
- if(EXTI_GetFlagStatus(EXTI_Line14) != RESET)
- {
- if(OI_RXD == 0)
- {
- if(recvStat == COM_STOP_BIT)
- {
- recvStat = COM_START_BIT;
- TIM_Cmd(TIM4, ENABLE);
- }
- }
- EXTI_ClearITPendingBit(EXTI_Line14);
- }
- }
- void TIM4_IRQHandler(void)
- {
- if(TIM_GetFlagStatus(TIM4, TIM_FLAG_Update) != RESET)
- {
- TIM_ClearITPendingBit(TIM4, TIM_FLAG_Update);
- recvStat++;
- if(recvStat == COM_STOP_BIT)
- {
- TIM_Cmd(TIM4, DISABLE);
- USART_buf[len++] = recvData;
- return;
- }
- if(OI_RXD)
- {
- recvData |= (1 << (recvStat - 1));
- }else{
- recvData &= ~(1 << (recvStat - 1));
- }
- }
- }
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