stm32h7 使用libmodbus错误码-1 求问

发布于 2021-08-04 22:07:00 浏览：1588 订阅该版

板子是银杏的stm32h750 icore4t,前面移植freemodbus，不是报错误3就是错误4，所以来用Libmodbus，但是还是有问题

因为我没找到RS485的控制引脚，所以就用的232，主程序代码如下：
```c
//#define RS485_RE GET_PIN(G, 8)
//#define HAVE_DECL_TIOCM_RTS 0

static void test_thread(void *param)
{
   //#define RS485_RE GET_PIN(G, 8)
//#define HAVE_DECL_TIOCM_RTS 0

static void test_thread(void *param)
{
    uint16_t tab_reg[64] = {0};
    modbus_t *ctx = RT_NULL;
    ctx = modbus_new_rtu("/dev/uart1", 115200, 'N', 8, 1);
    modbus_rtu_set_serial_mode(ctx, MODBUS_RTU_RS232);
   // modbus_rtu_set_rts(ctx, RS485_RE, MODBUS_RTU_RTS_UP);
    modbus_set_slave(ctx, 1);
    modbus_connect(ctx);
    modbus_set_response_timeout(ctx, 0, 1000000);
    int num = 0;
    while (1)
    {
        memset(tab_reg, 0, 64 * 2);
        int regs = modbus_read_registers(ctx, 0, 10, tab_reg);
        printf("-------------------------------------------\n");
        printf("[%4d][read num = %d]", num, regs);
        num++;
        int i;
        for (i = 0; i < 10; i++)
        {
            printf("<%#x>", tab_reg[i]);
        }
        printf("\n");
        printf("-------------------------------------------\n");
        rt_thread_mdelay(5000);
    }
    //7-关闭modbus端口
    modbus_close(ctx);

//8-释放modbus资源
    modbus_free(ctx);
}

int rtu_test_init(void)
{
   // rt_pin_mode(RS485_RE, PIN_MODE_OUTPUT);
    rt_thread_t tid;
    tid = rt_thread_create("test",
                           test_thread, RT_NULL,
                           2048,
                           12, 10);
    if (tid != RT_NULL)
        rt_thread_startup(tid);
    return RT_EOK;
}
INIT_APP_EXPORT(rtu_test_init);
}
```

串口设置如下：
```c
if(huart->Instance==USART1)
  {
  /* USER CODE BEGIN USART1_MspInit 0 */

/* USER CODE END USART1_MspInit 0 */
  /** Initializes the peripherals clock
  */
    PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_USART1;
    PeriphClkInitStruct.Usart16ClockSelection = RCC_USART16CLKSOURCE_D2PCLK2;
    if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK)
    {
      Error_Handler();
    }

/* Peripheral clock enable */
    __HAL_RCC_USART1_CLK_ENABLE();

__HAL_RCC_GPIOA_CLK_ENABLE();
    __HAL_RCC_GPIOB_CLK_ENABLE();
    /**USART1 GPIO Configuration
    PA9     ------> USART1_TX
    PB15     ------> USART1_RX
    */
    GPIO_InitStruct.Pin = GPIO_PIN_9;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF7_USART1;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

GPIO_InitStruct.Pin = GPIO_PIN_15;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF4_USART1;
    HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

/* USER CODE BEGIN USART1_MspInit 1 */

/* USER CODE END USART1_MspInit 1 */
  }
```

现在的情况就是slave模拟软件这边窗口只看到了RX，没有TX，在freemodbus测试的时候，RX\TX都是有的，不知道libmodbus为什么没有
测试图如下：
![image.png](https://oss-club.rt-thread.org/uploads/20210804/045ab8399e288c7aab36e23c863513b0.png.webp)
![image.png](https://oss-club.rt-thread.org/uploads/20210804/26c1e30aa35aa1dbea97dc2f8ab7d9b1.png)