关于STM32的头文件

只看该作者 · 2012-5-12 11:35

在头文件里面，以stm32f10x_usart.h为例
比方说，对那个USART_MODE进行宏定义的时候，有三个宏定义
#define USART_Mode_Rx ((uint16_t)0x0004)
#define USART_Mode_Tx ((uint16_t)0x0008)
#define IS_USART_MODE(MODE) ((((MODE) & (uint16_t)0xFFF3) == 0x00) && ((MODE) != (uint16_t)0x00))

请问一下，，第三个宏定义是什么个意思呢？

因为我在定义结构体USART_InitTypeDef USART_STR时，
使用USART_STR.IS_USART_MODE 时报错，，，

谢谢。

只看该作者 · 2012-5-12 12:00

从名称直译是：是串口模式吗？

只看该作者 · 2012-5-12 12:18

2# aozima
:(

只看该作者 · 2012-5-12 23:10

IS_USART_MODE(MODE)只是实现对MODE这个参数的检查用的吧，
USART_InitTypeDef这个结构体里面并没有IS_USART_MODE这个元素，当然会报错呀。
库文件里是这么定义的：
typedef struct
{
  uint32_t USART_BaudRate;          /*!< This member configures the USART communication baud rate.
                                       The baud rate is computed using the following formula:
                                          - IntegerDivider = ((PCLKx) / (16 * (USART_InitStruct->USART_BaudRate)))
                                          - FractionalDivider = ((IntegerDivider - ((u32) IntegerDivider)) * 16) + 0.5 */

  uint16_t USART_WordLength;       /*!< Specifies the number of data bits transmitted or received in a frame.
                                       This parameter can be a value of @ref USART_Word_Length */

  uint16_t USART_StopBits;          /*!< Specifies the number of stop bits transmitted.
                                       This parameter can be a value of @ref USART_Stop_Bits */

  uint16_t USART_Parity;             /*!< Specifies the parity mode.
                                       This parameter can be a value of @ref USART_Parity
                                       @note When parity is enabled, the computed parity is inserted
                                             at the MSB position of the transmitted data (9th bit when
                                             the word length is set to 9 data bits; 8th bit when the
                                             word length is set to 8 data bits). */

  uint16_t USART_Mode;             /*!< Specifies wether the Receive or Transmit mode is enabled or disabled.
                                       This parameter can be a value of @ref USART_Mode */

  uint16_t USART_HardwareFlowControl; /*!< Specifies wether the hardware flow control mode is enabled
                                       or disabled.
                                       This parameter can be a value of @ref USART_Hardware_Flow_Control */
} USART_InitTypeDef;