MiniDexed/README.md

# MiniDexed ![](https://github.com/probonopd/MiniDexed/actions/workflows/build.yml/badge.svg)

![minidexed](https://user-images.githubusercontent.com/2480569/161813414-bb156a1c-efec-44c0-802a-8926412a08e0.jpg)

MiniDexed is a FM synthesizer closely modeled on the famous DX7 by a well-known Japanese manufacturer running on a bare metal Raspberry Pi (without a Linux kernel or operating system). On Raspberry Pi 2 and larger, it can run 8 tone generators, not unlike the TX816/TX802 (8 DX7 instances without the keyboard in one box). [Featured on HACKADAY](https://hackaday.com/2022/04/19/bare-metal-gives-this-pi-some-classic-synths/).

## Features

- [x] Uses [Synth_Dexed](https://codeberg.org/dcoredump/Synth_Dexed) with [circle-stdlib](https://github.com/smuehlst/circle-stdlib)
- [x] SD card contents can be downloaded from [GitHub Releases](../../releases)
- [x] Runs on Raspberry Pi Zero, Raspberry Pi 1, 2, 3, 4, 400
- [x] produces sound on the headphone jack, HDMI (better), or a dedicated DAC (best)
- [x] Supports multiple voices through Program Change and Bank Change LSB/MSB MIDI messages
- [x] Loads `.syx` files from SD card (e.g., using `getsysex.sh` or from [Dexed_cart_1.0.zip](http://hsjp.eu/downloads/Dexed/Dexed_cart_1.0.zip))
- [x] Menu structure on optional [HD44780 display](https://www.berrybase.de/sensoren-module/displays/alphanumerische-displays/alphanumerisches-lcd-16x2-gr-252-n/gelb) and rotary encoder
- [x] Runs up to 8 Dexed instances simultaneously (like in a TX816) and mixes their output together
- [x] Allows for each Dexed instance to be detuned and stereo shifted
- [x] Allows to configure multiple Dexed instances through `performance.ini` files
- [x] Compressor effect
- [x] Reverb effect

TODO

- [ ] Make it possible to assign voice parameters to sliders and knobs on MIDI controllers
- [ ] https://github.com/probonopd/MiniDexed/issues

## Introduction

Video about this project by [Floyd Steinberg](https://www.youtube.com/watch?v=Z3t94ceMHJo):

[![](https://i.ytimg.com/vi/Z3t94ceMHJo/sddefault.jpg)](https://www.youtube.com/watch?v=Z3t94ceMHJo)

## System Requirements

* Raspberry Pi 1, 2, 3, 4, or 400 (Zero and Zero 2 can be used but need HDMI or a supported i2s DAC for audio out). On Raspberry Pi 1 and on Raspberry Pi Zero there will be severely limited functionality (only one tone generator instead of 8)
* A PCM5102A or PCM5122 based DAC or HDMI display or audio extractor for good sound quality. If you don't have this, you can use the headphone jack on the Raspberry Pi but on anything but the Raspberry 4 the sound quality will be seriously limited
* Optionally (but highly recommended), an [alphanumeric 1602 LCD Display](https://www.berrybase.de/en/sensors-modules/displays/alphanumeric-displays/alphanumerisches-lcd-16x2-gr-252-n/gelb) and a [KY-040 rotary encoder](https://www.berrybase.de/en/components/passive-components/potentiometer/rotary-encoder/drehregler/rotary-encoder-mit-breakoutboard-ohne-gewinde-und-mutter)

## Usage

* In the case of Raspberry Pi 4, Update the firmware and bootloader to the latest version (not doing this may cause USB reliability issues)
* Download from [GitHub Releases](../../releases)
* Unzip
* Put the files into the root directory of a FAT32 formatted partition on SD/microSD card
* Put SD/microSD card into Raspberry Pi 1, 2, 3 or 4, or 400 (Zero and Zero 2 can be used but need HDMI or a supported i2c DAC for audio out)
* Attach headphones to the headphone jack using `SoundDevice=pwm` in `minidexed.ini` (default) (poor audio quality)
* Alternatively, attach a  PCM5102A or PCM5122 based DAC and select i2c sound output using `SoundDevice=i2s` in `minidexed.ini` (best audio quality)
* Alternatively, attach a HDMI display with sound and select HDMI sound output using `SoundDevice=hdmi` in `minidexed.ini` (this may introduce slight latency)
* Attach a MIDI keyboard via USB
* Boot
* Start playing
* See the Wiki for [Menu](https://github.com/probonopd/MiniDexed/wiki/Menu) operation


## Pinout

All devices on Raspberry Pi GPIOs are **optional**.

__CAUTION:__ All GPIO numbers are [chip numbers](https://pinout.xyz/), not header positions.

|GPIO | Device |  | Function | Direction | Comment|
|---|---|---|---|---|---|
|14 | UART |  | TXD |  | OUT |  | serial MIDI|
|15 | UART |  | RXD |  | IN |  | serial MIDI|
|18 | DAC |  | CLK |  | OUT|
|19 | DAC |  | FS |  | OUT|
|21 | DAC |  | DOUT |  | OUT|
|02 | I2C |  | SDA |  | IN/OUT |  | used by some DACs|
|03 | I2C |  | SCL |  | OUT |  | used by some DACs|
|17 | LCD |  | EN |  | OUT |  | default setting|
|27 | LCD |  | RS |  | OUT |  | default setting|
|16 | LCD |  | RW |  | OUT |  | default setting, optional|
|22 | LCD |  | D4 |  | OUT |  | default setting|
|23 | LCD |  | D5 |  | OUT |  | default setting|
|24 | LCD |  | D6 |  | OUT |  | default setting|
|25 | LCD |  | D7 |  | OUT |  | default setting|
|05 | ROTARY ENCODER | CLK (ENC A) | IN |  | default setting|
|06 | ROTARY ENCODER | DT (ENC B) | IN |  | default setting|
|26 | ROTARY ENCODER | SW |  | IN |  | default setting|
|12 | PWM AUDIO | PWM0 |  | OUT |  | on Raspberry Pi Zero|
|13 | PWM AUDIO | PWM1 |  | OUT |  | on Raspberry Pi Zero|
|07 | SPI |  | /CE1 |  | OUT |  | reserved|
|08 | SPI |  | /CE0 |  | OUT |  | reserved|
|09 | SPI |  | MISO |  | IN |  | reserved|
|10 | SPI |  | MOSI |  | OUT |  | reserved|
|11 | SPI |  | SCLK |  | OUT |  | reserved|
|04 | NONE |  |  |  |  |  | can generate clock signal|
|20 | NONE |  |  |  |  |  | may be used for DAC DIN|

## Downloading

Compiled versions are available on [GitHub Releases](../../releases). Just download and put on a FAT32 formatted SD card.

# Building

Please see the [wiki](https://github.com/probonopd/MiniDexed/wiki/Development#building-locally) on how to compile the code yourself.

## Discussions

https://github.com/probonopd/MiniDexed/discussions

## Documentation

https://github.com/probonopd/MiniDexed/wiki

## Acknowledgements

This project stands on the shoulders of giants. Special thanks to:

* [raphlinus](https://github.com/raphlinus) for the [MSFA](https://github.com/google/music-synthesizer-for-android) sound engine
* [asb2m10](https://github.com/asb2m10/dexed) for the [Dexed](https://github.com/asb2m10/dexed) software
* [dcoredump](https://github.com/dcoredump) for https://codeberg.org/dcoredump/Synth_Dexed, a port of Dexed for embedded systems
* [rsta2](https://github.com/rsta2) for https://github.com/rsta2/circle, the library to run code on bare metal Raspberry Pi (without a Linux kernel or operating system) and for the bulk of the MiniDexed code 
* [smuehlst](https://github.com/smuehlst) for https://github.com/smuehlst/circle-stdlib, a version with Standard C and C++ library support
Add badge [ci skip] 3 years ago			`# MiniDexed ![](https://github.com/probonopd/MiniDexed/actions/workflows/build.yml/badge.svg)`
Update README.md [ci skip] 3 years ago
Add picture [ci skip] 3 years ago			`![minidexed](https://user-images.githubusercontent.com/2480569/161813414-bb156a1c-efec-44c0-802a-8926412a08e0.jpg)`
Add LCD screenshot [ci skip] 3 years ago
HACKADAY [ci skip] 3 years ago			`MiniDexed is a FM synthesizer closely modeled on the famous DX7 by a well-known Japanese manufacturer running on a bare metal Raspberry Pi (without a Linux kernel or operating system). On Raspberry Pi 2 and larger, it can run 8 tone generators, not unlike the TX816/TX802 (8 DX7 instances without the keyboard in one box). [Featured on HACKADAY](https://hackaday.com/2022/04/19/bare-metal-gives-this-pi-some-classic-synths/).`
Update README.md [ci skip] 3 years ago
Update description [ci skip] 3 years ago			`## Features`
Update README.md [ci skip] 3 years ago
Update README.md (#100) [ci skip] 3 years ago			`- [x] Uses [Synth_Dexed](https://codeberg.org/dcoredump/Synth_Dexed) with [circle-stdlib](https://github.com/smuehlst/circle-stdlib)`
			`- [x] SD card contents can be downloaded from [GitHub Releases](../../releases)`
			`- [x] Runs on Raspberry Pi Zero, Raspberry Pi 1, 2, 3, 4, 400`
			`- [x] produces sound on the headphone jack, HDMI (better), or a dedicated DAC (best)`
			`- [x] Supports multiple voices through Program Change and Bank Change LSB/MSB MIDI messages`
			- [x] Loads `.syx` files from SD card (e.g., using `getsysex.sh` or from [Dexed_cart_1.0.zip](http://hsjp.eu/downloads/Dexed/Dexed_cart_1.0.zip))
			`- [x] Menu structure on optional [HD44780 display](https://www.berrybase.de/sensoren-module/displays/alphanumerische-displays/alphanumerisches-lcd-16x2-gr-252-n/gelb) and rotary encoder`
			`- [x] Runs up to 8 Dexed instances simultaneously (like in a TX816) and mixes their output together`
			`- [x] Allows for each Dexed instance to be detuned and stereo shifted`
			- [x] Allows to configure multiple Dexed instances through `performance.ini` files
			`- [x] Compressor effect`
			`- [x] Reverb effect`

			`TODO`

Update README.md 3 years ago			`- [ ] Make it possible to assign voice parameters to sliders and knobs on MIDI controllers`
Update README.md (#100) [ci skip] 3 years ago			`- [ ] https://github.com/probonopd/MiniDexed/issues`
Update README.md [ci skip] 3 years ago
Add video, discussions and Wiki [ci skip] 3 years ago			`## Introduction`

			`Video about this project by [Floyd Steinberg](https://www.youtube.com/watch?v=Z3t94ceMHJo):`

			`[![](https://i.ytimg.com/vi/Z3t94ceMHJo/sddefault.jpg)](https://www.youtube.com/watch?v=Z3t94ceMHJo)`

System Requirements 3 years ago			`## System Requirements`

Fix typo [ci skip] 3 years ago			`* Raspberry Pi 1, 2, 3, 4, or 400 (Zero and Zero 2 can be used but need HDMI or a supported i2s DAC for audio out). On Raspberry Pi 1 and on Raspberry Pi Zero there will be severely limited functionality (only one tone generator instead of 8)`
System Requirements 3 years ago			`* A PCM5102A or PCM5122 based DAC or HDMI display or audio extractor for good sound quality. If you don't have this, you can use the headphone jack on the Raspberry Pi but on anything but the Raspberry 4 the sound quality will be seriously limited`
			`* Optionally (but highly recommended), an [alphanumeric 1602 LCD Display](https://www.berrybase.de/en/sensors-modules/displays/alphanumeric-displays/alphanumerisches-lcd-16x2-gr-252-n/gelb) and a [KY-040 rotary encoder](https://www.berrybase.de/en/components/passive-components/potentiometer/rotary-encoder/drehregler/rotary-encoder-mit-breakoutboard-ohne-gewinde-und-mutter)`
Update README.md [ci skip] 3 years ago
Add build instructions [ci skip] 3 years ago			`## Usage`

Update the firmware and bootloader [ci skip] 3 years ago			`* In the case of Raspberry Pi 4, Update the firmware and bootloader to the latest version (not doing this may cause USB reliability issues)`
Add build instructions [ci skip] 3 years ago			`* Download from [GitHub Releases](../../releases)`
			`* Unzip`
Add details to Usage section [ci skip] 3 years ago			`* Put the files into the root directory of a FAT32 formatted partition on SD/microSD card`
System Requirements 3 years ago			`* Put SD/microSD card into Raspberry Pi 1, 2, 3 or 4, or 400 (Zero and Zero 2 can be used but need HDMI or a supported i2c DAC for audio out)`
Update README.md [ci skip] 3 years ago			* Attach headphones to the headphone jack using `SoundDevice=pwm` in `minidexed.ini` (default) (poor audio quality)
			* Alternatively, attach a PCM5102A or PCM5122 based DAC and select i2c sound output using `SoundDevice=i2s` in `minidexed.ini` (best audio quality)
Restructure code and add new features (#37) * Make synth parameters configurable * Add class CConfig, which holds the configuration * Add template config file minidexed.ini * Register panic handler in CKernel to allow to display assertions * Fix: Performance timer did not show correct percent value with HDMI * Add class CDexedAdapter Some Dexed methods require to be guarded from being interrupted by other Dexed calls. This is done in the class CDexedAdapter. * Add class CUserInterface The user interface should be implemented here. As a start it supports showing the program number and name on the LCD display. The LCD output is buffered, so that LCD writes from an IRQ handler are possible. * Move MIDI handling from CMiniDexed to specific classes * CMIDIDevice is the generic MIDI handler * CMIDIKeyboard handles USB audio class MIDI devices * CSerialMIDIDevice handles the serial MIDI device * Now all MIDI inputs can work simultaneous * Program change and bank select work with serial MIDI * Add headers to all files * Include voices.c in sysexfileloader.cpp * Cleanup Makefile * Support headless operation on Raspberry Pi 4 Some code cleanup for src/kernel.* * Code cleanup for src/minidexed.* Move implementation of constructors to minidexed.cpp Reorder member variables * Support multiple USB MIDI inputs at once * Maximum 2 inputs on Raspberry Pi 1-3 * Maximum 4 inputs on Raspberry Pi 4 * Suppress frequent messages in MIDI dump * Use minidexed.txt * Document `SoundDevice` in `minidexed.ini` Co-authored-by: probonopd <probonopd@users.noreply.github.com> 3 years ago			* Alternatively, attach a HDMI display with sound and select HDMI sound output using `SoundDevice=hdmi` in `minidexed.ini` (this may introduce slight latency)
Add details to Usage section [ci skip] 3 years ago			`* Attach a MIDI keyboard via USB`
			`* Boot`
Document the menu [ci skip] 3 years ago			`* Start playing`
			`* See the Wiki for [Menu](https://github.com/probonopd/MiniDexed/wiki/Menu) operation`
Add build instructions [ci skip] 3 years ago
Add pinout Thanks @rsta2 https://github.com/probonopd/MiniDexed/issues/38#issue-1160260803 [ci skip] 3 years ago
			`## Pinout`

Spelling fix [ci skip] 3 years ago			`All devices on Raspberry Pi GPIOs are optional.`
Add pinout Thanks @rsta2 https://github.com/probonopd/MiniDexed/issues/38#issue-1160260803 [ci skip] 3 years ago
			`__CAUTION:__ All GPIO numbers are [chip numbers](https://pinout.xyz/), not header positions.`

Spelling fix [ci skip] 3 years ago			`\|GPIO \| Device \| \| Function \| Direction \| Comment\|`
Add pinout Thanks @rsta2 https://github.com/probonopd/MiniDexed/issues/38#issue-1160260803 [ci skip] 3 years ago			`\|---\|---\|---\|---\|---\|---\|`
			`\|14 \| UART \| \| TXD \| \| OUT \| \| serial MIDI\|`
			`\|15 \| UART \| \| RXD \| \| IN \| \| serial MIDI\|`
			`\|18 \| DAC \| \| CLK \| \| OUT\|`
			`\|19 \| DAC \| \| FS \| \| OUT\|`
			`\|21 \| DAC \| \| DOUT \| \| OUT\|`
			`\|02 \| I2C \| \| SDA \| \| IN/OUT \| \| used by some DACs\|`
			`\|03 \| I2C \| \| SCL \| \| OUT \| \| used by some DACs\|`
			`\|17 \| LCD \| \| EN \| \| OUT \| \| default setting\|`
			`\|27 \| LCD \| \| RS \| \| OUT \| \| default setting\|`
			`\|16 \| LCD \| \| RW \| \| OUT \| \| default setting, optional\|`
			`\|22 \| LCD \| \| D4 \| \| OUT \| \| default setting\|`
			`\|23 \| LCD \| \| D5 \| \| OUT \| \| default setting\|`
			`\|24 \| LCD \| \| D6 \| \| OUT \| \| default setting\|`
			`\|25 \| LCD \| \| D7 \| \| OUT \| \| default setting\|`
			`\|05 \| ROTARY ENCODER \| CLK (ENC A) \| IN \| \| default setting\|`
			`\|06 \| ROTARY ENCODER \| DT (ENC B) \| IN \| \| default setting\|`
			`\|26 \| ROTARY ENCODER \| SW \| \| IN \| \| default setting\|`
			`\|12 \| PWM AUDIO \| PWM0 \| \| OUT \| \| on Raspberry Pi Zero\|`
			`\|13 \| PWM AUDIO \| PWM1 \| \| OUT \| \| on Raspberry Pi Zero\|`
			`\|07 \| SPI \| \| /CE1 \| \| OUT \| \| reserved\|`
			`\|08 \| SPI \| \| /CE0 \| \| OUT \| \| reserved\|`
			`\|09 \| SPI \| \| MISO \| \| IN \| \| reserved\|`
			`\|10 \| SPI \| \| MOSI \| \| OUT \| \| reserved\|`
			`\|11 \| SPI \| \| SCLK \| \| OUT \| \| reserved\|`
			`\|04 \| NONE \| \| \| \| \| \| can generate clock signal\|`
			`\|20 \| NONE \| \| \| \| \| \| may be used for DAC DIN\|`

System Requirements 3 years ago			`## Downloading`

			`Compiled versions are available on [GitHub Releases](../../releases). Just download and put on a FAT32 formatted SD card.`

Move "Building" to wiki [ci skip] 3 years ago			`# Building`

			`Please see the [wiki](https://github.com/probonopd/MiniDexed/wiki/Development#building-locally) on how to compile the code yourself.`
Add build instructions [ci skip] 3 years ago
Add video, discussions and Wiki [ci skip] 3 years ago			`## Discussions`

			`https://github.com/probonopd/MiniDexed/discussions`

Move "Building" to wiki [ci skip] 3 years ago			`## Documentation`
Add video, discussions and Wiki [ci skip] 3 years ago
			`https://github.com/probonopd/MiniDexed/wiki`

Update README.md [ci skip] 3 years ago			`## Acknowledgements`

Update README.md [ci skip] 3 years ago			`This project stands on the shoulders of giants. Special thanks to:`

Update README.md [ci skip] 3 years ago			`* [raphlinus](https://github.com/raphlinus) for the [MSFA](https://github.com/google/music-synthesizer-for-android) sound engine`
			`* [asb2m10](https://github.com/asb2m10/dexed) for the [Dexed](https://github.com/asb2m10/dexed) software`
Update README.md [ci skip] 3 years ago			`* [dcoredump](https://github.com/dcoredump) for https://codeberg.org/dcoredump/Synth_Dexed, a port of Dexed for embedded systems`
Update README.md [ci skip] 3 years ago			`* [rsta2](https://github.com/rsta2) for https://github.com/rsta2/circle, the library to run code on bare metal Raspberry Pi (without a Linux kernel or operating system) and for the bulk of the MiniDexed code`
Update README.md [ci skip] 3 years ago			`* [smuehlst](https://github.com/smuehlst) for https://github.com/smuehlst/circle-stdlib, a version with Standard C and C++ library support`