INTRODUCTION
A Eurorack compatible USB MIDI to CV converter using the Teensy 3.1
microcontroller as its USB port and controller. The 6HP wide unit includes
2 CV channels, 2 gate channels, an isolated DIN MIDI input connector
and a DIN MIDI output connector.
When the module is sent from the factory, a simple operating sketch is
loaded that will permit the module to be recognized by an attached
computer as a USD MIDI device. MIDI note commands sent to the module
are echoed on the MIDI OUT DIN connector and valid MIDI note values
are converted to analog CV values on the CV output connectors. An
accompanying GATE signal is produced. When the MIDI note on value is
received the GATE output goes high (+5 VDC). When the MIDI note off
value is received, the GATE output goes low (O VDC).
When a valid MIDI note command is received on the MIDI IN DIN connector, it is converted to an analog
CV output value along with a accompanying GATE output. The MIDI note command is also sent to the
USB MIDI connector and to a connected computer. The MIDI IN DIN to analog CV output will operated
without an external computer connected so the module can be used as a standalone MIDI to CV
converter.
The source for the current factory installed program can be downloaded from the Grove Audio website.
Users with an Arduino IDE with Teensyduino extensions can customize this program to their own needs.
See appendix B for information regarding installing HEX image updates as well as instructions on how to
obtain and setup the Arduino development environment.
The control voltage output range is internally settable to 0-10 Volts or -5-+5 Volts. The gate signal is 0-5
Volts active-high. The software for the unit is open-source and can be reloaded and modified by the user.
A programming development environment that utilizes the Arduino IDE with a Teensy support add-in can
be used to create new functions using Arduino-like commands.
The Teensy 3.1 is a powerful microprocessor card containing a 72MHz Freescale MK20DX256 Cortex-
M4 processor and USB communications processor on a 3/4 inch by 1 1/3 inch PC board. It has 256KB of
program memory and 64KB of RAM. There is a Teensyduino add-in available for the Arduino IDE that
allow sketches developed in the Arduino enviroment to be loaded into the Teensy.
