Midi2CV Mk2

Midi2CV Mk2 is a DIY embeddable MIDI to 4 x CV/Gate converter with extensive configuration options and extra modulation sources (LFO and AHDSR EG).

Midi2CV_mk2#1 (small)



  • +-12V or +-15V, Euro or MOTM power connector
  • 50mA@+15V, 10mA@-15V


  • 4 x CV channels, each could be 0+5V, 0+10V or -5+5V, configurable by jumpers
  • 4 x Gate channels, 0+5V, 0+7V or 0+10V, configurable by a jumper


  • optional MIDI IN LED, blinks when receiving MIDI events


  • optional GATE LED, lit when a note is on


  • MIDI IN connector


  • optional MIDI OUT connector, mirrors MIDI IN


  • hold down during power up to enter firmware update mode via MIDI
  • hold down while receiving a note to learn MIDI Channel (v2.03+)
  • hold down while receiving control change, after touch or program change to learn control CV parameter
  • hold down while moving pitch wheel up/down to turn note tuning mode on and off
  • hold down for 10 sec while the device is idle to reset the device to default settings

On-board switches

SW1-4 specify default base MIDI channel

  • MONO and DRUM modes use the base channel
  • DUAL mode uses base channel and base channel + 1
  • QUAD mode uses base channel, base channel +1, +2 and +3

1234 ch     1234 ch
.... 01     ...X 09
X... 02     X..X 10
.X.. 03     .X.X 11
XX.. 04     XX.X 12
..X. 05     ..XX 13
X.X. 06     X.XX 14
.XX. 07     .XXX 15
XXX. 08     XXXX 16

SW5-6 specify operation mode:

  • MONO
    CV: note, velocity, pitch bend, control
    Gate: gate, strobe, start, clock
  • DUAL
    CV: note, velocity, note2, velocity2
    Gate: gate, strobe, gate2, strobe2
  • QUAD
    CV: note, note2, note3, note4
    Gate: gate, gate2, gate3, gate4
  • DRUM
    CV: velocity, velocity2, velocity3, velocity4 pulses
    Gate: gate, gate2, gate3, gate4
56 Mode
.. mono
X. dual
.X quad
XX drum

Note CV: 1V/Oct pitch CV with optional micro tuning: every note can be set to output any CV level within selected output range. Can be used for Hz/V, alternate tuning schemes, or to correct VCO tracking imperfections. Note tuning is configured using special operation mode, and could be saved, restored or loaded via sysex message from a computer.

Velocity CV: linear by default, however, you can choose to adjust velocity response curve making it softer, harder or wider:


Control CV: by default, this CV tracks CC 1 (Modulation Wheel) value, however, it could be set to track any CC from 1 to 119, or after touch/program change values. If set to track after touch, the response curve could be adjusted similarly to velocity response curve. Control setting can be “learned” on the fly: hold down LEARN switch and turn/click the desired control knob/button, or press a key on after touch-enabled keyboard to track after touch.

Gate: goes high when a key is down, low when no keys are down. If “strobe gate” option is in effect, gate signal is pulled down for the duration of the strobe every time a key is pressed while some other key is down. This allows envelopes to re-trigger for synths that don’t have Strobe input.

Strobe: goes down for 1 to 5 ms, occurs each time a key is pressed. Strobe length and polarity are configurable by sending a sysex message and the setting is persisted in EEPROM.

Start: goes high when MIDI Start/Continue message is received and down when MIDI Stop message is received.

Clock: goes down for 1 to 5ms each time MIDI clock message is received, could be divided down to 32 triplet, 32th note, 16 triplet, 16th note, 8th note triplet, etc. all the way to 2 bar note. Division factor is configurable by a sysex and the setting is persisted in EEPROM.

In DRUM mode CV outputs produce gate like signals with amplitude proportional to the note velocity. The unit response to 4 predefined notes (by default C3,C3#,D3,D3#) on the base channel. The notes can be configured via sysex and are persisted in EEPROM.

MIDI Channel

On-board switches SW1-4 specify default MIDI channel. Midi2CV Mk2 uses this channel when it is first started or is reset to default settings. You can change Midi2CV Mk2 MIDI channel by changing these switches or “learning” it from a note played while holding down LEARN switch. The “learned” MIDI channel will be in effect until the device is reset, in which case the default MIDI Channel specified by DIP switches will be used.

LFO and EG

Starting with firmware version 2.0, Midi2CV Mk2 provides two extra modulation sources: LFO and AHDSR EG which can be assigned to any CV output. These modulation sources are controlled by MIDI CC commands sent from an external MIDI controller connected to MIDI IN.

LFO specifications:

  • frequency: 0.1-100Hz
  • shape: triangle, square, ramp up/down, S/H, random PWM, random lines, noise
  • free running or reset on note on
  • fade in 0 – 10sec
  • bipolar or unipolar
  • amplitude control

EG specifications:

  • segments: Attack, Hold, Decay, Sustain, Release
  • segment duration: 0-15sec
  • segment shape: linear, expo, sine
  • legato retrigger: on / off
  • MIDI Clock retrigger: 1/32T – 2bars
  • auto gate control – 0-15sec (similar to MS-20 EG)
  • looping: off, gated, auto
  • inverted: on/off
  • amplitude control

In looping mode EG can be used as a fancy LFO with the shape composed by four linear, exponential or sinusoidal segments with the duration specified by Attack, Hold, Decay, Sustain and Release controls.

Note CV tuning

The default note CV tuning is 1V/Oct for output range 0-10V and -5+5V ranges, and 0.5V/Oct for 0-5V range.

To enable note CV tuning mode, hold down LEARN switch and move Pitchbend wheel up, then release LEARN switch and return Pitchbend wheel to neutral.

To disable note CV tuning mode, hold down LEARN switch and move the Pitchbend wheel down, then release LEARN switch and return Pitchbend wheel to neutral.

While note tuning mode is in effect, hold done a note and use pitch wheel to adjust its pitch. Release the note to remember its pitch.

You can also use Control Change messages to reset, increment/decrement and interpolate note tuning, see the CC table below.

Control Change messages

LFO and AHDSR EG control CCs (v2.0+):

Parameter CC Description
LFO CV 90 0 – none
1 – CV1
2 – CV2
3 – CV3
4 – CV4
LFO Shape 91 0 – triangle
1 – square
2 – ramp up
3 – ramp down
4 – random S/H
5 – random Morse
6 – random lines
7 – noise
LFO Rate 92 0 – 127, 0.1 – 100Hertz
LFO Sync 93 (reserved, [TBI])
LFO Reset 94 0 – free running
1 – reset on note on
LFO Delay 95 0 – 127, 0 – 10sec
LFO Amplitude 96 0 – 127
LFO Bipolar 97 0 – unipolar
1 – bipolar
EG CV 100 0 – none
1 – CV1
2 – CV2
3 – CV3
4 – CV4
EG Attack 101 0 – 127, 0 – 15sec
EG Hold 102 0 – 127, 0 – 15sec
EG Decay 103 0 – 127, 0 – 15sec
EG Sustain 104 0 – 127
EG Release 105 0 – 127, 0 – 15sec
EG Gate 106 0 – 127, 0 – 15sec
EG Amplitude 107 0 – 127
EG Shape 108 0 – linear
1 – expo
2 – sine
EG Retrigger 109 0 – don’t retrigger on legato notes
1 – retrigger on every note on
EG Loop 110 0 – none
1 – loop while note is held down
2 – loop endlessly
EG Sync 111 Retrigger EG in sync with MIDI Clock
0 – none
1 – 1/32T
2 – 1/32
3 – 1/16T
4 – 1/16
5 – 1/8T
6 – 1/16D
7 – 1/8
8 – 1/4T
9 – 1/8D
10 – 1/4
11 – 1/2T
12 – 1/4D
13 – 1/2
14 – 1T
15 – 1/2D
16 – 1
17 – 2T
18 – 1 1/5
19 – 2
EG Invert 112 0 – normal
1 – inverted

While in note tuning mode Midi2CV Mk2 recognizes the following control messages:

CC Value Action
115 > 0 Reset all notes tuning
116 > 0 Reset last note tuning
117 > 0 Increment last note tuning
118 > 0 Decrement last note tuning
119 > 0 Interpolate last note tuning

You can also use pitch wheel to quickly get note tuning into required range.

Sysex data format

Sysex message format:

0xf0, // Sysex
0x29, // PPG manufacturer ID
'2','C','V',0x00, // Midi2CV Product ID
// * Command byte (SysexCmd)
// * Argument byte (flags | index)
// * Payload bytes (nibbelized)
0xf7 // Sysex end

Sysex message commands:

0x00, // arg=0 reset device, arg=1 update firmware (v1.14+)
0x01, // set controller cc number or 128=AT, 129=PC
0x02, // set strobe width 0-4: 1-5ms
0x03, // set clock divider 0-19: see intervals.h/cc
0x04, // set tune data 128 x int words of tune data
0x05, // set velocity curve, 0-8: linear, soft1/2/3, hard1/2/3, wide1/2
0x06, // set aftertouch curve, 0-8: linear, soft1/2/3, hard1/2/3, wide1/2
0x07, // set 4 x drum notes, 0-7f (v1.10+)

0x08, // set invert strobe mode: 0 - positive, 1 - negative (v1.11+)

0x09, // set invert gate mode: 0 - positive, 1 - negative (v1.12+)
0x0A, // set strobe gate mode: 0 - off, 1 - on (v1.13+)
0x10, // request firmware version (v1.11+)
0x11, // request SETCONTROLLER
0x12, // request SETSTROBEWIDTH
0x13, // request SETCLOCKDIVIDER
0x14, // request SETTUNEDATA
0x15, // request SETVELOCITYCURVE
0x17, // request SETDRUMNOTES (v1.10+)

0x18, // request SETINVERTEDSTROBE (v1.11+)
0x19, // request SETINVERTEDGATE (v1.12+)
0x1A, // request SETSTROBEGATE (v1.13+)

Firmware update

Midi2CV firmware update steps:

  1. Connect your MIDI interface output to Midi2CV MIDI IN
  2. Power on Midi2CV while holding down LEARN switch. LEDs will blink shortly then MIDI IN LED will stay steadily lit.
  3. Send firmware update sysex file (*.syx) to your MIDI interface port with 250ms delay between sysex buffers. Elektron’s C6 works great on OS X and Windows. Classic MIDI-OX is also good on Windows. MIDI LED will be blink while firmware sysex is being received. On successful update, LEDs will blink 3 times one after another. On error, both LEDs will blink together 5 times.

Starting with firmware version 1.14 you can request firmware update without using LEARN switch by sending RESET DEVICE sysex with argument byte set to 0x01. This facilitates firmware updates for applications where LEARN switch is not present or is difficult to access.

Revision history

v2.03 6/24/2017

  • Implemented MIDI Channel LEARN feature.

v2.02 5/23/2017

  • Fixed problem with clock output generating clock at incorrect frequency after receiving MIDI Stop followed by MIDI Continue events. Thanks to Benjamin for reporting.

v2.01 3/8/2017

  • Implemented more musical LFO fade in

v2.00 3/7/2017

  • Added LFO and EG

v1.14 1/10/2017

  • Set note CVs to C4 upon start or reset
  • Added ability to request firmware update by sysex

v1.13 11/3/2016

  • Added “strobe gate” option and sysex

v1.12 07/02/2015

  • Added gate polarity option and sysex

v1.11 06/17/2015

  • Fixed problems with All Notes Off handling
  • Added strobe polarity option and sysex
  • Added firmware version request sysex

v1.10 02/14/2015

  • added Drum Mode
  • changed Note Tuning mode activation to LEARN+PitchBend
  • fixed nasty EEEPROM initialization bug

DIY Resources

Bill of Materials: Midi2CV Mk2 BOM

Firmware: Midi2CV_Mk2_v203

Sysex files: midi2cv_mk2_sysex_114

Schematics: midi2cv_mk2

Firmware source code: Midi2CV_Mk2_203_src

Board outline (1:1 PDF): midi2cv_mk2


Ordering Midi2CV

To order Midi2CV, please send an email to pete at kvitek  c o m specifying how many PCBs and pre-programmed MCUs you need, a country where to ship them, and an email address to send the PayPal invoice to.

Prices (US dollars):

Midi2CV PCB — $25
Pre-programmed ATMega328p — $10


Continental USA — $5 (California residents add 8.75% tax)
Canada – $10
Europe – $15
Australia – $15

Please make sure your PayPal shipping address is correct!

Midi2CV_mk2#2 (small)

89 thoughts on “Midi2CV Mk2

  1. Pingback: Midi2CV Mk2 is available! | MidiSizer

      • It is for an 808 clone but with 16 voice boards!
        To make sound on 808 board you need 2 different voltages hit at the same time.
        One is for Trigger and it is 5v and the other is for Velocity and it is from +5v and max +15v.
        I need to control velocity for every step. So what i need is your module but with 32 outputs (16 CV & 16 Gates.)

        Best Regards

      • A bit tricky, but certainly doable: take 4 MIDI2CV Mk2s, run them in parallel in DRUM mode responding to different notes on the same MIDI channel split by MidiThru, build a simple divider to get -5V, and feed it to left side R14,R15,R27,R28.

  2. just my feedback : i’ve ordered that PCB 10 months ago and implemented it in a Arp2600 clone TTSH, and it works like a charm. The extreme versatility on CV range and SysEx programming is just amazing. An excellent midi2Cv project

  3. As long as you’ve already got a Midi out, it would be great if this project had the facility to input an analog clock to that Midi out. That way clock could go both ways in a modular synth application and midi clock could be master or slave to modular sequencers. I have seen some Midi2CV modules incorporating this feature lately, but none with 4-voice CV/gate unfortunately.

  4. Everything works great but I expected the clock in mono mode to be a square wave with rate = midi clock bpm. Instead I get a DC voltage proportional to the bpm.

    • Something is wrong with your build — you’re not supposed to have DC voltage at the digital output the clock signal is sent to!

      Clock output is rectangular pulses withe a duration equal to selected strobe width (1ms by default) and frequency determined by the incoming MIDI Clock divided by the selected Clock Division factor.

  5. Would it be possible to use the midi2cv to control three Korg Monotron synths in parallel? That is, sending an identical MIDI signal from an external sequencer, converting it to CV with this and then sending the same CV to all three units at the same time?
    If so, this looks like just what I was looking for!
    Thank you!

    • At this point I don’t offer full kits, only PCB and pre-programmed MCU. All other parts are jelly bin and can be ordered from DigiKey or Mouser, using published BOM.

  6. Hey 🙂
    Great project 🙂 i do have a question since im working on something where i wanna combine some stuff to make some cv modules into midi modules….. would it be possible to hack the firmware to get 5 cv 1 note and 2 gates instead of 4 cv and 4 gates?!

    Kind regards


  7. I’m have some issues with my build. I see constant voltage on Note, Strobe, and Bend outputs. Also, Midi In doesn’t seem to do anything. I’ve tried multiple midi controllers and keyboards. The midi led and gate led never illuminate. Any ideas?

    • 1. remove all the ICs and check all the voltages using the schematics. 2. insert MCU and check if it’s running by verifying that the LED blinks when you switch the power on. If LED is not blinking, check the XTAL pins to see if they have 20MHz sine signal on them. If not, look for shorts/connectivity etc around MCU.

  8. Hello,

    This is awesome an awesome project like your others project ! Congrats !
    If I already have midialf ( and a midirex) what would you recommend to have CV control : adding a CV extension or coupling the midialf with the midi2cv?

    From my point of view I ok say that the midi2cv will be more versatile. But is there a disadvantage using the midi2cv instead of midialf CV extension ?



    • It really depends on your requirements: if you need a stand alone MIDI/CV step sequencer that you can use with any MIDI or CV synth, MidiALF/CV is the better choice. If you have a modular system or an old synth which need to be MIDIfied, go with Midi2CV Mk2 and feed in notes from MIDI keyboard, MidiALF or MidiREX.

  9. I think I found a funny bug in V2.1. I am using a Beatstep Pro as a master clock. The MIDI2CV-mk2 responds correctly with start/stop control, it generates clock pulses as expected. However, when I use pause and resume the clock freaks out and generates clock pulses at what I assume is 300BPM.

    • Could not reproduce no matter what I tried, everything works as expected. In fact, Midi2CV Mk2 does not generate it’s own clock, it only incoming MIDI events into pulses, so there is no path that could generate clock on it’s own. 300 BPM is a maximum clock frequency BSP can generate, so it looks like the problem is on their side.

      • So let me further explain my current patch in which I noticed this supposed bug. I am running several sequences at once with the BSP as the master clock. I have the midi out of the BSP running into the midi in of the MIDI2CV-mk2. I then patch the midi thru of the MIDI2CV-mk2 over to a Mutable Instruments Yarns in which it utilizes the same clock signal. I am using the clock and start/stop signals from the MIDI2CV-mk2 to run a Klee sequencer. Everything syncs nice until I use the Pause(ll) button then resume again by hitting the Play(>) button. The clock pulse output from the MIDI2CV-mk2 goes haywire. I said in my earlier post that it defaults to 300BPM but this is just a guess. The midi thru is not effected by this erratic behavior, even while the MIDI2CV-mk2 is freaking out, the MI Yarns will stay synced. The “out of sync” MIDI2CV-mk2 can easily be tamed by pushing Stop and then Play. I have tried adjusting BSP transport control options but all lead back to this same problem. Anyhow, I love the module just though you might want to know about this problem.

  10. I have got a Crystal that is 20Mhz, but the Load Capacitance is 30pF…
    Will this work ok or do I need to change Capacitors C1 and C2 from 18pF.

    • It should work because both crystal and and capacitors have pretty large tolerance. However, if it doesn’t, you can always add a couple of 10pf caps in parallel on the bottom side of the PCB.

  11. Sorry, i’m still not clear with the jumper settings. My Keyboard (NEKTAR GX61) send MIDI signals only on the global Channel 1. I’ve configured the jumper of your board on Channel 1/ QUAD Mode. I expected the following behaviour: First Key appears on CV1, second Key on CV2 and so on. Nevertheless a voltage only appears on CV1. Pressing a second (higher) Key increases the voltage on CV1, but CV2-4 are dead anyway.

    • What you are expecting is called polyphonic mode which this device does not support. QUAD mode listens on 4 consecutive MIDI channels starting at the channel specified by the DIP switches 1-4.

    • You may want to try using MIDIpal or MidiGAL to dispatch your single channel MIDI controller output to 4 channels and send them all to Midi2CV Mk2.

      Also, I may decide to add Poly Mode for DUAL and QUAD setting in Midi2CV Mk2, however there are no plans to do this anytime soon.

      What exactly is your application?

    • Not really…. you can use MIDI Dispatcher to dispatch MIDI controller input to 4 MIDI Channels. Alternatively, you can use MIDI2CV Mk2 source code and add polyphonic void dispatcher from MIDIpal source code and build a customized firmware that does exactly what you need.

  12. Hey, i would like to control my xox heart with daw (ableton) Do you have a option for this. Can u build something like this? Sorry for lack of knowledge. Dont want to crash and burn my heart:-) Usb to cv etc.

  13. I build the unit from of the schematics and bill of materials, but its not working properly, midi in is responding, but got nothing on the gate outputs, also CV is only on 2 ports is constant 2.5 volts and on the other 2 ports no voltage, I am not sure if its an hardware issue as i am not sure how the software should be loaded and what settings to use as on different clocks the results are different like midi in only responding to some keys and not all. what are the settings for fuses in AVR studio? and there are 3 hex files, muboot.hex, midi2cv.hex and midi2cv_eeprom. do all files need to be loaded, and is there a specific order like load eprom first in eeprom loader, than muboot?

    • First of all, you have to make sure you programmed fuses correctly: -fD4FF -EFD, you can verify if this is the case by checking for 20MHz on XTAL inputs of the MCU. Then program midi2cv.hex only, this is enough for normal operation.

  14. Hi, I’m confused about the way Pitch Bend is implemented and would appreciate clarification. If I am using CV 1 (note) and move the pitch wheel on my controller keyboard, will it transfer that change through CV 1? Or does it count that as a totally separate controller and only send the pitch bend through CV 3 (in Mono mode)? Would that mean that pitch bending would have no effect at all in the other modes? The other MIDI-CV modules I’ve used in the past all sum the pitch bend with the main note CV, hence my confusion. Thanks for your help, this module looks fantastic!

  15. Hi!
    I’m looking for a MIDI 2 CV converter with at least 4 pitch/gate channels, and this Midi2cv-mk2 seems to fit those requirements, but I want to be sure. My idea is to use 4 MIDI tracks of an Elektron Octatrack (configured to a different MIDI channel each) to send 4 monophonic lines of notes with their respective gates to a modular synth. Would it be possible?
    I’m confident that I’d be able to build it with the PCB and the pre-programmed MCUs (I succesfully built a Befaco Rampage recently), but I’m by no means an expert in electronics. I’m guessing I just have to connect the CV outs to 4 1/8″ jack connectors, the Gate outs to another 4 1/8″ connectors and put the whole thing in a fancy box? My apologies if my question sounds stupid… 😛
    Thanks and keep up the good work!

    • Yeah, Midi2CV Mk2 will do exactly what you want in QUAD mode: receive MIDI events on four consecutive MIDI channels and output 4 x PitchCV and 4 x Gate signals.

  16. This looks like a perfect way to midi my Moog CDX. I could use one channel for the moog Satellite and one for the Moog bass. Perhaps this is a stupid question; but as the Satellite uses 2.5v per octave (-4.5 +4.5v) obviously the easiest way to setup the Midi2CV would be to use its learning mode. Am I to assume to do this I use a controller keyboard to play the midi ‘d moog and then use the pitch wheel on the controller to bend the note to the desired pitch? Will I need to do this on every note?, or just the upper and lower keys (and the rest will be the correctly calculated intervals)?

  17. Hi, my midi to cv has stopped working, when I connect it the two leds flashes 3 times and one of them keeps on after that.
    When a midi note enters the led turns off and no other signal until I restart it.
    How can I reprogram it?
    Thanks in advance

      • It’s the same even with no button or with the 14 pin lifted from the socket, three alternative flashes each and then led 1 on till I press a key, then nothing.
        When the atmega is plugged there is continuity between the switch pins (with no switch plugged).

      • Check if continuity is there with microcontroller IC removed and if so, fix the short. If there is no continuity with no IC, try sending the firmware sysex to see if it will re-programm itself.

  18. There is no continuity with the microcontroller IC removed, the sysex message has no answer, maybe I could try to reprogram it, I have an usbasp but not very confident on how to use it.

    • Strange… sure, you can try to reprogram it — firmware in hex and syx formats are available on this web site. I’m not familiar with usbasp at all.

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