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After over a year of development, I would like to start documenting my Midibox_NG project in this thread to collect as much information as possible for similar future projects. The idea is to keep all findings, questions and struggles concerning this projects in one thread to keep myself organised and to help future digital/analog synth developers. As the title predicts, the goal of this project is to design and develop an all in one box digitised analog synth, similar to the MiniMoog Voyager. The synth will be controlled solely over midi. An LPC17 with Midibox_NG running acts as the main brain to read digital pots and switches of the control panel, save and recall presets as well as to drive the synth through multiple analog and digital outputs. Analog synth hardware: 1x LFO 2x Modulation Bus 3x VCO incl. waveshapers as well as additional loops for other effects than the waveshapers (documented on: http://www.muffwiggler.com/forum/viewtopic.php?t=108794) 1x Noise generator 1x Ext_In 1x Mixer stage 1x 5Pulser (http://home.comcast.net/~ijfritz/sy_cir8.htm) 1x Ring modulator 1x Phaser effect 2x Moog ladder LP filter (to create a stereo effect through filter cutoff spacing) 1x Moog T904B HP filter (to create a band pass together with one of the LP filters (http://www.freeinfosociety.com/electronics/schemview.php?id=944) 2x ADSR (for filter and volume) 1x Stereo VCA 1x Headphone preamp 1x +/-15V & +5V switching power supply (I learned, that it is much easier to develop circuits with the additional "headroom" of +/-3V in comparison to a +/-12V supply) 1x Power board to generate +/-12V for the AOUT_NG modules as well as +10V clean reference voltage. Resources All the analog circuits are redesigned and relayouted to be uC controllable. They are mainly based on the following modules: - Ninni Bergfors' Moog based bergfotron modules (http://hem.bredband.net/bersyn/) - Original Moog D schematics (http://www.fantasyjackpalance.com/fjp/sound/synth/synthdata/16-moog-minimoog.html) - Original Micromoog schematics (http://www.fantasyjackpalance.com/fjp/sound/synth/synthdata/07-moog-micromoog.html) - Yves Usson's Yusynth (http://yusynth.net/Modular/index_en.html) - René Schmitz's modules (http://www.schmitzbits.de/) - Carsten Toensmann's Moog Modular Clone (http://www.analog-monster.de/mmschemos.html) - Vinnui's Modbus concept (http://vinnui.blogspot.ch/2011/09/concept-of-modulation-bus.html) The original idea was to use the Moog D schematics solely and as many original parts as possible. But after already acquiring many old parts for a reasonable amount of money, I dumped the idea when the last Chinese seller of UA726 remakes went off market. However, I don't regret the decision, as I am very happy with my results so far with more modern parts, which are not nearly as energy hungry as the old stuff. Midibox Hardware: 1x LPC17 core module 1x KS0108 based graphic LCD 1x SD card reader 1x AINSER64 module 1x DIO_MATRIX module 1x DOUT module (own design with partly high power shift registers for switching relays) 4x AOUT_NG modules Development Roadmap (fully implemented, partly done, not touched yet): - HARDWARE Power Board - HARDWARE Midibox modules (excl. DOUT) - HARDWARE VCO & waveshaper board (incl. trimming & tuning) - HARDWARE LP filter - HARDWARE HP filter & filter switching circuit - HARDWARE 5Pulser - HARDWARE Ring Modulator (on the breadboard and PCB layouted) - HARDWARE ADSR (PCB layouted) - HARDWARE DOUT module - HARDWARE control panel pots & switches - HARDWARE Mixer including overdrive LED circuit - HARDWARE VCA & headphone preamp - HARDWARE LFO, MOD BUS, Noise generator circuits and PCB - HARDWARE Casing - HARDWARE Phaser (planned as a seperate module, since not enough AOUTS available) - SOFTWARE Utilising AINSER64 and AOUT_NG at one port () - SOFTWARE Controlling multiple AOUT_NG modules at once () - SOFTWARE VCO octave switch option (thanks TK) - SOFTWARE Multiple rotary switches locking each other out (softwarebug ironed out, thanks again, TK) - SOFTWARE Controlling Digital switching ICs (binary input) by DOUTs (signal switching related topic) - SOFTWARE synth fine tuningrange (+/- 3 semitones, steps as fine as possible) -> solved in the analog section, without midibox assistance - SOFTWARE VCO detuning -> semitone detuning works, free detuning not implemented in MBNG) - SOFTWARE Midibox_NG menu structure -> initial work done - SOFTWARE Preset save and recall - SOFTWARE Midi control of parameters (excl. tone & pitch bend)

I heard about MIDIbox some time ago from a dear friend. Not realizing its potential at the time, it ended up somewhere in the back of my head. However, now that I am planning to build an analog(ish) synthesizer, I can start to see attraction of the system. My question is this: How much will the CORE_LPC17 board be able to process at a time? Here follows a list of functions: Scan a 49 key keyboard, using a six-bit polyphonic decoder. (Requires six Douts and one Din) Mix note events from the keyboard into the external MIDI stream. An internal clock, with tempo derived from either a pot or tapping. A basic arpeggiator with the following functions: Up, down, up-down, down-up, random, or order pressed modes. Run over 4 octaves. Semibreve, crotchet, quaver, semi-quaver, etc... based on clock input, from either the external input or the internal clock. Gate length (PW) controlled via pot. Output a CV, a gate, and clock pulse (to LFOs) Potentially a MIDI output, combining the data from the original MIDI stream, the keyboard, the internal clock (if being used), and the output from the arpeggiator on a separate channel. I think that is all for now. Shall write back if I remember something else... So, would the core board be able to process all of this simultaneously? Regards, Steve.