nucleo-g474re和esp8266进行at指令的代码

以下是使用Nucleo-G474RE和ESP8266进行AT指令交互的示例代码：

#include "stm32g4xx_hal.h"
#include <stdio.h>
#include <string.h>

UART_HandleTypeDef huart2;

void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART2_UART_Init(void);

#define ESP8266_BUFFER_SIZE 1024

char esp8266Buffer[ESP8266_BUFFER_SIZE];
uint16_t esp8266BufferIndex = 0;

void esp8266SendCommand(char* command, uint32_t timeout);
void esp8266ClearBuffer(void);

int main(void)
{
  HAL_Init();
  SystemClock_Config();
  MX_GPIO_Init();
  MX_USART2_UART_Init();

  esp8266SendCommand("AT\r\n", 5000); // send AT command to ESP8266

  while (1)
  {
    if (esp8266BufferIndex > 0) {
      printf("%s", esp8266Buffer);
      esp8266ClearBuffer();
    }
  }
}

void esp8266SendCommand(char* command, uint32_t timeout)
{
  HAL_UART_Transmit(&huart2, (uint8_t*)command, strlen(command), timeout);

  HAL_UART_Receive_IT(&huart2, (uint8_t*)&esp8266Buffer[esp8266BufferIndex], 1);

  HAL_Delay(50);

  HAL_UART_Receive_IT(&huart2, (uint8_t*)&esp8266Buffer[esp8266BufferIndex], 1);
}

void esp8266ClearBuffer(void)
{
  memset(esp8266Buffer, 0, ESP8266_BUFFER_SIZE);
  esp8266BufferIndex = 0;
}

static void MX_USART2_UART_Init(void)
{
  huart2.Instance = USART2;
  huart2.Init.BaudRate = 115200;
  huart2.Init.WordLength = UART_WORDLENGTH_8B;
  huart2.Init.StopBits = UART_STOPBITS_1;
  huart2.Init.Parity = UART_PARITY_NONE;
  huart2.Init.Mode = UART_MODE_TX_RX;
  huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart2.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&huart2) != HAL_OK)
  {
    Error_Handler();
  }
}

static void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};

  __HAL_RCC_GPIOA_CLK_ENABLE();

  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, GPIO_PIN_SET);

  GPIO_InitStruct.Pin = GPIO_PIN_5;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
}

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
  if (esp8266Buffer[esp8266BufferIndex] == '\n') {
    esp8266Buffer[esp8266BufferIndex + 1] = '\0';
  } else {
    esp8266BufferIndex++;
  }

  HAL_UART_Receive_IT(&huart2, (uint8_t*)&esp8266Buffer[esp8266BufferIndex], 1);
}

void Error_Handler(void)
{
  __disable_irq();
  while (1)
  {
  }
}

void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  /** Supply configuration update enable
  */
  HAL_PWREx_ConfigSupply(PWR_LDO_SUPPLY);
  /** Configure the main internal regulator output voltage
  */
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI|RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLM = 2;
  RCC_OscInitStruct.PLL.PLLN = 50;
  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();
  }
}

该代码使用了HAL库，可以在STM32CubeIDE中创建一个基于NUCLEO-G474RE板的项目，并添加UART和GPIO库，然后将上述代码复制到main.c文件中即可。请注意，此代码仅发送AT指令并打印ESP8266的响应。如果您需要执行其他操作，请根据需要修改代码。