MorphaLogic

An Eurorack module based around a Arduino Nano.

With AND, OR, XOR logic functions, a Flip Flip (Q), a Clock Divider mode, and more.

<img src="pictures/FRONT PANEL.png" alt="Morgalogic Front Panel" height="400px">

Inputs, Outputs & Buttons

<table> <tr> <td><b>LEFT</b></td><td style="text-align: right;"><b>RIGHT</b></td> <tr><td>INPUT: input (A)</td><td style="text-align: right;">OUTPUT: AND (or clock / 16)</td></tr> <tr><td>INPUT: input (B)</td><td style="text-align: right;">OUTPUT: OR (or clock / 8)</td></tr> <tr><td>INPUT: Inverse (INV)</td><td style="text-align: right;">OUTPUT: XOR (or clock / 4)</td></tr> <tr><td>INPUT: Clock (CLK)</td><td style="text-align: right;">OUTPUT: Q - Flip Flop (or clock / 2)</td></tr> <tr><td>OUTPUT: Inverse of TRIG BUTTON</td><td style="text-align: right;">Trigger on press & release of TRIG BUTTON</td></tr> <tr><td>BUTTON: Mode button</td><td style="text-align: right;">BUTTON: Reset button</td></tr> <tr><td colspan="2" style="text-align: center;">TRIG BUTTON</td></tr> </tr> </table>

Functions

Logic functions

• Basic logic funcions AND, OR, XOR (using the first inputs on the left side).
• Flip Flop (Q) (first input will SET, second input will RESET).
• NOT input, or MODE button, to inverse all logic outputs (NAND, NOR, NXOR, NQ)
• CLOCK input, when present, all Logic outputs only are HIGH when CLOCK is HIGH
• RESET button to reset Q and CLOCK

Trig button

When the TRIG button is pressed (and released):

• A LOW gate is send to the first (left) output. It will be HIGH when the button is not pressed.
• A short pulse is send to the second output on press & release of the button.
• If the module is in Clock Divider mode, the press & release time will set the Clock Tempe if no signal is present on the CLOCK input.

Modes:

Current mode is set in memory.

Normal mode (mode button is unlit):

• Inputs A & B determines logic outputs (AND, OR, XOR, Q). Where A is set and B is reset for the flipflop (Q).
• If the NOT input is HIGH, all logic outputs are inverted (NAND, NOR, NXOR,NQ)

Inverse mode (mode button is lit):

• Pressing the mode button will inverse all logic outputs (same as when NOT input is HIGH)

Clockdivider mode (mode button is flashing):

• A long press on the mode button will put the module in Clockdivider mode. The mode button will flash.
• The logic outputs will divide the clock (where Q = /2, XOR = /4, OR = /8, AND =/16)
• The clock source is:
  • The CLK input
  • If no clock is present on the CLK input, a standard 120 BPM clock is used.
  • Or, if the trig buttons has been pressed and released, the timing between press and release is used to determine the clock time.

External Trig Mode (trig button flashes):

• A long press of the RESET button toggles between external trig options mode on/off. When on, the trig button flashes.
• When external trig mode is on, the first input can function as an external trig for the trig button.

Uses

• Use the logic function for all kinds of GATE manipluations, for interesting sequences for example.
• Same for the CLOCK DIVIDER mode.
• Make use of the CLOCK input to quantize the logic outputs with a clock signal.
• Use the TRIG BUTTON (or external trig mode) for changing a GATE into two short TRIGS.
• Use the TRIG BUTTON to fire a LOW gate (patch it into one of the logic function to have a HIGH gate on the OR output).

Example with a Morphagene

One of my main modules in my eurorack case is the Make-Noise Morphagene. One thing that i'd like it to do is:

• Press and hold button to record - currently playing loop is stopped, and recording is started.
• Release button - recording is stopped and starts playing.

To make this work:

• Prepare the Morphagene by setting the Record option (rsop) in the options.txt file on the SD card to '1'.
• Patch the TRIGGER output of the TRIG BUTTON to the RECORD input of the Morphagene
• Patch the INVERSE output of the TRIG BUTTOON to the PLAY input of the Morphagene

Now:

• When pressing (and holding) the TRIG BUTTON the Morphagene start recording (and stops playing).
• When releasing the TRIG BUTTON the Morphagene stops recording and starts playing.
• If in Clock Divider mode and no Clock signal is present at the CLOCK input, the tempo is set to the time between pressing and releasing the button.

Content:

In this repo you'll find:

• Arduino program
• Schematics
• BOM
• KiCad project with schematics & PCB & FrontPanel PCB
• STL file for printing the buttons
• Several pictures

Buying a kit

If you'd like to build this module you can buy a kit with:

• PCB
• Frontpanel
• 3D printed buttons

Contact me if you are interested.

By Jan den Besten <a href="https://www.jandenbesten.com">www.jandenbesten.com</a>