stm32串口发送数据，比如发送“AT”把接收的数据作判断，如果是“OK”，发下一条指令“AR”，不是择返回“error”,采用HAL库编写

好的，针对你的问题，我可以给出一个使用HAL库编写的示例代码，它可以通过USART串口发送“AT”指令，并判断返回的数据是否为“OK”，如果是则发送“AR”指令，否则返回“error”信息，具体代码如下：

#include "stm32f1xx_hal.h"
#include <string.h>

#define USART_HANDLE huart1
#define USART_TIMEOUT 1000

UART_HandleTypeDef huart1;

void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART1_UART_Init(void);

int main(void)
{
    char buf[32];
    uint32_t start_time;
    uint8_t receive_byte;
    int i;

    /* Initialize HAL and system clock */
    HAL_Init();
    SystemClock_Config();

    /* Initialize GPIO and USART */
    MX_GPIO_Init();
    MX_USART1_UART_Init();

    /* Send "AT" command */
    HAL_UART_Transmit(&USART_HANDLE, (uint8_t*)"AT\r\n", strlen("AT\r\n"), USART_TIMEOUT);

    /* Wait for response */
    start_time = HAL_GetTick();
    i = 0;
    while (HAL_GetTick() - start_time < USART_TIMEOUT) {
        if (HAL_UART_Receive(&USART_HANDLE, &receive_byte, 1, USART_TIMEOUT) == HAL_OK) {
            buf[i++] = receive_byte;
            if (i >= 2 && buf[i-2] == 'O' && buf[i-1] == 'K') {
                /* Send "AR" command */
                HAL_UART_Transmit(&USART_HANDLE, (uint8_t*)"AR\r\n", strlen("AR\r\n"), USART_TIMEOUT);
                break;
            }
        }
    }

    /* If no response received, return error */
    if (i == 0 || (i < 2 || !(buf[i-2] == 'O' && buf[i-1] == 'K'))) {
        HAL_UART_Transmit(&USART_HANDLE, (uint8_t*)"error\r\n", strlen("error\r\n"), USART_TIMEOUT);
    }

    while (1);

    return 0;
}

void SystemClock_Config(void)
{
    RCC_OscInitTypeDef RCC_OscInitStruct;
    RCC_ClkInitTypeDef RCC_ClkInitStruct;

    /** 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.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
    RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
    RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
    RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
    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_DIV2;
    RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

    if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
    {
        Error_Handler();
    }
}

static void MX_USART1_UART_Init(void)
{
    huart1.Instance = USART1;
    huart1.Init.BaudRate = 115200;
    huart1.Init.WordLength = UART_WORDLENGTH_8B;
    huart1.Init.StopBits = UART_STOPBITS_1;
    huart1.Init.Parity = UART_PARITY_NONE;
    huart1.Init.Mode = UART_MODE_TX_RX;
    huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
    huart1.Init.OverSampling = UART_OVERSAMPLING_16;
    if (HAL_UART_Init(&huart1) != HAL_OK)
    {
        Error_Handler();
    }
}

static void MX_GPIO_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStruct;

    /* GPIO Ports Clock Enable */
    __HAL_RCC_GPIOA_CLK_ENABLE();

    /* Configure USART Tx and Rx pins */
    GPIO_InitStruct.Pin = GPIO_PIN_9 | GPIO_PIN_10;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
}

需要注意的是，使用HAL库编写的代码通常比使用标准库编写的代码更加简洁易读，同时也可以提高代码的可维护性和可移植性。但是，HAL库也会增加代码的体积和复杂度，因此在编写代码时需要根据实际需求进行选择。