Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!husc6!hao!noao!mcdsun!sunburn!gtx!edge!doug From: doug@edge.UUCP (Doug Pardee) Newsgroups: comp.sys.cbm,rec.music.synth Subject: C-64 MIDI interface programming info Message-ID: <882@edge.UUCP> Date: Fri, 24-Jul-87 17:52:55 EDT Article-I.D.: edge.882 Posted: Fri Jul 24 17:52:55 1987 Date-Received: Sun, 26-Jul-87 04:48:07 EDT Organization: Edge Computer Corporation, Scottsdale, AZ Lines: 17 Xref: mnetor comp.sys.cbm:589 rec.music.synth:1163 If anyone wants to program his C-64 MIDI interface, here are the basics... A 6840 Programmable Timer Module is mapped at $DE00-$DE07. It is driven off of the CPU clock (1.02 MHz for US/Canada NTSC C-64s). On those MIDI interfaces with Tape-Sync output, it is driven by the 6840's "Timer 1". A 6850 Asynchronous Communications Interface Adapter is mapped at $DE08- $DE09. It is driven by a 500 KHz clock. Both devices are connected to the C-64's interrupt line. The 6840 and 6850 are made by Motorola, Hitachi, Fairchild, I think Signetics, and maybe other companies. Data sheets are widely available. I'll be glad to supply more details via E-mail. -- Doug Pardee, Edge Computer Corp; ihnp4!mot!edge!doug, seismo!ism780c!edge!doug