ユーザーフォーラム Campbell Scientific ユーザーのための 24 時間年中無休のリソース（英語のみの対応です）

I've had a bit of trouble trying to receive (unsigned) bytes since using the 32.02 OS.

Previously I've done this which is a bit of a hack but this works on 28.02. 

Function ReveiveByte() As Long
  Dim reveivedByte As Long
  If SerialInChk(TCP_Socket) > 0
    SerialInBlock(TCP_Socket,reveivedByte,1)
    RXval = reveivedByte >> 24
    If (RXval < 0)
      RXval = 127 + (129 + RXval) ' "undo" two's compliment
    EndIf
    Return RXval
  Else
    Return 256
  EndIf
EndFunction

I had to do this as there is no 'byte' data type available for variables. The byte gets received as a long and then appropriately bit shifted, then I have to undo two's compliment to get the correct value.

Since the new OS this doesn't work. The way longs are stored seems to have changed. I can't even seem to work out a way to bitshift my long to get a byte out of it, there seems almost no logic to it. I can confim with the terminal serial sniffer that the bytes are being received correctly. Strings won't work as it's binary data and are null terminated.

The reason I need a sudo byte data type is to calculate an 8-bit CRC which is used by a sensor. Is there a better way to do this? I really just want to be able to receive a serial byte and put it into a long. (Not worried at all about the overhead to this.)

Really wanting to switchover to the new OS for other reasons...

Any solution for this?

Change what you have:

  RXval = reveivedByte >> 24
    If (RXval < 0)
      RXval = 127 + (129 + RXval) ' "undo" two's compliment
    EndIf

To the following:

  RXval = reveivedByte >> 24
    If (RXval AND &H80)
      RXval =  256 - RXval ' "undo" two's compliment
    EndIf