PCB board emulator for Atari XL/XE SIO2SD

This is a popular open-source PCB project emulating a disk drive for 8-bit computers Atari XL/XE (e.g., 65XE, 130XE, 800XL). The device, called SIO2SD, connects directly to the SIO (Serial I/O) port, allowing you to load games, programs, and disk images from an SD/MMC card – no need for a real disk drive.

Main features and capabilities:

• Emulates up to 15 virtual disk drives (D1–D15) + additional virtual modes.
• Supports disk image files: ATR (read/write), XFD (read-only), COM/XEX (read-only).
• Navigation through SD card directories using a 16x2 LCD display (HD44780) and buttons (5 microswitches: S1–S5, e.g., K1–K4 + Shift).
• Turbo SIO mode (high-speed): adjustable speed (index 1–16, default 6 ≈ 69 kb/s), up to 127 kb/s with hardware modifications and Atari software.
• Supports SD/MMC/SDHC/SDXC cards in FAT12/16/32 file systems (with MBR/GPT partitions).
• Device configuration directly from Atari (configuration tool loaded from MCU flash or SD card).
• Additional functions: creating empty ATRs, write protection, quick disk mapping, simple turbo loader.

Compatibility:

• All 8-bit Atari with SIO port (XL/XE series).

Project:
https://www.pcbway.com/project/shareproject/ATARI_XL_XE_SIO2SD_Interface_PCB_AVR_software_v_3_X.html