本篇文章为大家展示了STM32怎么用IO口模拟串口，内容简明扼要并且容易理解，绝对能使你眼前一亮，通过这篇文章的详细介绍希望你能有所收获。
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PB12模拟TXD,PB13模拟RXD 发送时序比较单一，按时序图可很快实现。 接收比较复杂这里用定时器TM4的溢出中断和PB13的外部中断配合计算电平时间来获取串口数据。
#define BuadRate_9600 100
u8 len = 0; //接收计数
u8 USART_buf[11]; //接收缓冲区
#define OI_TXD PBout(12)
#define OI_RXD PBin(13)
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 rf315_IoConfig()
{
GPIO_InitTypeDef GPIO_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
EXTI_InitTypeDef EXTI_InitStruct;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO|RCC_APB2Periph_GPIOB, ENABLE); //使能PB,PC端口时钟
//SoftWare Serial TXD
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
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(GPIOB,GPIO_Pin_12);
//SoftWare Serial RXD
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);
GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource13);
EXTI_InitStruct.EXTI_Line = EXTI_Line13;
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
}
void rf315_uart4Init()
{
rf315_IoConfig();
TIM4_Int_Init(107, 71); //1M计数频率
}
void rf315_SendChar(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 rf315_SendData(u8 *buf, u8 len)
{
u8 t;
for(t = 0; t < len; t++)
{
rf315_SendChar(buf[t]);
}
}
void EXTI15_10_IRQHandler(void)
{
if(EXTI_GetFlagStatus(EXTI_Line13) != RESET)
{
if(OI_RXD == 0)
{
if(recvStat == COM_STOP_BIT)
{
recvStat = COM_START_BIT;
TIM_Cmd(TIM4, ENABLE);
}
}
EXTI_ClearITPendingBit(EXTI_Line13);
}
}
u8 rf315_data_need_handler=0;
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;
/*数据协议尾*/
if(USART_buf[len-1]==RF315_PROTOCOL_TAIL)
rf315_data_need_handler=1;
return;
}
if(OI_RXD)
{
recvData |= (1 << (recvStat - 1));
}else{
recvData &= ~(1 << (recvStat - 1));
}
}
}上述内容就是STM32怎么用IO口模拟串口，你们学到知识或技能了吗？如果还想学到更多技能或者丰富自己的知识储备，欢迎关注创新互联行业资讯频道。
