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都能访问串口的SR寄存器
不同点
USART_GetFlagStatus(USART_TypeDef USARTx, uint16_t USART_FLAG)#xff1a;* 该函数只判断标志位#xff08;访问串口的SR寄存器#xff09;。在没有使能…
文章目录共同点不同点USART_GetITStatus函数详解USART_GetFlagStatus函数共同点
都能访问串口的SR寄存器
不同点
USART_GetFlagStatus(USART_TypeDef USARTx, uint16_t USART_FLAG)* 该函数只判断标志位访问串口的SR寄存器。在没有使能相应的中断函数时通常使用该函数来判断标志位是否置1 USART_GetITStatus(USART_TypeDef USARTx, uint16_t USART_IT) * 不仅会判断标志位是否置1访问串口的SR寄存器同时还会判断是否使能了相应的中断访问串口的CR1寄存器。所以在串口中断函数中如果要获取中断标志位通常使用该函数。USART_GetITStatus判定的是事件标志和使能控制位这两个位同时为1返回值才为1
USART_GetITStatus函数详解
#define USART_IT_PE ((uint16_t)0x0028)
#define USART_IT_TXE ((uint16_t)0x0727)
#define USART_IT_TC ((uint16_t)0x0626)
#define USART_IT_RXNE ((uint16_t)0x0525)
#define USART_IT_ORE_RX ((uint16_t)0x0325) /* In case interrupt is generated if the RXNEIE bit is set */
#define USART_IT_IDLE ((uint16_t)0x0424)
#define USART_IT_LBD ((uint16_t)0x0846)
#define USART_IT_CTS ((uint16_t)0x096A)
#define USART_IT_ERR ((uint16_t)0x0060)
#define USART_IT_ORE_ER ((uint16_t)0x0360) /* In case interrupt is generated if the EIE bit is set */
#define USART_IT_NE ((uint16_t)0x0260)
#define USART_IT_FE ((uint16_t)0x0160)ITStatus USART_GetITStatus(USART_TypeDef* USARTx, uint16_t USART_IT)
{uint32_t bitpos 0x00, itmask 0x00, usartreg 0x00;ITStatus bitstatus RESET;/* Check the parameters */assert_param(IS_USART_ALL_PERIPH(USARTx));assert_param(IS_USART_GET_IT(USART_IT)); /* The CTS interrupt is not available for UART4 and UART5 */ if (USART_IT USART_IT_CTS){assert_param(IS_USART_1236_PERIPH(USARTx));} /* Get the USART register index */usartreg (((uint8_t)USART_IT) 0x05);/* Get the interrupt position */itmask USART_IT IT_MASK;itmask (uint32_t)0x01 itmask;if (usartreg 0x01) /* The IT is in CR1 register */{itmask USARTx-CR1;}else if (usartreg 0x02) /* The IT is in CR2 register */{itmask USARTx-CR2;}else /* The IT is in CR3 register */{itmask USARTx-CR3;}bitpos USART_IT 0x08;bitpos (uint32_t)0x01 bitpos;bitpos USARTx-SR;if ((itmask ! (uint16_t)RESET)(bitpos ! (uint16_t)RESET)){bitstatus SET;}else{bitstatus RESET;}return bitstatus;
}以RXNE为例 一开始是把USART_IT_RXNE 0x0505写成2进制然后只要它的低八位然后低八位右移5位然后得到usartreg的值为0b001然后单击鼠标可以找到IT_MASK的值它与我们的USART_IT相与得到它的值为5接下来就是IT_MASK等于0x01左移5位为什么是5位因为要判定RXNEIE,他就是bit5。我们得到了IT_MASK的第5位为1然后和CR1寄存器相与进而判定RXNEIE是不是1itmask USARTx-CR1;也就是判断是否打开了中断。接下来就是通过bitpos USARTx-SR;判断下面寄存器SR的第五位。 综上所述 USART_GetITStatus判定的是事件标志和使能控制位这两个位同时为1返回值才为1 USART_GetFlagStatus函数
#define USART_FLAG_CTS ((uint16_t)0x0200)
#define USART_FLAG_LBD ((uint16_t)0x0100)
#define USART_FLAG_TXE ((uint16_t)0x0080)
#define USART_FLAG_TC ((uint16_t)0x0040)
#define USART_FLAG_RXNE ((uint16_t)0x0020)
#define USART_FLAG_IDLE ((uint16_t)0x0010)
#define USART_FLAG_ORE ((uint16_t)0x0008)
#define USART_FLAG_NE ((uint16_t)0x0004)
#define USART_FLAG_FE ((uint16_t)0x0002)
#define USART_FLAG_PE ((uint16_t)0x0001)FlagStatus USART_GetFlagStatus(USART_TypeDef* USARTx, uint16_t USART_FLAG)
{FlagStatus bitstatus RESET;/* Check the parameters */assert_param(IS_USART_ALL_PERIPH(USARTx));assert_param(IS_USART_FLAG(USART_FLAG));/* The CTS flag is not available for UART4 and UART5 */if (USART_FLAG USART_FLAG_CTS){assert_param(IS_USART_1236_PERIPH(USARTx));} if ((USARTx-SR USART_FLAG) ! (uint16_t)RESET){bitstatus SET;}else{bitstatus RESET;}return bitstatus;
}假设判定的是RXNE 标志位 #define USART_FLAG_RXNE ((uint16_t)0x0020) if ((USARTx-SR USART_FLAG) ! (uint16_t)RESET) { bitstatus SET; } 这不就是判定的SR寄存器的bit5-RXNE 标志位是不是1
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