Monday, April 23, 2007 8:58 AM
I am using in "SerialPort_DataReceived" event to received data from serial port.
I would like to use "TimeoutException" for "ReadTimeout" and set it to 1 sec.
How can I integrate "TimeoutException" with "SerialPort_DataReceived"?
See sample relevant code:
Public Class Serial_Port_Form
Private Sub SendButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles SendButton.Click
Dim XmtBuffre(5) As Byte
XmtBuffre(0) = ENUM_OPCODE_TYPE.EN_WRITE_FLASH_CMD_LSB
XmtBuffre(1) = ENUM_OPCODE_TYPE.EN_WRITE_FLASH_CMD_MSB
XmtBuffre(2) = BytesNumberLSB
XmtBuffre(3) = BytesNumberMSB
ChecksumLSM = ENUM_OPCODE_TYPE.EN_WRITE_FLASH_CMD_MSB Xor _
ENUM_OPCODE_TYPE.EN_WRITE_FLASH_CMD_LSB Xor _
BytesNumberLSB Xor BytesNumberMSB
For i = 0 To (XmtBuffre.Length - 3)
ChecksumLSM = ChecksumLSM Xor XmtBuffre(i)
XmtBuffre(4) = ChecksumLSM
XmtBuffre(5) = ChecksumMSM
SerialPort.Write(XmtBuffre, 0, XmtBuffre.Length)
Public Err As New IO.Ports.SerialError
Public WithEvents SerialPort As New IO.Ports.SerialPort
Public RxWholeBuffer As New ArrayList
Private Sub SerialPort_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort.DataReceived
Count = SerialPort.BytesToRead
Dim RxSubBuffer(0 To Count - 1) As Byte
SerialPort.Read(RxSubBuffer, 0, Count)
Monday, April 23, 2007 10:24 AM
Hopefully I have understood what you are seeking; if not, please accept my apologies.
The call to the Write method is blocking therefore the timeout exception can be raised by it ....
serialPort.WriteTimeout = 1000Try : serialPort.Write(msg, 0, msg.Length) Catch ex As TimeoutException ...........
Is that what you were seeking?
Wednesday, April 25, 2007 6:31 AM
Thanks Ricdard, sorry it is not what I am looking for.
Somebody, any ideas…
Wednesday, April 25, 2007 8:34 AMCan you explain a little more with regards to the problem you are facing / the needs of your application?
Monday, April 30, 2007 7:06 AM
My application communicates with external device under RS232 or RS485.
I need to implement the following requirements:
Retransmission is required when one of the following scenarios occurs:
§ Only part of the message received (not all N bytes arrived).
§ Checksum error.
§ Error occurred on communication port.
1) Retransmission every 1 second (Timeout).
2) Maximum 3 retransmissions – when 3 failed send Error NACK message.