MIDI synth with YM3812 & SAA1099 - Page 1
Forum section: electronics / projects

author: Dajgoro
author_rank: Frequent Contributor
timestamp: September 07, 2013, 07:25:40 pm
content: As you may already seen in other topics, I am building a MIDI synth with two vintage synth chips, the YM3812 and the SAA1099, where the MCU is the ATmega162. The project is going well, I managed to get the SAA1099 to play incoming MIDI notes, and use all of the 6 frequency generators, so I can get polyphonic tunes out of it. I am still waiting for a new YM3812 to sort out the mystery with that chip that I started another topic already. When using FL Studio i tend to get all sorts of unusual MIDI codes. Instead of getting the classical 0x90 note on with a proper velocity setting I get 0 velocity, which is actually note off. Then when using the sequencer option, it ends some other weird codes, which are actually some timing codes, so I end up receiving no midi on/off 0x80/0x90 codes.I also noticed that proper synthesizer keyboards have all sorts of pots for tweaking the envelope, modulation, and various effects, but I don't have such a keyboard, I only have a miniature one that I built myself.So could somebody explain what does a proper MIDI keyboard offer, and what should I implement in this device, and also what are all of those unusual codes that FL Studio 10 gives me out.

author: Arp
author_rank: Unknown
timestamp: September 07, 2013, 08:14:18 pm
content: Are those active sensing messages? I remember being flooded with thoseYou can find the MIDI specifications here:http://www.midi.org/techspecs/midimessages.php

author: Dajgoro
author_rank: Frequent Contributor
timestamp: September 07, 2013, 10:56:31 pm
content: I know about that code table, but the question is what do I do with that codes. I don't know how they should actually be interpreted.

author: casinada
author_rank: Frequent Contributor
timestamp: September 08, 2013, 12:24:17 am
content: http://www.midi.org/techspecs/Not all the instruments implement proper Midi specially the ones before General midi Came out. Even my Yamaha EX5 has some Midi bugs. At certain point the manufacturer decides that the product is good enough and they don't fix bugs any longer. Nobody is immune to that, Roland, Korg, Yamaha, etc.I haven't played with musical instrument or Midi for a long time but I think that you can filter midi in ways that it will restrict the commands that will reach certain device.Good luck with your project

author: Dajgoro
author_rank: Frequent Contributor
timestamp: September 08, 2013, 01:23:19 am
content: Quote from: casinada on September 08, 2013, 12:24:17 amThanks.If I don't figure out all of those extra codes, I'll just ignore them, and stick with the basic stuff.Anyway, I was also thinking about building a MIDI sequencer machine that could be programmed in various ways, so I wouldn't need a pc for making music anymore(my best musical composition ever was playing an accord).

author: AndreasF
author_rank: Frequent Contributor
timestamp: September 08, 2013, 02:35:41 pm
content: Yes, ignoring MIDI messages that don't seem to make any sense is a perfectly viable option, and it's something pretty much every MIDI instrument does to some degree or another. Often you would get a table towards the end of an instrument's manual that shows (more or less) exactly which MIDI messages are responded to, and which ones get ignored.