ER-MIDI-CV4-02
Contents
Features
- Eurorack 6HP, 3U module
- Three card stack-up
- Front Panel card
- Controls card
- 9 Jacks, 1 pot
- Processor card
- Arduino Pro Mini
- 16 MHz
- 5V
- MIDI In
- TRS Type A jack MIDI In
- USB MIDI In if external FTDI card/cable
- (4) 0-4.096V Analog CV outs
- MCP4822 12-bit D/A - SPI Interface
- D/A has built in output opamps, set gain to 2X
- Outputs may only swing 2x 2.048V or 4.096V (4 octaves)
- GATE output (0-5V)
- CLK output (0-5V)
- TRIG output (0-5V)
- Standard Eurorack 16 pin power header
Credits
- Adapted from HAGIWO's MIDI to CV module
- Translate from Japanese to English using browser
- Has 4 Analog Outputs instead of 2
- Arduino Pro Mini instead of Arduino NANO
- Based also on SYNTH-MIDI-CTL-01
Arduino Pins
- Arduino Pro Mini
- Analog 1 - Speed Adjust POT
- A4 = SDA
- A5 = SCL
- D8 = LDAC1* to CV_1, CV2
- D9 = LDAC2* to CV_3, CV_4
- D13 = SPI CSK to both ADCs
- D11 = SPI MOSI to both ADCs
- D10 = SLAVE SELECT to both ADCs
Connection to FTDI
- Use FTDI-49MM card
- Right angle 1x6 pins
- Pinout
- GND
- CTSn (IN)
- VCC
- TX (OUT)
- RX (IN)
- RTSn (OUT)
- Arduino Pro Mini Serial Connector
- Marking matches FTDI cable pinouts/color codes
- BLK
- GND
- VCC
- RX
- TX
- GRN
Connectors
Processing Card Connectors
J1 - Eurorack Power
- 2x5 IDC connector
- Only uses +12V (and GND)
- Diode polarity protected, series resistor
J2 - CVs, GATE, CLK (to/from Controls card)
- J12 on Controls card
- Pinout
- VCC (+5V)
- GATE
- CLK
- CV4
- CV2
- POT
- CV1
- CV3
- TRIGGER
- GND
J3 - I2C
- Pinout
- SCL
- SDA
- VCC (+5V)
- GND
J4 - MIDI (to/from Controls card)
- J9 on Controls card
- Pinout
- VCC (+5V)
- MIDI Out
- MIDI In
- GND
J5 - MIDI into RX
- Remove to use MIDI from Controls card
J6 - MIDI OUT/THRU Select
- 1-2 = MIDI Thru
- 2-3 = MIDI out from Arduino TX
Controls Card Connectors
J1 - CLK
- MIDI Clock out
- 0-5V, Digital
J2 - CV1 Out
- Control Voltage out
- 0-5V Analog Clock
J3 - CV2 Out
- Control Voltage out
- 0-5V Analog Clock
J4 - CV3 Out
- Control Voltage out
- 0-5V Analog Clock
J5 - CV4 Out
- Control Voltage out
- 0-5V Analog Clock
J6 - TRIGGER
- MIDI Trigger out
- 0-5V, Digital
J7 - GATE
- MIDI Gate out
- 0-5V, Digital
J8 - MIDI In
- MIDI Input
- TRS Type A
J9 - MIDI Out
- MIDI Output
- TRS Type A
J10 - CVs, GATE, CLK, TRIG
J11 - MIDI
Application
- Use with ER-VCO-03 to control pitch and Mod
- CV_1 = V/OCT
- CV_2 = MOD
- Use GATE output into ER-ADSR-555-01 output of ADSR to MOD input of ER-VCA2-01 to control amplitude
- Arduino MIDI Library
- MIDI Notes
Download steps
- Unplug MIDI in cable from front panel
- Connect FTDI card with 1:1 cable
- Download code in Arduino IDE
- Disconnect FTDI
- Connect MIDI in cable to front panel
Card Test Code
- TestPotDigIOs - Test Digital Outputs (CLK, TRIG, GATE) and Speed Pot
- ER_MIDI_CV4_04_TEST_DACs - Read pot, scale value. write to 4 analog outputs. Also, drive CLK, TRIG, GATE digital outputs
HAGIWO code baseline
- SYNTHMIDICTL01.ino
- Runs on Arduino ATMEGA328 (Arduino NANO or Pro Mini)
- Used as baseline and converted to CircuitPython
Working Code
- ER_MIDI_CV4_02 - Working code
// V/OCT LSB for DAC // ER-VCO-03 characteristics // PITCH ADJ knob roughly centered // 0V = 93.08 Hz (roughly F2) // 1V = 179 Hz (G3) // 1.52V = 261 Hz (C4) // 2V = 365 Hz (G4) // 3V = 722 Hz (G5) // 4V = 1.45 KHz (G6) // 5V = 3.05 KHz (G7) // Max output voltage of this card is 4.096V (4 octaves) // 1mV per DAC count // 12 notes per octave = 1/12V per note = 83.333 mV // Steps are in 83.333 mV // Table counts up by integer steps - rounded 83.333 mV
3D Views
- Controls card side view
- Processing card side view
Videos
- HAGIWO MIDI to CV module
- Midi2CV - A utility module for converting MIDI messages to CV] Benjie Jiao - DIY Modular Synth Project_
Issues
Rev 2
- Daughtercard
- Fixed missing connection D14 anode to GND
- Moved R1 down a bit
- Haven't ordered yet (2022-12-04)
Rev 1
- Daughtercard
- Missing connection D14 anode to GND
- Add wire D14-Anode to D9-Anode
- R1 is close to Arduino socket (fit OK, but tight)
- Missing connection D14 anode to GND
