NESEMU: emulates the NES game console on an ESP32 with a 320x240 ILI9341 TFT screen, audio output, various controller inputs and SD card
NESEMU uses the Arduino IDE framework to compile and flash/upload the binary to an ESP32 module (wemosmini).
---------
| 25 |--------> audio out
| | gnd <-> gnd
| |
| 5 |--------> LCD ILI9341 CS
| 0 |--------> LCD ILI9341 RESET
| 2 |--------> LCD ILI9341 DC
| 23 |--------> LCD ILI9341 MOSI
| 18 |--------> LCD ILI9341 SCLK
| 19 |--------> LCD ILI9341 MISO
| | 3v3 <-> LCD ILI9341 LED
| ESP32 | 3v3 <-> LCD ILI9341 VCC
| | gnd <-> LCD ILI9341 GND
| |
| 15 |--------> SD card CS
| 13 |--------> SD card MOSI
| 14 |--------> SD card SCLK
| 12 |--------> SD card MISO
| | 3v3 <-> SD card VCC
| | gnd <-> SD card GND
| |
| 4 |--------> PSX controller CMD
| 21 |--------> NES/SNES/PSX controller DATA/DAT
| 22 |--------> NES/SNES/PSX controller CLOCK
| 27 |--------> NES/SNES/PSX controller LATCH/ATT
| | 3v3 <-> NES/SNES/PSX controller VCC/3V3
| | gnd <-> NES/SNES/PSX controller GND
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NES ___
DATA |o o| NC
LATCH |o o| NC
CLOCK |o o/ 3V3
GND |o_/
SNES _
3V3 |o|
CLOCK |o|
LATCH |o|
DATA |o|
|-|
NC |o|
NC |o|
GND |o|
-
PSX ___________________
\o o o|o o o|o o o/
-----------------
1 2 3 4 5 6 7 8 9
1->DATA, 2->CMD, 4->GND, 5->3V3, 6->ATT, 7->CLOCK, 9->ACK
The emulator is based on the nofrendo emulator (by Matthew Conte) which was ported to the ESP32 esp-idf framework by SpriteTM. Later versions from different people added various extras to the build. This version uses the code from various sources originating amoung others from "MittisBootloop" version and the build was then transfered to the Arduino IDE framework as a friendlier development platform. Note that this is still work in progress and not all features has been fully tested. Lot of effort went into getting the emulator to shift data fast enought through the SPI interface to the LCD to make it run as fast as possible. Currently the CPU (in a separate task) is just as fast as transfering data with DMA. There is options to stretch the screen along the X-axis but it has two drawbacks, if the game is of scrolling type then the crude upsampling (only CPU mode with interlace supports bilinear upscaling) will make some pixel flickering. Due to the larger amount of data it will take longer to transfer to the LCD but for interlaced mode and SPI running at 80MHz it is still a viable option. Pressing select and left simultaneously will bring up the in game menu while pressing select and start will do a reset. To get back to the ROM menu you'll need hit the reset button on your ESP32 module or power cycle the ESP32.
The file config.h in the top directory contains a few options and settings as well as the ESP32 pin mapping. Note that the LCD needs to use the VSPI interface to work fast/properly, additionally there is an option to rotate the screen 180 deg. The screen is up scaled (256->320 pixels) with either crude nearest sample or bilinear (the x axis up scaling can be turned on and off in the in game menu select + left). Due to some coding tricks bilinaer is just as fast as the more crude nearest sample but bilinear looks much better. Y axis is not scale at all. The default way to update the screen is in interlaced mode (odd/even lines as opposed to progressive, full screen update) using the CPU/SPI buffer. This will allow the refreshrate to hit 60FPS even with the screen stretched along the x-axis. There are options to use DMA but in its current form there is no speed benefit over the CPU. ROMs can be put on the SD card (formatted as FAT) with 8.3 file names and then mapped to the file menu with the "roms.txt" file that also needs to be in the root dir of the SD card. Note that the selected ROM gets memory mapped in the internal EEPROM of the ESP32 which means some wearing on its finite amount of write cycles (100k writes?). If the same ROM is selected after reset or power on then only a verify (no write) will take place to make sure the data is intact. This will then avoid a rewrite of the ROM image to the EEPROM.
The code base supports different types of controllers but only one at the time. Supported ones are NES, SNES, PSX or raw GPIO buttons (last two are not tested by me). Select the one you want in the config.h file
Use the Arduino IDE framework to compile and upload to the ESP32 (tested with V1.8.13 with ESP lib V1.04)
Bit of a mixed bag here... Code in this repository is Copyright (C) 2016 Espressif Systems, licensed under the Apache License 2.0 as described in the file LICENSE and components of nofrendo is Copyright (c) 1998-2000 Matthew Conte (matt@conte.com) and licensed under the GPLv2. Any changes in this repository are otherwise presented to you copyright myself and lisensed under the same Apache 2.0 license as the Espressif Systems repository.
Enjoy, Corn