STM32F103 : Receive Issue via USB COM port on Windows VISTA/7/8

[SURLEAU.Frederic]

Posted on May 18, 2017 at 10:28

Attached :

• C2_USB_TEST.ioc

• main.c

  https://community.st.com/message/157456/edit?draftID=16878

• stm32f1xx_it.c

MCU : STM32F103CBT6

STM32CubeMX : 4.21.0Firmware Package for Family STM32F1 : 1.4.0System Workbench for STM32 - OpenOCD (for Windows 32bits) Version: 1.14.0.201705091103

Modifications in main.c :

  /* USER CODE BEGIN 0 */  #define RAM_BOOT_LOADER_SIGNATURE_VALUE     0xDEADBEEF  #define RAM_BOOT_LOADER_SIGNATURE_ADDRESS     0x20004FF0  void Go_To_ST_Loader()  {      *((unsigned long *)RAM_BOOT_LOADER_SIGNATURE_ADDRESS) = RAM_BOOT_LOADER_SIGNATURE_VALUE; // 20KB STM32F103      HAL_NVIC_SystemReset();  }  //----------------------------------------------------------------------------

  char usb_buffer[64];

  char usb_flag;  /* USER CODE END 0 */  /* USER CODE BEGIN 1 */  int l;  char x[64];  int i = 0;  /* USER CODE END 1 */

  /* USER CODE BEGIN 2 */

  // Activate USB device detection (1.5khoms)  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_7, GPIO_PIN_SET);  /* USER CODE END 2 */

  /* USER CODE BEGIN 3 */

      if( usb_flag )      {          sprintf( x, 'usb:'%.*s'\r\n', usb_flag, usb_buffer );          usb_flag = 0;          if( ! memcmp( usb_buffer, 'loader', 6 ) )          {              Go_To_ST_Loader();          }          CDC_Transmit_FS( x, l );      }      else      {          HAL_Delay(1000);          l = sprintf( x, 'cpt = %d\r\n', i++ );          CDC_Transmit_FS( x, l );      }

  }

  /* USER CODE END 3 */Modifications in usbd_cdc_if.c :   static int8_t CDC_Receive_FS (uint8_t* Buf, uint32_t *Len)  {    /* USER CODE BEGIN 6 */      extern char usb_buffer[64];      extern char usb_flag;      if(*Len)      {          usb_flag = *Len;          memcpy( usb_buffer, Buf, usb_flag );      }    USBD_CDC_SetRxBuffer(&hUsbDeviceFS, &Buf[0]);    USBD_CDC_ReceivePacket(&hUsbDeviceFS);    return (USBD_OK);    /* USER CODE END 6 */   }

Windows 10 Microsoft driver 10.0.14393

  => Device detected as : Périphérique série USB (COMn)  Results : Usb communication OK in both directions.

Same Windows 10 as previous but with ST 'Virtual comport driver' 1.4.0

  => Device detected as : STMicroelectronics Virtual COM Port (COMn)  Results : Usb communication OK in both directions.

Windows 7 Pro-64   with ST 'Virtual comport driver' 1.4.0

Windows 8.1-64    with ST 'Virtual comport driver' 1.4.0Windows Vista-32  with ST 'Virtual comport driver' 1.4.0  => Device detected as : STMicroelectronics Virtual COM Port (COMn)  Results : Usb communication only in one direction PC to Device.

I know communication is good in the direction PC to device, because when I send 'loader' to virtual COM port, the device switches to STLoader.

How can I fix this problem ?

Fred.