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J1939CalcChecksum

Valid for: CANoe DE • CANoe4SW DE Note
This function has been completely revised with CANoe DE product version 15. The former variant J1939CalcChecksum (Obsolete) is deprecated.

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Function Syntax

J1939CalcChecksum(pg * msg, char[] calculationMethod, dword & checksum)

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Description

Provides the checksum calculation for all PGNs as described in the J1939 Digital Annex. Possible calculation algorithms and message counter alignment is described in J1939 Functional Safety – Messages With Integrated Checksum and Counter.

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Parameters

  • msg: The parameter group to calculate the checksum for.
  • calculationMethod: Two letters in the form [A-E][a-f] (e.g. Bc) that define the calculation rule and position of the checksum and message counter.
  • checksum: Out parameter where the checksum is stored.

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Return Values

  • 0: Checksum is successfully filled.
  • -1: Error: calculation method is invalid.

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Example

on pg *
{
  long err;
  dword checksum;
  switch(this.pgn)
  {
    case 0xF123: //DCDC4OS
      err = J1939CalcChecksum(this, "Aa", checksum);
      if(checksum != this.byte(7) || err != 0)
      {
        write("Checksum error");
      }
      break;
    default:
      break;
  }
}