ESP32-S3 board with VGA and audio output during development. (Credit: Ivan Svarkovsky)
The ESP32-S3 is by many metrics quite the powerful little computer, which has led to it being used even for things like emulating retro consoles and similar. Here [Ivan Svarkovsky]’s S3-MSX-PC project pushes the envelope by taking the multi-system Retro-Go project’s MSX component and optimizing it for the ESP32-S3’s Xtensa Lx7 CPU cores.
The project involves an ESP32-S3 as the core, requiring at least 8 MB of PSRAM (N16R8 configuration) to match the tested configuration. Any software is loaded into PSRAM before it’s executed, with the MSX1, MSX2 and MSX2+ supported.
For audio you have to wire up your own PDM filters to connect to the two GPIO pins that are used for audio output, while VGA output is handled by a basic 2-bit R-2R RGB222 DAC. For input devices you can use any USB keyboard, while software is added via the web interface or directly onto an SD card.
The Technical Deep Dive section goes into more detail as to what exactly got changed – with the blessing of the fMSX author – in the original fMSX core, such as targeting the Lx7 core’s cache dimensions and optimizing hot paths to avoid bottlenecks. Memory accesses were aligned for Xtensa and moving certain data from Flash to RAM was another change, along with the prevention of pipeline flushing due to certain branching decisions.
Considering that MSX specifications are based on a Z80 core, it’s not so crazy that one of these ESP32-S3 MCUs can effectively emulate them. The Retro-Go project itself claims to cover a whole swath of Nintendo and Sega consoles, as well as others, making it almost too easy to do some retrogaming without even having to drag out a Raspberry Pi SBC or so.