Trouble calculating a checksum.

[Hryniowski]

I'm trying to generate a 16 bit checksum from a .hex file I have, I've tried breaking the hexfile into a 1D array of 65476 elements and summing the individual elements but I keep getting the wrong answer.  Does anyone have an example of how to create a checksum from a file?  I've included what I have that isn't working.  I'm ignoreing the first 40K some odd elements because I know they are 0.

Thanks.

The equivalent C++ code is

for( UINT i = 0; i < (dwFileLength >> 1); i++ )

{

if ((pwImage[ i ] & 0xFFFF) != 0)

{

iChecksumPc += pwImage[ i ] & 0xFFFF;

}

}

[MehakD]

Hi

The reason that you are not getting the right checksum is probably because you are reading two hex characters at a time (in the for loop for the read). The two characters would only make up an 8 bit value and a not a 16 bit value. Therefore, I would recommend you to read 4 characters at time to perform a 16 bit checksum.

I hope this helpsl.

Mehak Dinesh

Applications Engineer

National Instruments

www.ni.com/support