今天介HAL庫操作普通IO口，就是輸入/輸出。
如果用CubeMX配置io工程，打開以後可以看到如下代碼：
GPIO_InitTypeDef GPIO_Initure;
__HAL_RCC_GPIOB_CLK_ENABLE(); // 根據名字，這是使能B端口
GPIO_Initure.Pin=GPIO_PIN_0; // 0口
GPIO_Initure.Mode=GPIO_MODE_OUTPUT_PP; // 推輓輸出
GPIO_Initure.Pull=GPIO_PULLUP; // 上拉
GPIO_Initure.Speed=GPIO_SPEED_HIGH; // 高速
HAL_GPIO_Init(GPIOB,&GPIO_Initure); // 調用初始化函數
HAL_GPIO_WritePin(GPIOB,GPIO_PIN_0,GPIO_PIN_SET); // 初始化電平看到代碼的時候，如果想深入瞭解一定要深入的仔細分析，看看到底是怎麼調用的，操作了那些寄存器（不需要自己操作，但是要了解），用一個詞來概括，抽絲剝繭。首先定義了一個 GPIO_InitTypeDef 類型的結構體，從名字可以看出是IO口初始化的類型配置，然後使能B端口，再然後配置剛才定義的結構體，把各種功能賦給各個成員變量。我們可以看一下這個結構體怎麼定義的，，代碼如下：
typedef struct
{
uint32_t Pin; /*!< Specifies the GPIO pins to be configured.
This parameter can be any value of @ref GPIO_pins_define */
uint32_t Mode; /*!< Specifies the operating mode for the selected pins.
This parameter can be a value of @ref GPIO_mode_define */
uint32_t Pull; /*!< Specifies the Pull-up or Pull-Down activation for the selected pins.
This parameter can be a value of @ref GPIO_pull_define */
uint32_t Speed; /*!< Specifies the speed for the selected pins.
This parameter can be a value of @ref GPIO_speed_define */
uint32_t Alternate; /*!< Peripheral to be connected to the selected pins.
This parameter can be a value of @ref GPIO_Alternate_function_selection */
}GPIO_InitTypeDef;
這個結構體裏面每一個元素都要仔細的看一下，Pin：指定配置那個腳，那參數怎麼看呢？看英文註釋，他説：這個參數是GPIO_pins_define的任何一個，這個又是什麼呢？進去看看？會發現這不是變量，找不到他，那沒辦法，既註釋中有他，那麼我們肯定是可以找到的，那就整個工程搜索一下，還真的搜到了，如下：
/** @defgroup GPIO_pins_define GPIO pins define
* @{
*/
#define GPIO_PIN_0 ((uint16_t)0x0001) /* Pin 0 selected */
#define GPIO_PIN_1 ((uint16_t)0x0002) /* Pin 1 selected */
#define GPIO_PIN_2 ((uint16_t)0x0004) /* Pin 2 selected */
#define GPIO_PIN_3 ((uint16_t)0x0008) /* Pin 3 selected */
#define GPIO_PIN_4 ((uint16_t)0x0010) /* Pin 4 selected */
#define GPIO_PIN_5 ((uint16_t)0x0020) /* Pin 5 selected */
#define GPIO_PIN_6 ((uint16_t)0x0040) /* Pin 6 selected */
#define GPIO_PIN_7 ((uint16_t)0x0080) /* Pin 7 selected */
#define GPIO_PIN_8 ((uint16_t)0x0100) /* Pin 8 selected */
#define GPIO_PIN_9 ((uint16_t)0x0200) /* Pin 9 selected */
#define GPIO_PIN_10 ((uint16_t)0x0400) /* Pin 10 selected */
#define GPIO_PIN_11 ((uint16_t)0x0800) /* Pin 11 selected */
#define GPIO_PIN_12 ((uint16_t)0x1000) /* Pin 12 selected */
#define GPIO_PIN_13 ((uint16_t)0x2000) /* Pin 13 selected */
#define GPIO_PIN_14 ((uint16_t)0x4000) /* Pin 14 selected */
#define GPIO_PIN_15 ((uint16_t)0x8000) /* Pin 15 selected */
#define GPIO_PIN_All ((uint16_t)0xFFFF) /* All pins selected */
#define GPIO_PIN_MASK ((uint32_t)0x0000FFFF) /* PIN mask for assert test */
其實意思就是，結構體中的Pin變量可以是這些宏定義中的任何一個，從命名來説也就是0-15哪些腳。繼續看，Mode：指定那個腳的模式，這個參數可以是 GPIO_mode_define 中的任何一個，找到他看看，如下：
/** @defgroup GPIO_mode_define GPIO mode define
* @brief GPIO Configuration Mode
* Elements values convention: 0xX0yz00YZ
* - X : GPIO mode or EXTI Mode
* - y : External IT or Event trigger detection
* - z : IO configuration on External IT or Event
* - Y : Output type (Push Pull or Open Drain)
* - Z : IO Direction mode (Input, Output, Alternate or Analog)
* @{
*/
#define GPIO_MODE_INPUT ((uint32_t)0x00000000) /*!< Input Floating Mode */
#define GPIO_MODE_OUTPUT_PP ((uint32_t)0x00000001) /*!< Output Push Pull Mode */
#define GPIO_MODE_OUTPUT_OD ((uint32_t)0x00000011) /*!< Output Open Drain Mode */
#define GPIO_MODE_AF_PP ((uint32_t)0x00000002) /*!< Alternate Function Push Pull Mode */
#define GPIO_MODE_AF_OD ((uint32_t)0x00000012) /*!< Alternate Function Open Drain Mode */
#define GPIO_MODE_ANALOG ((uint32_t)0x00000003) /*!< Analog Mode */
#define GPIO_MODE_IT_RISING ((uint32_t)0x10110000) /*!< External Interrupt Mode with Rising edge trigger detection */
#define GPIO_MODE_IT_FALLING ((uint32_t)0x10210000) /*!< External Interrupt Mode with Falling edge trigger detection */
#define GPIO_MODE_IT_RISING_FALLING ((uint32_t)0x10310000) /*!< External Interrupt Mode with Rising/Falling edge trigger detection */
#define GPIO_MODE_EVT_RISING ((uint32_t)0x10120000) /*!< External Event Mode with Rising edge trigger detection */
#define GPIO_MODE_EVT_FALLING ((uint32_t)0x10220000) /*!< External Event Mode with Falling edge trigger detection */
#define GPIO_MODE_EVT_RISING_FALLING ((uint32_t)0x10320000) /*!< External Event Mode with Rising/Falling edge trigger detection */上面就是IO口的各種功能配置，依次是：輸入、推輓輸出、開漏輸出等等。同理，可以可以找到Pull、Speed等可以賦什麼值。到此這個結構體就“充滿”了，配置好了，我們的告訴系統啊，好接下來調用 HAL_GPIO_Init(GPIOB,&GPIO_Initure); 就是把剛才配製好的結構體扔到這個叫做IO口初始化的函數中。這個函數有兩個參數，第一個是B就是那個端口，第二個是我們配置的結構體，其實就是：B端口的0號腳，這樣的功能。這個函數太長了，説關鍵的部分，該函數會把我們的引腳的功能逐個抽離出來，然後配置相應的寄存器，就實現了這個腳的配置，代碼如下：
void HAL_GPIO_Init(GPIO_TypeDef *GPIOx, GPIO_InitTypeDef *GPIO_Init)
{
uint32_t position;
uint32_t ioposition = 0x00;
uint32_t iocurrent = 0x00;
uint32_t temp = 0x00;
/* Check the parameters 這裏是檢查我們的配置的參數是否正確 */
assert_param(IS_GPIO_ALL_INSTANCE(GPIOx));
assert_param(IS_GPIO_PIN(GPIO_Init->Pin));
assert_param(IS_GPIO_MODE(GPIO_Init->Mode));
assert_param(IS_GPIO_PULL(GPIO_Init->Pull));
/* Configure the port pins */
for(position = 0; position < GPIO_NUMBER; position++)
{
/* Get the IO position */
ioposition = ((uint32_t)0x01) << position;
/* Get the current IO position */
iocurrent = (uint32_t)(GPIO_Init->Pin) & ioposition;
if(iocurrent == ioposition)
{
/*--------------------- GPIO Mode Configuration ------------------------*/
/* In case of Alternate function mode selection */
if((GPIO_Init->Mode == GPIO_MODE_AF_PP) || (GPIO_Init->Mode == GPIO_MODE_AF_OD))
{
/* Check the Alternate function parameter */
assert_param(IS_GPIO_AF(GPIO_Init->Alternate));
/* Configure Alternate function mapped with the current IO */
temp = GPIOx->AFR[position >> 3];
temp &= ~((uint32_t)0xF << ((uint32_t)(position & (uint32_t)0x07) * 4)) ;
temp |= ((uint32_t)(GPIO_Init->Alternate) << (((uint32_t)position & (uint32_t)0x07) * 4));
GPIOx->AFR[position >> 3] = temp;
}
/* Configure IO Direction mode (Input, Output, Alternate or Analog) */
temp = GPIOx->MODER;
temp &= ~(GPIO_MODER_MODER0 << (position * 2));
temp |= ((GPIO_Init->Mode & GPIO_MODE) << (position * 2));
GPIOx->MODER = temp;
/* In case of Output or Alternate function mode selection */
if((GPIO_Init->Mode == GPIO_MODE_OUTPUT_PP) || (GPIO_Init->Mode == GPIO_MODE_AF_PP) ||
(GPIO_Init->Mode == GPIO_MODE_OUTPUT_OD) || (GPIO_Init->Mode == GPIO_MODE_AF_OD))
{
/* Check the Speed parameter */
assert_param(IS_GPIO_SPEED(GPIO_Init->Speed));
/* Configure the IO Speed */
temp = GPIOx->OSPEEDR;
temp &= ~(GPIO_OSPEEDER_OSPEEDR0 << (position * 2));
temp |= (GPIO_Init->Speed << (position * 2));
GPIOx->OSPEEDR = temp;
/* Configure the IO Output Type */
temp = GPIOx->OTYPER;
temp &= ~(GPIO_OTYPER_OT_0 << position) ;
temp |= (((GPIO_Init->Mode & GPIO_OUTPUT_TYPE) >> 4) << position);
GPIOx->OTYPER = temp;
}
/* Activate the Pull-up or Pull down resistor for the current IO */
temp = GPIOx->PUPDR;
temp &= ~(GPIO_PUPDR_PUPDR0 << (position * 2));
temp |= ((GPIO_Init->Pull) << (position * 2));
GPIOx->PUPDR = temp;
/*--------------------- EXTI Mode Configuration ------------------------*/
/* Configure the External Interrupt or event for the current IO */
if((GPIO_Init->Mode & EXTI_MODE) == EXTI_MODE)
{
/* Enable SYSCFG Clock */
__HAL_RCC_SYSCFG_CLK_ENABLE();
temp = SYSCFG->EXTICR[position >> 2];
temp &= ~(((uint32_t)0x0F) << (4 * (position & 0x03)));
temp |= ((uint32_t)(GPIO_GET_INDEX(GPIOx)) << (4 * (position & 0x03)));
SYSCFG->EXTICR[position >> 2] = temp;
/* Clear EXTI line configuration */
temp = EXTI->IMR;
temp &= ~((uint32_t)iocurrent);
if((GPIO_Init->Mode & GPIO_MODE_IT) == GPIO_MODE_IT)
{
temp |= iocurrent;
}
EXTI->IMR = temp;
temp = EXTI->EMR;
temp &= ~((uint32_t)iocurrent);
if((GPIO_Init->Mode & GPIO_MODE_EVT) == GPIO_MODE_EVT)
{
temp |= iocurrent;
}
EXTI->EMR = temp;
/* Clear Rising Falling edge configuration */
temp = EXTI->RTSR;
temp &= ~((uint32_t)iocurrent);
if((GPIO_Init->Mode & RISING_EDGE) == RISING_EDGE)
{
temp |= iocurrent;
}
EXTI->RTSR = temp;
temp = EXTI->FTSR;
temp &= ~((uint32_t)iocurrent);
if((GPIO_Init->Mode & FALLING_EDGE) == FALLING_EDGE)
{
temp |= iocurrent;
}
EXTI->FTSR = temp;
}
}
}
}View Code
回過頭來，再看一下開啓GPIOB時鐘，__HAL_RCC_GPIOB_CLK_ENABLE(); 他是一個很大的宏，把和這個宏有關的都貼上一起分析：
#define __HAL_RCC_GPIOB_CLK_ENABLE() do { \
__IO uint32_t tmpreg = 0x00; \
SET_BIT(RCC->AHB1ENR, RCC_AHB1ENR_GPIOBEN);\
/* Delay after an RCC peripheral clock enabling */ \
tmpreg = READ_BIT(RCC->AHB1ENR, RCC_AHB1ENR_GPIOBEN);\
UNUSED(tmpreg); \
} while(0)
#define SET_BIT(REG, BIT) ((REG) |= (BIT))
#define RCC_AHB1ENR_GPIOBEN ((uint32_t)0x00000002)
#define READ_BIT(REG, BIT) ((REG) & (BIT))
#define UNUSED(x) ((void)(x)) // 避免警告——百度這個宏，簡單一點看，把當作一個函數看一下，執行一次do裏面的，把寄存器 AHB1ENR 1位置1，就是使能GPIOB。
總結一下IO是使用，想配置一個腳作為普通口用，就要定義一個配置結構體，初始化這個腳所在的口的時鐘，然後“填滿”它，在把他扔到初始化函數中，到此，就配置好了一個普通的IO口作為輸入輸出。
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