Planning Your Project with EZ MIDI 2

Version 2.0.0

Before starting, consider the capabilities and limitations of EZ MIDI 2.
This board serves as both the brain for your effect pedal and a programming interface via a web-based MIDI editor.

Supported Operation Modes (v2.0.0):

  • Control Voltage Array (for overdrives/fuzzes, switching, etc.)

  • Warp LFO

  • Non-Warp LFO

Coming soon: PT2399, BBD, and PWM Synthesizer modes.

Inputs

  • Pots 1–6: Assignable in the web editor.

  • Pot 7: Used for mode-specific selection (e.g., row selection in CV Array).

  • Pot 8: Preset selection.

  • Signal Input: For envelope-based modulation. Use a 1.65V-biased input signal.

  • SW1: Momentary switch for bypass.

  • SW2: Tap tempo switch (LFO modes).

  • MIDI Input: Full control of all parameters.

Outputs

  • Up to 7 PWM/Control Voltage outputs (3.3V @ 62.5kHz PWM).

  • Up to 3 MCP42xxx digital pots (daisy-chained).

  • 2 Bypass Control Pins (relay or analog).

  • 1 Bypass LED Pin

  • OLED Display (used by the programmer board only).

Using the Programmer Board

To configure your effect:

  1. Insert a 24LC32 EEPROM into EEPROM 3 socket on the programmer board.

  2. Power with a 9V supply and connect via MIDI.

  3. Open the EZ MIDI Web Editor and go through each tab.

  4. Click Send All MIDI Data when done. MIDI CC messages will be shown in the history.

  5. Press SW1 on the programmer board to save settings.

If you’re not using the programmer board, refer to the schematic and use an STM32F103C8 (“Blue Pill”) with the demo firmware (runs full-featured for about 90 minutes).

Control Voltage (PWM) Mapping

PWM outputs default to 3.3V pulse waves (62.5kHz). Use an RC filter to convert to analog CV if needed.

  • Any PWM/CV output can follow Pot 1–6 or the LFO.

  • Assignments are fully manual — there’s no automatic validation.

  • You can assign the same source to multiple pins or assign outputs even if the mode isn’t active.

Digital Pot Mapping (MCP42xxx)

  • Use 1–3 MCP42xxx ICs in a daisy chain.

  • EZ MIDI doesn’t check if pots are connected — you can assign all 3 even if only 1 is present.

Control Voltage Array Mode

  • Use Pot 7 to select a row from a stored array of CV values.

  • Map columns to PWM outputs to control analog switches, tone-shaping circuits, etc.

Next Steps

Use this info to plan how your pedal will function and how users will control it.
Then, configure it using the EZ MIDI Web Editor and programmer board or your own STM32 setup.