View source for ER-MIDI-CV4-02

[[FILE:ER-USB-MIDI-CV4-01_SET_FRONT_REAR_3D-720PX.png]]

== Features ==

* Eurorack 6HP, 3U module
* Three card stack-up
** Front Panel card
** Controls card
*** 8 Jacks, 1 pot
** Processor card
* [[Arduino_Pro_Mini|Arduino Pro Mini]]
** 16 MHz
** 5V
* MIDI In
** TRS Type A jack MIDI In
** USB MIDI In if external FTDI card/cable
* (4) 0-5V Analog CV outs
** [https://www.mouser.com/ProductDetail/Microchip-Technology-Atmel/MCP4822-E-P?qs=sGAEpiMZZMtgJDuTUz7Xu5a0A%252BlHhkxt3QSpqvc4zyk%3D MCP4822 12-bit D/A] - SPI Interface
*** [https://www.mouser.com/datasheet/2/268/21953a-8929.pdf MCP4822 Datasheet]
** 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
* Standard Eurorack 16 pin power header

=== Credits ===

* Adapted from [https://note.com/solder_state/n/n17e028497eba 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

[[file:ArdruinoProMini-EBAY_PART-720px.png]]

==== 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

[[file:FTDI_Cable_Color_Code.png]]

# BLK
# GND
# VCC
# RX
# TX
# GRN

== Connectors ==

=== Processing Card Connectors ===

==== J1 - Eurorack Power ====

[[file:ER-MIDI-CV4-02_DB_J1.PNG]]

* 2x5 IDC connector
* Only uses +12V (and GND)
* Diode polarity protected, series resistor

==== J2 - CVs, GATE, CLK (to/from Controls card) ====

[[file:ER-MIDI-CV4-02_DB_J2.PNG]]

* J12 on Controls card
* Pinout

# VCC (+5V)
# GATE
# CLK
# CV4
# CV2
# POT
# CV1
# CV3
# TRIGGER
# GND

==== J3 - I2C ====

[[file:ER-MIDI-CV4-02_DB_J3.PNG]]

* Pinout

# SCL
# SDA
# VCC (+5V)
# GND

==== J4 - MIDI (to/from Controls card) ====

[[file:ER-MIDI-CV4-02_DB_J4.PNG]]

* J9 on Controls card
* Pinout

# VCC (+5V)
# MIDI Out
# MIDI In
# GND

==== J5 - MIDI into RX ====

[[file:ER-MIDI-CV4-02_DB_J5.PNG]]

* Remove to use MIDI from Controls card

==== J6 - MIDI OUT/THRU Select ====

[[FILE:ER-MIDI-CV4-02_DB_J6.PNG]]

* 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 ====

[[FILE:ER-MIDI-CV4-CTLS_J10.PNG]]

==== J11 - MIDI ====

[[FILE:ER-MIDI-CV4-CTLS_J11.PNG]]

== 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
* [http://fortyseveneffects.github.io/arduino_midi_library/ Arduino MIDI Library]
* [https://www.inspiredacoustics.com/en/MIDI_note_numbers_and_center_frequencies 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 ===

* [https://github.com/land-boards/lb-Arduino-Code/blob/master/LBCards/SYNTHS/ER_MIDI_CV/TestPotDigIOs/TestPotDigIOs.ino TestPotDigIOs] - Test Digital Outputs (CLK, TRIG, GATE) and Speed Pot
* [https://github.com/land-boards/lb-Arduino-Code/blob/master/LBCards/SYNTHS/ER_MIDI_CV/ER_MIDI_CV4_04_TEST_DACs/ER_MIDI_CV4_04_TEST_DACs.ino 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 ===

* [https://github.com/land-boards/lb-Arduino-Code/blob/master/LBCards/SYNTHS/ER_MIDI_CV/SYNTHMIDICTL01/SYNTHMIDICTL01.ino SYNTHMIDICTL01.ino]
** Runs on Arduino ATMEGA328 (Arduino NANO or Pro Mini)
** Used as baseline and converted to CircuitPython

=== Working Code ===

* [https://github.com/land-boards/lb-Arduino-Code/blob/master/LBCards/SYNTHS/ER_MIDI_CV/ER_MIDI_CV4_02/ER_MIDI_CV4_02.ino ER_MIDI_CV4_02] - Working code

<pre>
// 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
</pre>

== 3D Views ==

* Controls card side view

[[file:ER-MIDI-CV4-02_CTLS_SIDE-3D.png]]

* Processing card side view

[[FILE:ER-MIDI-CV4-02_DB_SIDE_3D.png]]

== Videos ==

* HAGIWO MIDI to CV module

<video type="youtube">bHiZhLAntNI</video>

* Midi2CV - A utility module for converting MIDI messages to CV] Benjie Jiao - DIY Modular Synth Project_

<video type="youtube">fez_pjEC9eA</video>

== Issues ==

=== 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)
*** Moved down a bit

== Assembly Sheet ==

* [[ER-MIDI-CV4-02 Rev 1 Assembly Sheet]]