The Yamaha YM2149F is a 3 voice software-controlled sound generator chip that was used in classic computers from the 1980s such as the Atari ST series. Also known as the AY-3-8910 before Yamaha gained licensed use of the chip with some minor modifications, most notably a higher rate & resolution volume envelope table. You can read more on the Wikipedia page.
This project's aim is to create a full fledged self contained multi-timbral MIDI synthesizer (via USB and hardware MIDI) utilizing several Demoscene & chip music tricks to enable a broader sound pallet other than basic square waves by use of software control via Teensy 3.2
Currently most of the information including source & schematic is located on the Github page in the link section. :)
YM2149F chip. Obtained from EBay or China outlet.
Code is completed and working well except for SYSEX patch editor and doc blocks (code comments). Currently working on getting non-bodged board design into KiCad. Next step will be adding MIDI out and thru, as well as a button encoder & LCD for patch editing.