STM32 - HAL库UART串口

1.串口初始化配置

/*******************************************************************************
Function: BSP_UART_Init 
Description: 串口初始化
Input:  instance 串口号baudRate: 波特率
Output: 无
Return: 无
*******************************************************************************/
void BSP_UART_Init(USART_TypeDef *instance, uint32_t baudRate)
{if (instance == USART1){huart1.Instance = USART1;huart1.Init.BaudRate = baudRate;huart1.Init.WordLength = UART_WORDLENGTH_8B;huart1.Init.StopBits = UART_STOPBITS_1;huart1.Init.Parity = UART_PARITY_NONE;huart1.Init.Mode = UART_MODE_TX_RX;huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;huart1.Init.OverSampling = UART_OVERSAMPLING_16;if (HAL_UART_Init(&s_uart1) != HAL_OK){Error_Handler();}}else if (instance == USART2){huart2.Instance = USART2;huart2.Init.BaudRate = baudRate;huart2.Init.WordLength = UART_WORDLENGTH_8B;huart2.Init.StopBits = UART_STOPBITS_1;huart2.Init.Parity = UART_PARITY_NONE;huart2.Init.Mode = UART_MODE_TX_RX;huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;huart2.Init.OverSampling = UART_OVERSAMPLING_16;if (HAL_UART_Init(&s_uart2) != HAL_OK){Error_Handler();}}else if (instance == USART3){huart3.Instance = USART3;huart3.Init.BaudRate = baudRate;huart3.Init.WordLength = UART_WORDLENGTH_8B;huart3.Init.StopBits = UART_STOPBITS_1;huart3.Init.Parity = UART_PARITY_NONE;huart3.Init.Mode = UART_MODE_TX_RX;huart3.Init.HwFlowCtl = UART_HWCONTROL_NONE;huart3.Init.OverSampling = UART_OVERSAMPLING_16;if (HAL_UART_Init(&s_uart3) != HAL_OK){Error_Handler();}}
}

1.1 外设句柄 xxx_HandleTypeDef

UART_HandleTypeDef huart1;
UART_HandleTypeDef huart2;

第一行表示：名为huart1的、类型为UART_HandleTypeDef型的一个结构体

第二行表示：名为huart2的、类型为UART_HandleTypeDef型的一个结构体

1.2 __UART_HandleTypeDef

stm32f1xx_hal_uart.h文件

代码类型___UART_HandleTypeDef,别名UART_HandleTypeDef。

/*** @brief  UART handle Structure definition*/
typedef struct __UART_HandleTypeDef
{USART_TypeDef                 *Instance;        /*!< UART registers base address        */UART_InitTypeDef              Init;             /*!< UART communication parameters      */uint8_t                       *pTxBuffPtr;      /*!< Pointer to UART Tx transfer Buffer */uint16_t                      TxXferSize;       /*!< UART Tx Transfer size              */__IO uint16_t                 TxXferCount;      /*!< UART Tx Transfer Counter           */uint8_t                       *pRxBuffPtr;      /*!< Pointer to UART Rx transfer Buffer */uint16_t                      RxXferSize;       /*!< UART Rx Transfer size              */__IO uint16_t                 RxXferCount;      /*!< UART Rx Transfer Counter           */DMA_HandleTypeDef             *hdmatx;          /*!< UART Tx DMA Handle parameters      */DMA_HandleTypeDef             *hdmarx;          /*!< UART Rx DMA Handle parameters      */HAL_LockTypeDef               Lock;             /*!< Locking object                     */__IO HAL_UART_StateTypeDef    gState;           /*!< UART state information related to global Handle managementand also related to Tx operations.This parameter can be a value of @ref HAL_UART_StateTypeDef */__IO HAL_UART_StateTypeDef    RxState;          /*!< UART state information related to Rx operations.This parameter can be a value of @ref HAL_UART_StateTypeDef */__IO uint32_t                 ErrorCode;        /*!< UART Error code    

huart1.Instance = USART1;这行代码，首先第一点huart1.Instance表示的是结构体huart1中的成员变量Instance。

1.3 Instance成员=USART1

#define USART1              ((USART_TypeDef *)USART1_BASE)

USART1是一个宏。

这个宏是将USART1_BASE（常量）强制转换为USART_TypeDef型结构体指针。

常量强制转化为一个结构体指针，该常量为结构体的起始地址。

USART1_BASE被强制转换为USART_TypeDef的起始地址，内存空间将以USART_TypeDef类型进行构建，首址为USART1_BASE，空间内有成员，按其固有类型顺序依次分配内存空间。

根据HAL库的注释，可以知道Instance指向的也是uart寄存器组的基地址。