几种在ARM MCU上控制流水灯的方法

对于初学者，在ARM单片机上控制流水灯的亮灭是必经之路。控制流水灯的亮灭有很多方法，比如8个LED，可以控制8灯同时亮、灭；可以控制8灯依次亮、灭；可以控制8灯依次亮、灭，然后反方向再依次亮、灭；可以控制8灯依次点亮全部、然后依次熄灭全部；

1、建立.ioc工程

实例使用的开发板是ST公司的NUCLEO-G474RE，使用的MCU型号STM32G474RET6，淘宝上有卖。

实例使用的配套扩展板：

实例所创建的工程简介：使用MCU的PB0~PB7依次连接扩展板的LED0~LED7，外部时钟源24MHz，系统时钟SYSCLK配置为170MHz，GPIO output lecel = High，GPIO mode = PP，GPIO Pull up/Pull down = Pull_up。工程名称：ex_led_ch2.ioc。其它，略。

2、控制8灯同时亮、灭

当熟悉了HAL_GPIO_WritePin()函数的定义之后，就可以修改ex_led_ch2中的代码，用HAL_GPIO_WritePin()函数来实现对发光二极管亮灭的控制。主要通过修改main.c文件中while(1)循环的代码来实现。

修改后的代码如下：

/* 8个灯同时亮灭 */
HAL_GPIO_WritePin(LED0_GPIO_Port,LED0_Pin,GPIO_PIN_RESET);
HAL_GPIO_WritePin(LED1_GPIO_Port,LED1_Pin,GPIO_PIN_RESET);
HAL_GPIO_WritePin(LED2_GPIO_Port,LED2_Pin,GPIO_PIN_RESET);
HAL_GPIO_WritePin(LED3_GPIO_Port,LED3_Pin,GPIO_PIN_RESET);
HAL_GPIO_WritePin(LED4_GPIO_Port,LED4_Pin,GPIO_PIN_RESET);
HAL_GPIO_WritePin(LED5_GPIO_Port,LED5_Pin,GPIO_PIN_RESET);
HAL_GPIO_WritePin(LED6_GPIO_Port,LED6_Pin,GPIO_PIN_RESET);
HAL_GPIO_WritePin(LED7_GPIO_Port,LED7_Pin,GPIO_PIN_RESET);
HAL_Delay(500);
HAL_GPIO_WritePin(LED0_GPI0_Port,LED0_Pin,GPIO_PIN_SET);
HAL_GPIO_WritePin(LED1_GPIO_Port,LED1_Pin,GPIO_PIN_SET);
HAL_GPIO_WritePin(LED2_GPIO_Port,LED2_Pin,GPIO_PIN_SET);
HAL_GPIO_WritePin(LED3_GPIO_Port,LED3_Pin,GPIO_PIN_SET);
HAL_GPIO_WritePin(LED4_GPI0_Port,LED4_Pin,GPIO_PIN_SET);
HAL_GPIO_WritePin(LED5_GPIO_Port,LED5_Pin,GPIO_PIN_SET);
HAL_GPIO_WritePin(LED6_GPI0_Port,LED6_Pin,GPIO_PIN_SET);
HAL_GPIO_WritePin(LED7_GPI0_Port,LED7_Pin,GPIO_PIN_SET);
HAL_Delay(500);

当然也可以用HAL_GPIO_TogglePin()函数来实现。

/* 8个灯同时亮灭 */
HAL_GPIO_TogglePin(LED0_GPIO_Port,LED0_Pin);
HAL_GPIO_TogglePin(LED1_GPIO_Port,LED1_Pin);
HAL_GPIO_TogglePin(LED2_GPIO_Port,LED2_Pin);
HAL_GPIO_TogglePin(LED3_GPIO_Port,LED3_Pin);
HAL_GPIO_TogglePin(LED4_GPIO_Port,LED4_Pin);
HAL_GPIO_TogglePin(LED5_GPIO_Port,LED5_Pin);
HAL_GPIO_TogglePin(LED6_GPIO_Port,LED6_Pin);
HAL_GPIO_TogglePin(LED7_GPIO_Port,LED7_Pin);
HAL_Delay(500);

编译、下载后，会发现8个发光二极管同时闪烁，并且闪烁周期与使用HAL_GPIO_Tog-lePin()函数时完全相同。

3、控制8灯依次亮、灭

有多种方式可以实现让8个发光二极管按顾序依次闪烁。

假如还用HAL_GPIO_WritePin()实现对I/O输出状态的控制。要想实现上述功能，需顺次改变传递给HAL_GPIO_WritePin(GPIOx,GPIO_Pin,PinState)函数的GPIO_Pin(引脚号)参数就可以了。可以定义一个变量，譬如led_num作为引脚号，由于只需控制8个I/O，所以led_num只要8位就够了，于是可将led_num定义为8位无符号数(uint8_t)。当然，要实现顺次点亮发光二极管，变量led_num的8位中，在某一时刻只能有1位为1，以控其中一个I/O；到下一时刻，让该位移位，就可控制下一个I/O。led_num的初值可以为0x01。

定义好led_num以后，可以利用一个循环次数为8的for语句，将led_num传递给HAL_GPIO _WritePin(GPIOx,GPIO_Pin,PinState)函数的GPIO_Pin参数，调用延时函数，随后改变led_num的值(移位)。当然，在两次调用WritePin函数时，还要配合修改PinState参数，这样，就可以实现让灯依次闪烁的功能。

根据以上分析，修改while(1)循环中的代码如下：

uint8_t led_num = 0x01;
for(uint8_t i=0;i<8;i++)
{
HAL_GPIO_WritePin(GPIOB,led_num,GPIO_PIN_RESET)
HAL_Delay(500);	//延时500 ms
HAL_GPIO_WritePin(GPIOB,led_num,GPIO_PIN_SET)
HAL_Delay(500);	//延时500 ms
led_num <<= 1;	//通过移位，改变led_num的值
}

4、控制8灯依次一个方向亮灭，然后再反方向依次亮灭

修改代码实现另一种闪烁效果:当第8个灯闪烁后,再反方向（从8到1）控制灯的闪烁。

uint8_t led_num = 0x01;
uint8_t led_num_reverse = 0x80;
for(uint8_t i=0;i < 8;i++)
{HAL_GPIO_WritePin(GPIOB,led_num,GPIO_PIN_RESET);HAL_Delay(500);HAL_GPIO_WritePin(GPIOB,led_num,GPIO_PIN_SET);HAL_Delay(500);led_num <<= 1;
}
for(uint8_t i=0;i < 8;i++)
{HAL_GPIO_WritePin(GPIOB,led_num_reverse,GPIO_PIN_RESET);HAL_Delay(500);HAL_GPIO_WritePin(GPIOB,led_num_reverse,GPIO_PIN_SET);HAL_Delay(500);led_num_re >>= 1;
}

5、控制8灯依次点亮全部、然后依次熄灭全部

进一步修改代码，实现让8个发光二极管依次点亮再依次熄灭的效果。

使用HAL_GPIO_TogglePin()函数，实现对I/O输出状态的控制。HAL_GPIO_TogglePin(GPIO_TypeDef *GPIOx,uint16_t GPIO_Pin)函数有两个参数：一个是端口，由于使用的是GPIOB端口，所以可以不用改变；另一个是引脚号，可以尝试在改变引脚号上着手。

还是用变量led_num作为引脚号，并将其初值设为0x01。然后依然用一个循环次数为8的for语句，将led_num传递给HAL_GPIO_TogglePin()函数的GPIO_Pin参数，随后改变led_num的值(移位)，再调用延时函数。这样就可以实现让发光二极管依次点亮再依次熄灭的流水灯效果。

修改while(1)循环中的代码：

uint8_t led_num = 0x01;
for(uint8_t i=0;i < 8;i++)
{HAL_GPIO_TogglePin(GPIOB,led_num);led_num <<= 1;HAL_Delay(500);
}

6、main.c源码

/* USER CODE BEGIN Header */
/********************************************************************************* @file           : main.c* @brief          : Main program body******************************************************************************* @attention** Copyright (c) 2024 STMicroelectronics.* All rights reserved.** This software is licensed under terms that can be found in the LICENSE file* in the root directory of this software component.* If no LICENSE file comes with this software, it is provided AS-IS.********************************************************************************/
/* 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 ---------------------------------------------------------*//* USER CODE BEGIN PV *//* USER CODE END PV *//* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_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();/* USER CODE BEGIN 2 *//* USER CODE END 2 *//* Infinite loop *//* USER CODE BEGIN WHILE */while (1){/* USER CODE END WHILE *//* USER CODE BEGIN 3 *//* 8个灯同时亮灭 *//* HAL_GPIO_TogglePin(LED0_GPIO_Port,LED0_Pin);HAL_GPIO_TogglePin(LED1_GPIO_Port,LED1_Pin);HAL_GPIO_TogglePin(LED2_GPIO_Port,LED2_Pin);HAL_GPIO_TogglePin(LED3_GPIO_Port,LED3_Pin);HAL_GPIO_TogglePin(LED4_GPIO_Port,LED4_Pin);HAL_GPIO_TogglePin(LED5_GPIO_Port,LED5_Pin);HAL_GPIO_TogglePin(LED6_GPIO_Port,LED6_Pin);HAL_GPIO_TogglePin(LED7_GPIO_Port,LED7_Pin);HAL_Delay(1000); *//* 8个灯同时亮灭 *//* HAL_GPIO_WritePin(LED0_GPIO_Port,LED0_Pin,GPIO_PIN_RESET);HAL_GPIO_WritePin(LED1_GPIO_Port,LED1_Pin,GPIO_PIN_RESET);HAL_GPIO_WritePin(LED2_GPIO_Port,LED2_Pin,GPIO_PIN_RESET);HAL_GPIO_WritePin(LED3_GPIO_Port,LED3_Pin,GPIO_PIN_RESET);HAL_GPIO_WritePin(LED4_GPIO_Port,LED4_Pin,GPIO_PIN_RESET);HAL_GPIO_WritePin(LED5_GPIO_Port,LED5_Pin,GPIO_PIN_RESET);HAL_GPIO_WritePin(LED6_GPIO_Port,LED6_Pin,GPIO_PIN_RESET);HAL_GPIO_WritePin(LED7_GPIO_Port,LED7_Pin,GPIO_PIN_RESET);HAL_Delay(500);HAL_GPIO_WritePin(LED0_GPI0_Port,LED0_Pin,GPIO_PIN_SET);HAL_GPIO_WritePin(LED1_GPIO_Port,LED1_Pin,GPIO_PIN_SET);HAL_GPIO_WritePin(LED2_GPIO_Port,LED2_Pin,GPIO_PIN_SET);HAL_GPIO_WritePin(LED3_GPIO_Port,LED3_Pin,GPIO_PIN_SET);HAL_GPIO_WritePin(LED4_GPI0_Port,LED4_Pin,GPIO_PIN_SET);HAL_GPIO_WritePin(LED5_GPIO_Port,LED5_Pin,GPIO_PIN_SET);HAL_GPIO_WritePin(LED6_GPI0_Port,LED6_Pin,GPIO_PIN_SET);HAL_GPIO_WritePin(LED7_GPI0_Port,LED7_Pin,GPIO_PIN_SET);HAL_Delay(500); *//* 8个灯依次亮灭 *//* uint8_t led_num = 0x01;for(uint8_t i=0;i<8;i++){HAL_GPIO_WritePin(GPIOB,led_num,GPIO_PIN_RESET);HAL_Delay(500);	//延时500msHAL_GPIO_WritePin(GPIOB,led_num,GPIO_PIN_SET);HAL_Delay(500);	//延时500msled_num <<= 1;		//通过移位，改变led_num的值} *//* 循环左移，当第8个灯时，反方向右移，以类类推 *//* uint8_t led_num = 0x01;uint8_t led_num_reverse = 0x80;for(uint8_t i=0;i < 8;i++){HAL_GPIO_WritePin(GPIOB,led_num,GPIO_PIN_RESET);HAL_Delay(500);HAL_GPIO_WritePin(GPIOB,led_num,GPIO_PIN_SET);HAL_Delay(500);led_num <<= 1;}for(uint8_t i=0;i < 8;i++){HAL_GPIO_WritePin(GPIOB,led_num_reverse,GPIO_PIN_RESET);HAL_Delay(500);HAL_GPIO_WritePin(GPIOB,led_num_reverse,GPIO_PIN_SET);HAL_Delay(500);led_num_reverse >>= 1;}	*//* 8个LED依次点亮再依次熄灭 */uint8_t led_num = 0x01;for(uint8_t i=0;i < 8;i++){HAL_GPIO_TogglePin(GPIOB,led_num);led_num <<= 1;HAL_Delay(500);}}/* 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_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1_BOOST);/** Initializes the RCC Oscillators according to the specified parameters* in the RCC_OscInitTypeDef structure.*/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 = RCC_PLLM_DIV6;RCC_OscInitStruct.PLL.PLLN = 85;RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;RCC_OscInitStruct.PLL.PLLQ = RCC_PLLQ_DIV2;RCC_OscInitStruct.PLL.PLLR = RCC_PLLR_DIV2;if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK){Error_Handler();}/** Initializes the CPU, AHB and APB buses 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_DIV1;RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_4) != HAL_OK){Error_Handler();}
}/*** @brief GPIO Initialization Function* @param None* @retval None*/
static void MX_GPIO_Init(void)
{GPIO_InitTypeDef GPIO_InitStruct = {0};
/* USER CODE BEGIN MX_GPIO_Init_1 */
/* USER CODE END MX_GPIO_Init_1 *//* GPIO Ports Clock Enable */__HAL_RCC_GPIOF_CLK_ENABLE();__HAL_RCC_GPIOB_CLK_ENABLE();__HAL_RCC_GPIOA_CLK_ENABLE();/*Configure GPIO pin Output Level */HAL_GPIO_WritePin(GPIOB, LED0_Pin|LED1_Pin|LED2_Pin|LED3_Pin|LED4_Pin|LED5_Pin|LED6_Pin|LED7_Pin, GPIO_PIN_SET);/*Configure GPIO pins : LED0_Pin LED1_Pin LED2_Pin LED4_PinLED5_Pin LED6_Pin LED7_Pin */GPIO_InitStruct.Pin = LED0_Pin|LED1_Pin|LED2_Pin|LED4_Pin|LED5_Pin|LED6_Pin|LED7_Pin;GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;GPIO_InitStruct.Pull = GPIO_PULLUP;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);/*Configure GPIO pin : LED3_Pin */GPIO_InitStruct.Pin = LED3_Pin;GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_OD;GPIO_InitStruct.Pull = GPIO_PULLUP;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;HAL_GPIO_Init(LED3_GPIO_Port, &GPIO_InitStruct);/* USER CODE BEGIN MX_GPIO_Init_2 */
/* USER CODE END MX_GPIO_Init_2 */
}/* 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 */__disable_irq();while (1){}/* 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,ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) *//* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */