Path: utzoo!attcan!uunet!samsung!zaphod.mps.ohio-state.edu!wuarchive!mit-eddie!uw-beaver!ubc-cs!van-bc!rsoft!mindlink!a708
From: a708@mindlink.UUCP (Gord Wait)
Newsgroups: comp.music
Subject: Re: MIDI SysEx Checksums (esp. Casio equipment)
Message-ID: <3669@mindlink.UUCP>
Date: 29 Oct 90 02:41:36 GMT
Organization: MIND LINK! - British Columbia, Canada
Lines: 8

Yamaha's olde DX7 checksum is the two's complement of the sum of the data
bytes: Ie add up all your data bytes, chop away anything over 8 bits (use a 32
bit add to keep the sign bit away..), invert the lowest 8 bits, (exchange 1's
for 0's, 0's for 1's) and add One to the final result. Unfortunately, there is
no standard in the sysex data for where the data to add starts amongst the
different Yamaha sysex data formats I've been working at...

Gord Wait