看看库里的源码就知道了：
- /**
- * @brief Sets the selected data port bits.
- * @param GPIOx: where x can be (A..G) to select the GPIO peripheral.
- * @param GPIO_Pin: specifies the port bits to be written.
- * This parameter can be any combination of GPIO_Pin_x where x can be (0..15).
- * @retval None
- */
- void GPIO_SetBits(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin)
- {
- /* Check the parameters */
- assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
- assert_param(IS_GPIO_PIN(GPIO_Pin));
- GPIOx->BSRR = GPIO_Pin;
- }
- /**
- * @brief Clears the selected data port bits.
- * @param GPIOx: where x can be (A..G) to select the GPIO peripheral.
- * @param GPIO_Pin: specifies the port bits to be written.
- * This parameter can be any combination of GPIO_Pin_x where x can be (0..15).
- * @retval None
- */
- void GPIO_ResetBits(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin)
- {
- /* Check the parameters */
- assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
- assert_param(IS_GPIO_PIN(GPIO_Pin));
- GPIOx->BRR = GPIO_Pin;
- }
- /**
- * @brief Sets or clears the selected data port bit.
- * @param GPIOx: where x can be (A..G) to select the GPIO peripheral.
- * @param GPIO_Pin: specifies the port bit to be written.
- * This parameter can be one of GPIO_Pin_x where x can be (0..15).
- * @param BitVal: specifies the value to be written to the selected bit.
- * This parameter can be one of the BitAction enum values:
- * @arg Bit_RESET: to clear the port pin
- * @arg Bit_SET: to set the port pin
- * @retval None
- */
- void GPIO_WriteBit(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin, BitAction BitVal)
- {
- /* Check the parameters */
- assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
- assert_param(IS_GET_GPIO_PIN(GPIO_Pin));
- assert_param(IS_GPIO_BIT_ACTION(BitVal));
- if (BitVal != Bit_RESET)
- {
- GPIOx->BSRR = GPIO_Pin;
- }
- else
- {
- GPIOx->BRR = GPIO_Pin;
- }
- }
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