原创 STM32最小系统也跑FreeRTOS----IAR (原创)---接上篇

下载了FreeRTOS-v5.02后,解压, 由于手头没有STM32的开发板,一直在用当时ST做活动时送的那个最小系统,看过我博客的朋友应该见过一个图,只引出了串口与USB口.

这里我们要关注的目录有:

这里主要讲的是要把freertos在最小系统上跑起来,主要需处理的是串口驱动相关部分,

根据我在串口控制台的方法,把最小系统上的串口驱动起来,这里有些不同,这里发送接收都采用中断方式,驱动设置如下:

/* Configure USARTx_Tx as alternate function push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_TxPin;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(GPIOx, &GPIO_InitStructure);
       
/* Configure USARTx_Rx as input floating */
GPIO_InitStructure.GPIO_Pin = GPIO_RxPin;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOx, &GPIO_InitStructure);
       
USART_InitStructure.USART_BaudRate = ulWantedBaud;
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_InitStructure.USART_Clock = USART_Clock_Disable;
USART_InitStructure.USART_CPOL = USART_CPOL_Low;
USART_InitStructure.USART_CPHA = USART_CPHA_2Edge;
USART_InitStructure.USART_LastBit = USART_LastBit_Disable;
  
USART_Init( USARTx, &USART_InitStructure );  
USART_ITConfig( USARTx, USART_IT_RXNE, ENABLE );
USART_Cmd( USARTx, ENABLE ); 
  
NVIC_InitStructure.NVIC_IRQChannel = USARTx_IRQChannel;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);  

中断处理如下： 串口发达接收都增加一个环形缓冲队列,参照serial.c更改即可.
if( USART_GetITStatus( USARTx, USART_IT_TXE ) == SET )
{
    if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken )
                    == pdTRUE )
         USART_SendData( USARTx, cChar );
    else
         USART_ITConfig( USARTx, USART_IT_TXE, DISABLE );  
}
if( USART_GetITStatus( USARTx, USART_IT_RXNE ) == SET )
{
    cChar = USART_ReceiveData( USARTx );
    xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
} 
portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );

然后利用FreeRTOS提供的互斥信号量封装串口发送函数,如下:

// taskENTER_CRITICAL(); // 20080808
    if(uartMutexHandle!=NULL)
    {
//xQueueTakeMutexRecursive( xQueueHandle xMutex, portTickType xBlockTime );
//xQueueGiveMutexRecursive( xQueueHandle xMutex );
        if(xQueueTakeMutexRecursive(uartMutexHandle,(portTickType)10)==pdTRUE)
        {
         pxNext = ( signed portCHAR * ) pcString;
         while( *pxNext )
         {
          xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
          pxNext++;
         }
         xQueueGiveMutexRecursive(uartMutexHandle);
        }
    }
// taskEXIT_CRITICAL();

初始化时创建互斥信号量: uartMutexHandle = xSemaphoreCreateMutex(); // 20080815