背景
在上一讲STM32 CubeMX 学习:搭建开发环境中,我们已经利用CubeMx搭建了可编译的工程。
今天就开始来介绍STM32 GPIO的有关知识,以及如何驱动它。
HOST-OS : Windows-10
STM32 Cube :v5.6
MCU : STM32F429
LIB : stm32cube_fw_f4_v1250
知识
在STM32中,GPIO有这些属性:输入、输出、复用功能;也可以设置速度,上下拉,推挽开漏等电器特性。
在Drivers/STM32F4xx_HAL_Driver/Inc/stm32f4xx_hal_gpio.h
中有关于 GPIO属性的 定义。
/**
* @brief GPIO Init structure definition
*/
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;
Pin : 指定的引脚号,右值表达式可以是 GPIO_PIN_0 ~ GPIO_PIN_15, GPIO_PIN_All 任意相或
Mode: 引脚的模式
- GPIO_MODE_INPUT 浮空输入模式:电平状态取决于GPIO外部的电平状态;若在GPIO外部的引脚悬空时,读取结果是不确定的。
- GPIO_MODE_OUTPUT_PP 推挽(Pull)输出模式(输出较大电流):推拉输出 既提高电路的负载能力,又提高开关速度。
- GPIO_MODE_OUTPUT_OD 开漏(Drain)输出模式(一般外接上拉电阻,如果外部不接上拉电阻只能输出低电平),可用于不同电压的系统之间的通信
- GPIO_MODE_AF_PP 复用推挽输出模式
- GPIO_MODE_OUTPUT_OD 复用开漏输出模式
- GPIO_MODE_ANALOG 复用模拟输入输出模式(ADC/DAC专用)
Pull:上/下拉模式
- GPIO_NOPULL 无(针对输出模式)
- GPIO_PULLUP 上拉输入(针对输入模式)
- GPIO_PULLDOWN 下拉输入(针对输入模式)
假设有一个GPIO口接到了 一个按键的一端,在此时:
- 如果按键的右端接正电源,那么就要 为 GPIO_PULLDOWN(下拉模式),因为这样才能使得按键按下去的时候,能把I / O脚拉高,否则按键的功能等于摆设。
- 同理,如果按键另一端接地,我们就要设置为GPIO_PULLUP(上拉模式)了。
Speed:IO口速率(I/O口驱动电路的响应速度)
当STM32的GPIO端口设置为输出模式时,有三种速度可以选择:2MHz、10MHz和50MHz,通过选择速度来选择不同的驱动电路,达到最佳的噪声控制和降低功耗的目的。(高频的驱动电路,噪声也高,当不需要高的输出频率时,请选用低频驱动电路,这样非常有利于提高系统的EMI性能。)
STM32F429的端口输出速率为括号内容:
- GPIO_SPEED_LOW; (2) 2MHz注意:
- GPIO_SPEED_MEDIUM; (25) 12.5MHz ~ 50MHz
- GPIO_SPEED_FAST; (50) 25MHz ~ 100 MHz
- GPIO_SPEED_HIGH; (100) 50MHz ~ 200MHz
Alternate:复用功能
本节课不讲。
CubeMx对GPIO的配置
注意,使用GPIO之前需要配置相应的时钟。当配置了引脚而显示了
⚠RCC
,证明需要RCC没有配置好。
1)在Pinout& Confiurgation
页的Pinout view
中,点击引脚,设置为GPIO_Input
或GPIO_Output
。
2)点击左栏的GPIO
,选择配置的引脚,在界面下方中部靠左的位置可以看到 类似PF4 Configuration
这一栏,根据引脚输入输出类型的不同,有这些选项
- GPIO output level(初始化输出电平)
- GPIO mode(模式)
- GPIO Pull-up/Pull-down(上下拉)
- Maximum output speed (输出响应速度)
- User Label(用户标签): 可以标记这个引脚是做什么用的,提高可读性。
3)点击右上角的GENERATE CODE
生成工程
4)使用外部的工具链编译工程,确保没有问题。
代码分析
/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file : main.c
* @brief : Main program body
******************************************************************************
* @attention
*
* <h2><center>© Copyright (c) 2020 STMicroelectronics.
* All rights reserved.</center></h2>
*
* This software component is licensed by ST under BSD 3-Clause license,
* the "License"; You may not use this file except in compliance with the
* License. You may obtain a copy of the License at:
* opensource.org/licenses/BSD-3-Clause
*
******************************************************************************
*/
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
/* USER CODE END Includes */
/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
/* USER CODE END PTD */
/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
/* USER CODE END PD */
/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */
/* USER CODE END PM */
/* Private variables ---------------------------------------------------------*/
SMBUS_HandleTypeDef hsmbus2;
/* USER CODE BEGIN PV */
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_I2C2_SMBUS_Init(void);
/* USER CODE BEGIN PFP */
/* USER CODE END PFP */
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
/* USER CODE END 0 */
/**
* @brief The application entry point.
* @retval int
*/
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_I2C2_SMBUS_Init();
/* USER CODE BEGIN 2 */
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
/**
* @brief System Clock Configuration
* @retval None
*/
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
/** Configure the main internal regulator output voltage
*/
__HAL_RCC_PWR_CLK_ENABLE();
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
/** Initializes the CPU, AHB and APB busses clocks
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
RCC_OscInitStruct.HSEState = RCC_HSE_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLM = 4;
RCC_OscInitStruct.PLL.PLLN = 168;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
RCC_OscInitStruct.PLL.PLLQ = 4;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
/** Initializes the CPU, AHB and APB busses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5) != HAL_OK)
{
Error_Handler();
}
}
/**
* @brief I2C2 Initialization Function
* @param None
* @retval None
*/
static void MX_I2C2_SMBUS_Init(void)
{
/* USER CODE BEGIN I2C2_Init 0 */
/* USER CODE END I2C2_Init 0 */
/* USER CODE BEGIN I2C2_Init 1 */
/* USER CODE END I2C2_Init 1 */
hsmbus2.Instance = I2C2;
hsmbus2.Init.AnalogFilter = SMBUS_ANALOGFILTER_ENABLE;
hsmbus2.Init.OwnAddress1 = 0;
hsmbus2.Init.AddressingMode = SMBUS_ADDRESSINGMODE_7BIT;
hsmbus2.Init.DualAddressMode = SMBUS_DUALADDRESS_DISABLE;
hsmbus2.Init.OwnAddress2 = 0;
hsmbus2.Init.GeneralCallMode = SMBUS_GENERALCALL_DISABLE;
hsmbus2.Init.NoStretchMode = SMBUS_NOSTRETCH_DISABLE;
hsmbus2.Init.PacketErrorCheckMode = SMBUS_PEC_DISABLE;
hsmbus2.Init.PeripheralMode = SMBUS_PERIPHERAL_MODE_SMBUS_SLAVE;
if (HAL_SMBUS_Init(&hsmbus2) != HAL_OK)
{
Error_Handler();
}
/** configuration Alert Mode
*/
if (HAL_SMBUS_EnableAlert_IT(&hsmbus2) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN I2C2_Init 2 */
/* USER CODE END I2C2_Init 2 */
}
/**
* @brief GPIO Initialization Function
* @param None
* @retval None
*/
static void MX_GPIO_Init(void)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOF_CLK_ENABLE();
__HAL_RCC_GPIOH_CLK_ENABLE();
__HAL_RCC_GPIOB_CLK_ENABLE();
/*Configure GPIO pin Output Level */
HAL_GPIO_WritePin(GPIOF, GPIO_PIN_5, GPIO_PIN_RESET);
/*Configure GPIO pin : PF0 */
GPIO_InitStruct.Pin = GPIO_PIN_0;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_PULLUP;
HAL_GPIO_Init(GPIOF, &GPIO_InitStruct);
/*Configure GPIO pin : PF4 */
GPIO_InitStruct.Pin = GPIO_PIN_4;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_PULLDOWN;
HAL_GPIO_Init(GPIOF, &GPIO_InitStruct);
/*Configure GPIO pin : PF5 */
GPIO_InitStruct.Pin = GPIO_PIN_5;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_OD;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_MEDIUM;
HAL_GPIO_Init(GPIOF, &GPIO_InitStruct);
}
/* USER CODE BEGIN 4 */
/* USER CODE END 4 */
/**
* @brief This function is executed in case of error occurrence.
* @retval None
*/
void Error_Handler(void)
{
/* USER CODE BEGIN Error_Handler_Debug */
/* User can add his own implementation to report the HAL error return state */
/* USER CODE END Error_Handler_Debug */
}
#ifdef USE_FULL_ASSERT
/**
* @brief Reports the name of the source file and the source line number
* where the assert_param error has occurred.
* @param file: pointer to the source file name
* @param line: assert_param error line source number
* @retval None
*/
void assert_failed(uint8_t *file, uint32_t line)
{
/* USER CODE BEGIN 6 */
/* User can add his own implementation to report the file name and line number,
tex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
/* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/