stm32 结构理解

如：stm32l010x4的串口

1、stm32l010x4.h

1.1 串口寄存器定义

首先在stm32l010x4.h 定义寄存器，其形式是结构体，结构体内每个变量都是无符号整型，变量长度等于寄存器所占位数。如串口寄存器USART registers的定义如下。

/** 
  * @brief Universal Synchronous Asynchronous Receiver Transmitter
  */
typedef struct
{
   
  __IO uint32_t CR1;    /*!< USART Control register 1,                 Address offset: 0x00 */ 
  __IO uint32_t CR2;    /*!< USART Control register 2,                 Address offset: 0x04 */ 
  __IO uint32_t CR3;    /*!< USART Control register 3,                 Address offset: 0x08 */
  __IO uint32_t BRR;    /*!< USART Baud rate register,                 Address offset: 0x0C */  
  __IO uint32_t GTPR;   /*!< USART Guard time and prescaler register,  Address offset: 0x10 */
  __IO uint32_t RTOR;   /*!< USART Receiver Time Out register,         Address offset: 0x14 */  
  __IO uint32_t RQR;    /*!< USART Request register,                   Address offset: 0x18 */
  __IO uint32_t ISR;    /*!< USART Interrupt and status register,      Address offset: 0x1C */
  __IO uint32_t ICR;    /*!< USART Interrupt flag Clear register,      Address offset: 0x20 */
  __IO uint32_t RDR;    /*!< USART Receive Data register,              Address offset: 0x24 */
  __IO uint32_t TDR;    /*!< USART Transmit Data register,             Address offset: 0x28 */
} USART_TypeDef;

如__IO uint32_t CR1; /*!< USART Control register 1, Address offset: 0x00 */ 表示在CR1寄存器是32位，且在USART registers的偏移是0x00，与文档相符。

1.2 定义寄存器位

/******************  Bit definition for USART_CR1 register  *******************/
#define USART_CR1_UE_Pos              (0U)    
#define USART_CR1_UE_Msk              (0x1UL << USART_CR1_UE_Pos)               /*!< 0x00000001 */
#define USART_CR1_UE                  USART_CR1_UE_Msk                         /*!< USART Enable */
#define USART_CR1_UESM_Pos            (1U)    
#define USART_CR1_UESM_Msk            (0x1UL << USART_CR1_UESM_Pos)             /*!< 0x00000002 */
#define USART_CR1_UESM                USART_CR1_UESM_Msk                       /*!< USART Enable in STOP Mode */
#define USART_CR1_RE_Pos              (2U)    
#define USART_CR1_RE_Msk              (0x1UL << USART_CR1_RE_Pos)               /*!< 0x00000004 */
#define USART_CR1_RE                  USART_CR1_RE_Msk                         /*!< Receiver Enable */
#define USART_CR1_TE_Pos              (3U)    
#define USART_CR1_TE_Msk              (0x1UL << USART_CR1_TE_Pos)               /*!< 0x00000008 */
#define USART_CR1_TE                  USART_CR1_TE_Msk                         /*!< Transmitter Enable */
#define USART_CR1_IDLEIE_Pos          (4U)    
#define USART_CR1_IDLEIE_Msk          (0x1UL << USART_CR1_IDLEIE_Pos)           /*!< 0x00000010 */
#define USART_CR1_IDLEIE              USART_CR1_IDLEIE_Msk                     /*!< IDLE Interrupt Enable */
#define USART_CR1_RXNEIE_Pos          (5U)    
#define USART_CR1_RXNEIE_Msk          (0x1UL << USART_CR1_RXNEIE_Pos)           /*!< 0x00000020 */
#define USART_CR1_RXNEIE              USART_CR1_RXNEIE_Msk                     /*!< RXNE Interrupt Enable */
#define USART_CR1_TCIE_Pos            (6U)