复位所有IO口帮忙解释一下为什么这样写？

grant · 发表于 2013-6-3 16:25:00

//系统进入待机模式
void Sys_Enter_Standby(void)
{
RCC_APB2PeriphResetCmd(0X01FC,DISABLE); //复位所有IO口
Sys_Standby();
}

/**
* @brief Forces or releases High Speed APB (APB2) peripheral reset.
* @param RCC_APB2Periph: specifies the APB2 peripheral to reset.
*   This parameter can be any combination of the following values:
*     @arg RCC_APB2Periph_AFIO, RCC_APB2Periph_GPIOA, RCC_APB2Periph_GPIOB,
*          RCC_APB2Periph_GPIOC, RCC_APB2Periph_GPIOD, RCC_APB2Periph_GPIOE,
*          RCC_APB2Periph_GPIOF, RCC_APB2Periph_GPIOG, RCC_APB2Periph_ADC1,
*          RCC_APB2Periph_ADC2, RCC_APB2Periph_TIM1, RCC_APB2Periph_SPI1,
*          RCC_APB2Periph_TIM8, RCC_APB2Periph_USART1, RCC_APB2Periph_ADC3,
*          RCC_APB2Periph_TIM15, RCC_APB2Periph_TIM16, RCC_APB2Periph_TIM17,
*          RCC_APB2Periph_TIM9, RCC_APB2Periph_TIM10, RCC_APB2Periph_TIM11
* @param NewState: new state of the specified peripheral reset.
*   This parameter can be: ENABLE or DISABLE.
* @retval None
*/
void RCC_APB2PeriphResetCmd(uint32_t RCC_APB2Periph, FunctionalState NewState)
{
/* Check the parameters */
assert_param(IS_RCC_APB2_PERIPH(RCC_APB2Periph));
assert_param(IS_FUNCTIONAL_STATE(NewState));
if (NewState != DISABLE)
{
    RCC->APB2RSTR |= RCC_APB2Periph;
}
else
{
    RCC->APB2RSTR &= ~RCC_APB2Periph;
}
}