All geek questions in one place

Error opening serial port

I am trying to open and read from a serial port using the System.IO.Ports.SerialPort class. I dragged the serial port from the toolbar (VS 2008) into my window form. I have a property grid, so I can easily change the properties of the serial port at runtime. When I try to open the port, I get the error shown below. I do not understand why, because I can open and read from a port using Hyperterminal. Any ideas?

System.IO.IOException Error connection: A device attached to the system is not functioning
   at System.IO.Ports.InternalResources.WinIOError(Int32 errorCode, String str)
   at System.IO.Ports.InternalResources.WinIOError()
   at System.IO.Ports.SerialStream.set_DtrEnable(Boolean value)
   at System.IO.Ports.SerialStream..ctor(String portName, Int32 baudRate, Parity parity, Int32 dataBits, StopBits stopBits, Int32 readTimeout, Int32 writeTimeout, Handshake handshake, Boolean dtrEnable, Boolean rtsEnable, Boolean discardNull, Byte parityReplace)
   at System.IO.Ports.SerialPort.Open()
   at Test.CardReader.frmMain.Connect() in D:\Develop\2.0\Projects\Kiosk\EmbeddedBrowser\Windows Forms\Test.CardReader\Form1.cs:line 166

Please note that this is a USB connection, therefore it activates a virtual serial port. My settings are as follows:
BaudRate = 9600
DataBits = 8
DiscardNull = false
DtrEnable = false
Handshake = No
Parity = No
ParityReplace = 63
PortName = COM3
ReadBufferSize = 4096
ReadTimeout = -1
ReceivedBytes = 1
TrsEnable = False
StopBits = one
WriteBufferSize = 2048
WriteTimeout = -1

I downloaded PortMon from sysinternals. I grabbed 2 logs, the first is the log, as happens when Hyperterminal opens the port, the second is what happens when the .net SerialPort class tries to open the port:

Hyperterminal:

IRP_MJ_CREATE                   USBSER000   SUCCESS         Options: Open 
IOCTL_SERIAL_SET_QUEUE_SIZE     USBSER000   SUCCESS         InSize: 8192 OutSize: 8192
IOCTL_SERIAL_CONFIG_SIZE        USBSER000   SUCCESS         Size: 0
IOCTL_SERIAL_GET_BAUD_RATE      USBSER000   SUCCESS 
IOCTL_SERIAL_GET_LINE_CONTROL   USBSER000   SUCCESS 
IOCTL_SERIAL_GET_CHARS          USBSER000   SUCCESS 
IOCTL_SERIAL_GET_HANDFLOW       USBSER000   SUCCESS 
IOCTL_SERIAL_GET_BAUD_RATE      USBSER000   SUCCESS 
IOCTL_SERIAL_GET_LINE_CONTROL   USBSER000   SUCCESS 
IOCTL_SERIAL_GET_CHARS          USBSER000   SUCCESS 
IOCTL_SERIAL_GET_HANDFLOW       USBSER000   SUCCESS 
IOCTL_SERIAL_SET_BAUD_RATE      USBSER000   SUCCESS         Rate: 9600
IOCTL_SERIAL_SET_RTS            USBSER000   SUCCESS 
IOCTL_SERIAL_SET_DTR            USBSER000   * 0xC0000001    
IOCTL_SERIAL_SET_LINE_CONTROL   USBSER000   SUCCESS         StopBits: 1 Parity: NONE WordLength: 8
IOCTL_SERIAL_SET_CHAR           USBSER000   SUCCESS         EOF:1a ERR:0 BRK:0 EVT:1a XON:f6 XOFF:6
IOCTL_SERIAL_SET_HANDFLOW       USBSER000   SUCCESS         Shake:80000001 Replace:80000040 XonLimit:80 XoffLimit:200
IOCTL_SERIAL_SET_TIMEOUTS       USBSER000   SUCCESS         RI:10 RM:0 RC:0 WM:0 WC:5000
IOCTL_SERIAL_SET_WAIT_MASK      USBSER000   SUCCESS         Mask: RLSD ERR 
IOCTL_SERIAL_GET_MODEMSTATUS    USBSER000   SUCCESS 
IOCTL_SERIAL_WAIT_ON_MASK       USBSER000       
IRP_MJ_READ USBSER000                                       Length 80

.Net SerialPort:

IRP_MJ_CREATE                   USBSER000   SUCCESS Options: Open 
IOCTL_SERIAL_GET_PROPERTIES     USBSER000   SUCCESS 
IOCTL_SERIAL_GET_MODEMSTATUS    USBSER000   SUCCESS 
IOCTL_SERIAL_GET_BAUD_RATE      USBSER000   SUCCESS 
IOCTL_SERIAL_GET_LINE_CONTROL   USBSER000   SUCCESS 
IOCTL_SERIAL_GET_CHARS          USBSER000   SUCCESS 
IOCTL_SERIAL_GET_HANDFLOW       USBSER000   SUCCESS 
IOCTL_SERIAL_GET_BAUD_RATE      USBSER000   SUCCESS 
IOCTL_SERIAL_GET_LINE_CONTROL   USBSER000   SUCCESS 
IOCTL_SERIAL_GET_CHARS          USBSER000   SUCCESS 
IOCTL_SERIAL_GET_HANDFLOW       USBSER000   SUCCESS 
IOCTL_SERIAL_SET_BAUD_RATE      USBSER000   SUCCESS Rate: 9600
IOCTL_SERIAL_CLR_RTS            USBSER000   SUCCESS 
IOCTL_SERIAL_CLR_DTR            USBSER000   * 0xC0000001    
IOCTL_SERIAL_SET_LINE_CONTROL   USBSER000   SUCCESS StopBits: 1 Parity: NONE WordLength: 8
IOCTL_SERIAL_SET_CHAR           USBSER000   SUCCESS EOF:1a ERR:0 BRK:0 EVT:1a XON:11 XOFF:13
IOCTL_SERIAL_SET_HANDFLOW       USBSER000   SUCCESS Shake:0 Replace:0 XonLimit:4096 XoffLimit:4096
IOCTL_SERIAL_GET_BAUD_RATE      USBSER000   SUCCESS 
IOCTL_SERIAL_GET_LINE_CONTROL   USBSER000   SUCCESS 
IOCTL_SERIAL_GET_CHARS          USBSER000   SUCCESS 
IOCTL_SERIAL_GET_HANDFLOW       USBSER000   SUCCESS 
IOCTL_SERIAL_SET_BAUD_RATE      USBSER000   SUCCESS Rate: 9600
IOCTL_SERIAL_CLR_RTS            USBSER000   SUCCESS 
IOCTL_SERIAL_CLR_DTR            USBSER000   * 0xC0000001    
IOCTL_SERIAL_SET_LINE_CONTROL   USBSER000   SUCCESS StopBits: 1 Parity: NONE WordLength: 8
IOCTL_SERIAL_SET_CHAR           USBSER000   SUCCESS EOF:1a ERR:0 BRK:0 EVT:1a XON:11 XOFF:13
IOCTL_SERIAL_SET_HANDFLOW       USBSER000   SUCCESS Shake:0 Replace:0 XonLimit:4096 XoffLimit:4096
IOCTL_SERIAL_CLR_DTR            USBSER000   * 0xC0000001    
IRP_MJ_CLEANUP                  USBSER000   SUCCESS 
IRP_MJ_CLOSE                    USBSER000   SUCCESS
+3
4

.NET, Hyperterminal - , . , Hyperterminal . .NET , .NET, .

:

  • , , , , . , .
  • , .
  • , , , ( ). .
  • , . , , ,... .

DTR false , . SerialPort .NET. , , .

, USB. - , - .

+4

UART, DTREnable DTR UART, , .

DTREnable true, .

+1

. , . , Hyperterminal. . , , Hyperterminal -.

0

it looks like the difference is in making a connection.

I had no problems with the serialport class and applications with a speed of 800,000 bps were written.

0
source

Source: https://habr.com/ru/post/1702490/

More articles:


All Articles