LUA Calculating Hex Checksum

[johnp]

Any ideas on how I can use LUA to calculate a hex checksum on a string of bytes?

Thanks.

[Rob H]

We need more information - what sort of checksum? Do you have an algorithm for the checksum computation or a bit of existing program code in another language?

[johnp]

Just need to do a simple add on a series of 14 hex byte result should be 16 bit word

Format is as follows:

Byte 0 0xFFh
Byte 1 0xAAh
Byte 2 0x00h
Byte 3 0x01h
Byte 4 0x82h
Byte 5 0x09h
Byte 6 0x00h - 0x3Bh
Byte 7 0x00h - 0x17h
Byte 8 0x00h - 0xFFh
Byte 9 0x00h - 0xFFh
Byte 10 0x00h - 0xFFh
Byte 11 0x00h - 0xFFh
Byte 12 0x00h - 0xFFh
Byte 13 0x00h - 0xFFh
Byte 14 0x00h - 0xFFh
Byte 15 Hi Byte of Checksum 0x??h
Byte 16 Lo Byte of Checksum 0x??h

So if I manually calculated the above, with alll variables set to 0x00h the resultant sum would be 235 which would make byte 15 0x02h and byte 16 0x35h

So if I could just figure out how to convert a byte from hex to decimal then add it up and then covert it back to hex, or alternatively do hex addition, I would be set, but I just can't figure that out...

Thanks as always.

[Rob H]

If you read the Girder help file - Lua library reference\math library - near the end you'll find various conversion functions.

[johnp]

Many Thanks.