# MIDI Footswitch 

AVR-based footswitch controller for MIDI appliances.

The current implementation supports 4 pushbuttons and 1 toggle switch (usually bank switcher) and a hard-coded range of MIDI sequences.
Hardware os based on a single ATtiny2313 microprocessor.

Original design indended to retrofit an analog Vox VFS5 footswitch to control am Axe-Fx II effect processor by Fractal Audio Systems.

## Hardware Specs

Hardware is designed to work with a power supply of 7 to 25V DC which is suitable for a standard 9V DC power supply or battery which is common for effect pedals.

The logic is powerd by a Atmel/Microchip ATtiny2313 processor, which can be swapped with about any AVR controller proividing 8 I/O ports and a USART interface.
MIDI signal is directly connected to the USART output (active low) of the controller and the 5V DC supply of the board through two 220 Ohm resistors.

| Pin on Controller | Pin on MIDI Jack | Function               |
|:-----------------:|:----------------:|:----------------------:|
| X5.1              | 2                | Ground                 |
| X5.2              | 5                | Signal through 220 Ohm |
| X5.3              | 4                | +5V through 220 Ohm    |


The provided layout is perfboard compatible with a more or less minimal layout to fit into the footswitch casing without removing the original PCB.


## Footswitch Layout and transmitted MIDI codes


| Label          | BANK                | CH1 | CH2 | CH3 | CH4 (Tuner) |
|:--------------:|:-------------------:|:---:|:---:|:---:|:-----------:|
| **LED**        | ⭕ (1 green, 2 red) | -   | -   | -   | -           |
| **Button**     | ⭗                  | ⭗   | ⭗  | ⭗  | ⭗          |
| **MIDI Codes** | Bank 1: 0xB0 0x00 0x00 0xC0 0x00<br>Bank 2: 0xB0 0x00 0x01 0xC0 0x00 | 0xC0 0x00 | 0xC0 0x01 | 0xC0 0x02 | 0xB0 0x0F 0x7F |

As documented, the _CH4_ Button does not enable Channel 4 as expected, but sets the effect processor into tuner mode (which bypasses the output, so implicit mute).
Thus you effectively control 3 channels on each bank 1 and bank 2.

The LED is green for Bank 1 and red for Bank 2. When in tuner mode the LED flashes in the current color with a frequency of about 2 Hz.


## License

The project is licensed under [GPL v3](https://www.gnu.org/licenses/gpl-3.0.de.html) license.