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/).
- [x] Runs on all Raspberry Pi models (except Pico); see below for details
- [x] Produces sound on the headphone jack, HDMI display or [audio extractor](https://github.com/probonopd/MiniDexed/wiki/Hardware#hdmi-to-audio) (better), or a [dedicated DAC](https://github.com/probonopd/MiniDexed/wiki/Hardware#i2c-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
* 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](https://github.com/probonopd/MiniDexed/wiki/Hardware#i2c-dac), HDMI display or [audio extractor](https://github.com/probonopd/MiniDexed/wiki/Hardware#hdmi-to-audio) 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 [LCDC1602 Display](https://www.berrybase.de/en/sensors-modules/displays/alphanumeric-displays/alphanumerisches-lcd-16x2-gr-252-n/gelb) (not i2c) 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)
* Put the files into the root directory of a FAT32 formatted partition on SD/microSD card (Note for small SD cards which are no longer sold: If less than 65525 clusters, you may need to format as FAT16.)
* 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 (alternatively you can build a circuit that allows you to attach a "traditional" MIDI keyboard using a DIN connector, or use a DIN-MIDI-to-USB adapter)
* If the system seems to become unresponsive after a few seconds, remove `usbspeed=full` from `cmdline.txt` and repeat ([details](https://github.com/probonopd/MiniDexed/issues/39))
* [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
