GenMDM Version 2 PCB 5V Jumper Function

The GenMDM Version 2 PCB contains two main changes to the hardware compared with the Version 1 PCB. These changes are:

• A 5 pin DIN MIDI input connection with associated optocoupler and components
• A 5 volt jumper

The function of the jumper is as follows.

When the jumper is connected, as shows in the photo above, then the SEGA console will power the GenMDM hardware including the 5 pin DIN MIDI input connection.

Use this jumper in the connected position when using the GenMDM with a traditional 5 pin DIN connection. Do not use this jumper in the connected position when using the GenMDM with a USB cable at all. Never connect a USB cable to the GenMDM unit when the jumper is in the connected position. Doing so may damage the GenMDM.
 

When the jumper is disconnected, as shows in the photo above, then USB cable will power the GenMDM hardware. The 5 pin DIN MIDI input connection will not be powered, and a traditional 5 pin DIN connection will not work.

Use this jumper in the connected position when using the GenMDM with a USB cable for MIDI data or for firmware updates. This will provide 5V to the GenMDM hardware via the USB cable.

GenMDM PCB Version 1 Modification: SEGA Console Power

The GenMDM interface version 1 PCB can be powered from the SEGA console by performing this simple modification.

This modification will reduce noise in the audio output of the SEGA console, but it will also render the Teensy microcontroller board unable to be powered via USB cable alone.

This may make it unsuitable for people that wish to use their GenMDM Teensy boards for other things.

Take a GenMDM version 1 PCB.

Solder a wire to pin 5 of the 9-pin connector.

Solder the other end of the wire to the VCC pin header of the Teensy socket

Take your GenMDM Teensy. Note the underside. There is a series of three pads marked 3V 5V. Cut the trace that is between the middle pad and the pad next to the 5V sign. A clear diagram is given here.

This is the Teensy after the trace has been cut. Ensure that there is not connection between the two pads by using a multimeter to check resistance (or lack thereof).

Insert the Teensy board back into the cradle.

GenMDM Batch 2 PCB Constructed

GenMDM with 5 pin DIN and USB connections. Tested and works!

.GENM File Format: GenMDM Instrument Patch File Specifications

A .GENM file is used to store GenMDM patch files.

Each patch file can store up to 128 different instrument settings for an FM channel of a GenMDM interface.

A .GENM file is in a standard text format.

Each instrument is stored in the following way:
[Instrument Index], [Algorithm] [LFO FM] [LFO AM] [FM Feedback] [Panning] [OP1 Level] [OP2 Level] [OP3 Level] [OP4 Level] [OP1 Detune] [OP2 Detune] [OP3 Detune] [OP4 Detune] [OP1 Attack] [OP2 Attack] [OP3 Attack] [OP4 Attack] [OP1 Decay 1] [OP2 Decay 1] [OP3 Decay 1] [OP4 Decay 1] [OP1 Decay 2] [OP2 Decay 2] [OP3 Decay 2] [OP4 Decay 2] [OP1 Mul] [OP2 Mul] [OP3 Mul] [OP4 Mul] [OP1 Rate Scaling] [OP2 Rate Scaling] [OP3 Rate Scaling] [OP4 Rate Scaling] [OP1 Amp2] [OP2 Amp2] [OP3 Amp2] [OP4 Amp2] [OP1 Release] [OP2 Release] [OP3 Release] [OP4 Release] [OP1 LFO Enable] [OP2 LFO Enable] [OP3 LFO Enable] [OP4 LFO Enable] [OP1 SSG Data] [OP2 SSG Data] [OP3 SSG Data] [OP4 SSG Data] [Instrument Name Symbol String];

• Instrument index is indexed at 0
• Instrument index does not need need to be in order in the file
• TL is given as 127 - TL for each level parameter for each operator
• LFO enable is 0 for not enabled, 1 for enabled
• All other data fields are given as actual register data, not unscaled raw data
• Instrument name can be up to 256 characters long

GenMDM Polyphonic Handling App

// GDAY M8s //

Normally, the GenMDM is monophonic i.e. each MIDI channel is directly mapped to a chip voice (1 - 6 for FM, 7 - 10 for PSG). As a result, each MIDI channel can only play one note at a time, as a single chip voice can only make one sound at a time.

Tonight I made a simple polyphonic handler for both the FM chip and the PSG chip of the SEGA Mega Drive. 

Usage is very simple: 

• Create a MIDI track in Live / Logic / ProTools / whatever

• Sequence a chord on this track with up to 6 notes

• Send the output of this track along channel 1 of a virtual MIDI bus (e.g. IAC MIDI bus 1 for OS X)

• In the GENMDM_POLY app, choose the same virtual MIDI bus as the input

• In the GENMDM_POLY app, choose the GenMDM as the output
• The level of polyphony for the FM and PSG chips are set by the user (2 - 6 voices for the FM and 2 - 3 voice for the PSG)

• Chords will automatically routed to GenMDM channels 1 - 6 without any effort whatsoever

• If you gave a stuck note, use the "KILL NOTES" button to stop it

• A chord with up to six notes should be routed to the FM chip via MIDI channel 1 (channels 2 - 6 should not be used)

• A chord with up to three notes should be routed to the PSG chip via MIDI channel 7 (channels 7 - 10 should not be used)

Download OS X application here: http://little-scale.com/GENMDM/GENMDM_APPS/GENMDM_POLY/GENMDM_POLY_SOURCE/GENMDM_POLY.maxpat.zip

Download Max patch here: http://little-scale.com/GENMDM/GENMDM_APPS/GENMDM_POLY/GENMDM_POLY_OSX/GENMDM_POLY.zip 

// THANKS FOR WATCHING && TREAD UR OWN PATH //

GenMDM Firmware v100 Quick Reference MIDI Mapping

=====================================================================================
GenMDM Firmware v100 - Quick Reference MIDI Mapping by little-scale
http://www.little-scale.blogspot.com.au/
seb.tomczak@gmail.com
=====================================================================================
Firmware v100 Version Information: 
* Initial release
=====================================================================================
MIDI Channel Sound Chip Mapping
* YM2612 FM sound chip is mapped to MIDI channels 1 - 6. 
* SN76489 PSG sound chip is mapped to MIDI channels 7 - 10.
=====================================================================================
YM2612 FM Sound Chip Mapping
-------------------------------------------------------------------------------------
Parameter      CC  Data Range
* LFO Enable (Global)     74  2
* LFO Speed       1  8 
* Pitch Transposition     85  128
* Octave Division     84  128
* PAL / NTSC Tuning     83  2
-------------------------------------------------------------------------------------
Channel / Voice Control     CC  Data Range
* Preset Instrument Setting    9  16
* Frequency      Note Number 128
* Pitch Bend Amount     81  18
* FM Algorithm      14  8
* FM Feedback      15  8
* Stereo Configuration     77  4
* Amplitude Modulation Level    76  8
* Frequency Modulation Level    75  8
-------------------------------------------------------------------------------------
Operator Control      CC  Data Range
* Total Level OP 1     16  128
* Total Level OP 2     17  128
* Total Level OP 3     18  128
* Total Level OP 4     19  128
* Multiple OP 1      20  16
* Multiple OP 2      21  16
* Multiple OP 3      22  16
* Multiple OP 4      23  16
* Detune OP 1      24  8
* Detune OP 2      25  8
* Detune OP 3      26  8
* Detune OP 4      27  8
* Rate Scaling OP 1     39  4
* Rate Scaling OP 2     40  4
* Rate Scaling OP 3     41  4
* Rate Scaling OP 4     42  4
* Attack Rate OP 1     43  32
* Attack Rate OP 2     44  32
* Attack Rate OP 3     45  32
* Attack Rate OP 4     46  32
* First Decay Rate OP 1     47  32
* First Decay Rate OP 2     48  32
* First Decay Rate OP 3     49  32
* First Decay Rate OP 4     50  32
* Secondary Decay Rate OP 1    51  16
* Secondary Decay Rate OP 2    52  16
* Secondary Decay Rate OP 3    53  16
* Secondary Decay Rate OP 4    54  16
* Secondary Amplitude Level OP 1   55  16
* Secondary Amplitude Level OP 2   56  16
* Secondary Amplitude Level OP 3   57  16
* Secondary Amplitude Level OP 4   58  16
* Release Rate OP 1     59  16
* Release Rate OP 2     60  16
* Release Rate OP 3     61  16
* Release Rate OP 4     62  16
* Amplitude Modulation Enable OP 1   70  2
* Amplitude Modulation Enable OP 2   71  2
* Amplitude Modulation Enable OP 3   72  2
* Amplitude Modulation Enable OP 4   73  2
-------------------------------------------------------------------------------------
DAC Control (MIDI Channel 6)     CC  Data Range
* DAC Enable      78  2
* DAC Direct Data     79  128
* DAC Sample Pitch Speed    86  128
* DAC Sample Oversample     88  16
* DAC Noise  / Custom Wave Mode    89  2
* Custom Wave Byte 1 of 14    100  128
* Custom Wave Byte 2 of 14    101  128
* Custom Wave Byte 3 of 14    102  128
* Custom Wave Byte 4 of 14    103  128
* Custom Wave Byte 5 of 14    104  128
* Custom Wave Byte 6 of 14    105  128
* Custom Wave Byte 7 of 14    106  128
* Custom Wave Byte 8 of 14    107  128
* Custom Wave Byte 9 of 14    108  128
* Custom Wave Byte 10 of 14    109  128
* Custom Wave Byte 11 of 14    110  128
* Custom Wave Byte 12 of 14    111  128
* Custom Wave Byte 13 of 14    112  128
* Custom Wave Byte 14 of 14    113  128
===================================================================================== SN76489 PSG Sound Chip Mapping
* Global Control      CC  Data Range
* Pitch Transposition     85  128
* PAL / NTSC      83  2
-------------------------------------------------------------------------------------
Noise Channel Control     Type
* C and C#      High Frequency; Periodic Type
* D and D#      Medium Frequency; Periodic Type
* E       Low Frequency; Periodic Type
* F       High Frequency; Noise Type
* F#       Medium Frequency; Noise Type
* G and G#      Low Frequency; Noise Type
* A and A#      Channel 9; Periodic Type
* B       Channel 9; Noise Type
=====================================================================================

Available as a text file here: http://little-scale.com/genmdm_100.txt

little-scale: I Am Still Breathing (2010) Out Now On Pause!

little-scale returns to Pause with an introspective release, making use of both the YM2612 FM chip and the SN76489 PSG. “Seb” weaves intricate textures and restful melodies with the luscious warmth of the SEGA Nomad.

Artwork by Lauren Tomczak.

Listen here: http://www.iimusic.net/catalog/2010/12/little-scale-i-am-still-breathing

SEGA Nomad Whistling Follower Video

By popular demand, this is a quick demo video of the patch that I blogged about earlier. There is an intentional delay between my whistling and the SEGA Nomad resynthesis. The echo / repeats heard after are due to a feedback loop between the SEGA Nomad's speaker output and the resynthesis input.

SEGA Nomad and Max/MSP Whistling Follower / Resynthesis

I like whistling. In fact, in the past I've even led and organised whistling ensembles. I also like chiptune. So I wanted to combine the two. How better to achieve this combination than to have a SEGA Nomad 'whistling' back to me / along with me as I am whistling? So I made a basic FFT-based Max/MSP patch that sends out MIDI data in real time (or with a delay) to the SEGA Nomad, which then plays the notes. The patch supports multiple partials spread across the six FM channels of the YM2612. I expect to develop this patch further so as to resynthesise different, more complex sounds than just human whistling (think speech etc). Let me know if you want to see a video of the 'Whistling Nomad' in action.

Freezedream / little-scale SEGA Mega Drive Cartridge Is Here!

Coova and little-scale on 8BitPeoples.com!

"After having met at Blip Festival 2009, Coova and little-scale signed a treaty to merge their respective battalions and combine their unique combat styles in order to ward off evil enemy forces. Coova’s artillery of choice is the Nintendo Game Boy with the Nanoloop 1.5 ammo cartridge whilst little-scale’s war science research department has developed a weaponised strain of the SEGA Nomad. The result is an armed force to be reckoned with, ready to do battle on any audio playback system at high volumes. "

Grab it here: http://www.8bitpeoples.com/discography

New Track on 8BC and Chipmusic.org "I Am Still Breathing"

For SEGA Nomad and Atari 2600. http://8bitcollective.com/music/little-scale/I+Am+Still+Breathing/

Waveform Buffer Editor for SEGA Mega Drive YM2612

As an extension to the previously mentioned triangle waveform mode, I have introduced additional routines that allow the user to set the waveform of that mode. These routines coupled with a handy Max/MSP patch allow for very easy waveform editing.

Triangle Bass Mode for SEGA Mega Drive YM2612

A quick trial. I've added a "triangle wave" mode to the previously mentioned noise channel mode for the SEGA Mega Drive MIDI Interface.

Noise Channel for SEGA Mega Drive YM2612

I have added a noise channel component for the FM chip of my SEGA Mega Drive MIDI Interface. The aim is to simply offer a little more variety in terms of what sounds can be achieved with the YM2612, so it's quite basic at the moment. The channel (which is actually a 'half channel' as it is split with FM channel six / the DAC channel) has the following features:

• 3 bit volume control is mapped to velocity
• 6 bit frequency control is mapped to pitch (specifically, notes 0 - 59)

A demo video is below.

little-scale: Office Yoga Made Easy

Office yoga made easy; hypnosis for the modern age. Music for SEGA Nomad and Atari 2600. Cure yourself with electricity.


Track listing:
1. We Are Eating Our Children
2. Four-Wheel Drive Advertisement
3. Plus One
4. Self Replicating Technology
5. Latitude and Longitude (CD-only track)
6. Microbiology


You can download this release here. You can also purchase a physical copy of this release here. Why would you want to do that? Well, (1) you might like to support what it is that I do (2) it's only $4 plus postage and (3) it contains an extra track.

The artwork contains elements by the Flickr user O'hAodha. Used under license.

Sega Mega Drive / Genesis Sound Comparison Page

URL: http://milkcrate.com.au/_other/sega_comparisons/

"There are many hardware and software options available to those that are writing music for the Sega Mega Drive / Genesis video game console. Each option has its own unique flavour of sound upon playback, in terms of tone colour, spectrum, clipping / overdriven waveforms, signal to noise ratio and the amplitude of the signal.

The aim of this page is to provide composers and musicians with an opportunity to listen to a number of the different models of Sega Mega Drive / Genesis. "

Sega Nomad MIDI Interface

I thought I would mention that my Sega Mega Drive / Genesis MIDI interface is now compatible with the Sega Nomad. Demo video here. As I often say with these sorts of updates, join the Gen/MDM Google Announcements Group to be notified of when this device will be available.