1.定义一个空的指针函数 指针函数的参数是uint8_t 类型ch
typedef void (* usart_recv_callback)(uint8_t ch);
2.声明这个类型
usart_recv_callback usart1_recv_cb;
3.串口配置时,一个形参为串口中断接收回调
void Usart_Config(USART_TypeDef* USARTx, uint32_t baudRate, usart_recv_callback cb)
{
GPIO_InitTypeDef GPIO_InitStructure; USART_InitTypeDef USART_InitStructure; NVIC_InitTypeDef NVIC_InitStructure; if(USARTx == USART1) { usart1_recv_cb = cb; RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE); /* Configure USART1 Tx (PA.09) as alternate function push-pull */ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; GPIO_Init(GPIOA, &GPIO_InitStructure); /* Configure USART1 Rx (PA.10) as input floating */ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; GPIO_Init(GPIOA, &GPIO_InitStructure); USART_InitStructure.USART_BaudRate = baudRate; USART_InitStructure.USART_WordLength = USART_WordLength_8b; USART_InitStructure.USART_StopBits = USART_StopBits_1; USART_InitStructure.USART_Parity = USART_Parity_No; USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None; USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; USART_Init(USART1, &USART_InitStructure); if(cb) { USART_ITConfig(USART1, USART_IT_RXNE, ENABLE); /* Enable the USARTy Interrupt */ NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn; NVIC_InitStructure.NVIC_IRQChannelPReemptionPriority = 0; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure); } USART_Cmd(USART1, ENABLE); }
}
分析:usart1_recv_cb = cb;这句语句是将形参指针函数 cb 赋值给 usart1_recv_cb
if(cb):是判断回调函数指针是否为空,如果不为空则中断初始化
4.串口中断函数
void USART1_IRQHandler(void){ uint8_t ch; if(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET) { /* Read one byte from the receive data register */ ch = USART_ReceiveData(USART1); usart1_recv_cb(ch); USART_ClearITPendingBit(USART1, USART_IT_RXNE); }}
分析:将串口1中断接收到的值赋值给ch,然后ch作为usart1_recv_cb函数的输入参数
5.
void HCHO_Test(uint8_t recv_data){if((sensorstr.hcho_addr == 0) && (recv_data != 0xff)){ sensorstr.hcho_addr = 0;return;}if((sensorstr.hcho_addr == 1) && (recv_data != 0x17)){ sensorstr.hcho_addr = 0;return;}if((sensorstr.hcho_addr == 2) && (recv_data != 0x04)){ sensorstr.hcho_addr = 0;return;} sensorstr.hcho_packet[sensorstr.hcho_addr++] = recv_data;}
分析:void HCHO_Test(uint8_t recv_data)函数就是我们所说的回调函数,此函数和 1.里所定义的void (* usart_recv_callback)(uint8_t ch)函数指针是对应的。
6.
int main(void)
{
Usart_Config(PM_UART, 9600, PM_Test);
}
PM_Test函数首地址就是usart_recv_callback cb的形参
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