以前习惯写函数时,把初始化函数写成GPIO_Init()/UART_Init()的形式,这样一目了然,可是ST的库中有这样的定义
- void GPIO_Init(GPIO_TypeDef* GPIOx, GPIO_InitTypeDef* GPIO_InitStruct)
- {
- uint32_t currentmode = 0x00, currentpin = 0x00, pinpos = 0x00, pos = 0x00;
- uint32_t tmpreg = 0x00, pinmask = 0x00;
- /* Check the parameters */
- assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
- assert_param(IS_GPIO_MODE(GPIO_InitStruct->GPIO_Mode));
- assert_param(IS_GPIO_PIN(GPIO_InitStruct->GPIO_Pin));
-
- /*---------------------------- GPIO Mode Configuration -----------------------*/
- currentmode = ((uint32_t)GPIO_InitStruct->GPIO_Mode) & ((uint32_t)0x0F);
- if ((((uint32_t)GPIO_InitStruct->GPIO_Mode) & ((uint32_t)0x10)) != 0x00) //输出模式
- {
- /* Check the parameters */
- assert_param(IS_GPIO_SPEED(GPIO_InitStruct->GPIO_Speed));
- /* Output mode */
- currentmode |= (uint32_t)GPIO_InitStruct->GPIO_Speed;
- }
- /*---------------------------- GPIO CRL Configuration ------------------------*/ //低8位
- /* Configure the eight low port pins */
- if (((uint32_t)GPIO_InitStruct->GPIO_Pin & ((uint32_t)0x00FF)) != 0x00) //引脚有定义
- {
- tmpreg = GPIOx->CRL;
- for (pinpos = 0x00; pinpos < 0x08; pinpos++)
- {
- pos = ((uint32_t)0x01) << pinpos;
- /* Get the port pins position */
- currentpin = (GPIO_InitStruct->GPIO_Pin) & pos;
- if (currentpin == pos) //判断每一个脚
- {
- pos = pinpos << 2;
- /* Clear the corresponding low control register bits */
- pinmask = ((uint32_t)0x0F) << pos;
- tmpreg &= ~pinmask;
- /* Write the mode configuration in the corresponding bits */
- tmpreg |= (currentmode << pos);
- /* Reset the corresponding ODR bit */
- if (GPIO_InitStruct->GPIO_Mode == GPIO_Mode_IPD) // 端口置为高电平
- {
- GPIOx->BRR = (((uint32_t)0x01) << pinpos);
- }
- else
- {
- /* Set the corresponding ODR bit */
- if (GPIO_InitStruct->GPIO_Mode == GPIO_Mode_IPU) // 端口清0
- {
- GPIOx->BSRR = (((uint32_t)0x01) << pinpos);
- }
- }
- }
- }
- GPIOx->CRL = tmpreg;
- }
- /*---------------------------- GPIO CRH Configuration ------------------------*/
- /* Configure the eight high port pins */
- if (GPIO_InitStruct->GPIO_Pin > 0x00FF)
- {
- tmpreg = GPIOx->CRH;
- for (pinpos = 0x00; pinpos < 0x08; pinpos++)
- {
- pos = (((uint32_t)0x01) << (pinpos + 0x08));
- /* Get the port pins position */
- currentpin = ((GPIO_InitStruct->GPIO_Pin) & pos);
- if (currentpin == pos)
- {
- pos = pinpos << 2;
- /* Clear the corresponding high control register bits */
- pinmask = ((uint32_t)0x0F) << pos;
- tmpreg &= ~pinmask;
- /* Write the mode configuration in the corresponding bits */
- tmpreg |= (currentmode << pos);
- /* Reset the corresponding ODR bit */
- if (GPIO_InitStruct->GPIO_Mode == GPIO_Mode_IPD)
- {
- GPIOx->BRR = (((uint32_t)0x01) << (pinpos + 0x08));
- }
- /* Set the corresponding ODR bit */
- if (GPIO_InitStruct->GPIO_Mode == GPIO_Mode_IPU)
- {
- GPIOx->BSRR = (((uint32_t)0x01) << (pinpos + 0x08));
- }
- }
- }
- GPIOx->CRH = tmpreg;
- }
- }
所以,我们在写初始化函数的时候可以写成如下这样的形式
- void GPIO_config(void)
- {
- GPIO_InitTypeDef GPIO_InitStructure;
-
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB , ENABLE);//
- GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;//只初始化PC6
- GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;//通用外推输出
- GPIO_Init(GPIOC, &GPIO_InitStructure);//PC6控制IO
-
- }
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