The ACSI2STM is an open source hard drive emulator designed for Atari ST computers, enabling the use of SD cards as storage devices. Powered by an STM32 microcontroller, it bridges the Atari’s ACSI port with modern SD cards, providing a cost-effective, reliable, and versatile solution for expanding storage on vintage Atari systems.

Key Features:

• Broad Compatibility: Supports Atari models such as 520 STF, 1040 STE, Mega ST, and Mega STE.

• GemDrive Mode: Offers seamless access to SD cards formatted with FAT16, FAT32, or ExFAT. This mode eliminates the need for additional drivers, making it easy to transfer files between your Atari and modern PCs.

• ACSI Mode: Emulates traditional ACSI hard drives and supports multiple partitions. This mode requires Atari-compatible hard disk drivers, offering enhanced compatibility with legacy software.

• Real-Time Clock (RTC): Includes UltraSatan-compatible RTC functionality, enabling accurate timekeeping on the Atari. A 3V lithium battery (CR2032 not included) is required for this feature.

• Firmware Upgradeable: The ACSI2STM firmware can be updated directly from the Atari, ensuring compatibility with future enhancements and bug fixes.

Kit Contents

When purchasing the ACSI2STM kit, you’ll receive:

1. A PCB with all components soldered and tested, including the DB-19 connector for the Atari ACSI port.
2. A DB-20 connector to expand the ACSI port to Satan Disk and other devices. Not soldered.
3. Pre-installed latest stable firmware.

The user will have to provide:

• A USB-C cable to power the ACSI2STM.
• A SD, SDHC, or SDXC card to store files. They must be formatted in FAT16, FAT32, or ExFAT for GemDrive mode or with Atari-compatible hard disk drivers for ACSI mode as described in the documentation.
• A functional Atari ST/MegaST/STE/MegaSTE/TT computer with an ACSI port.

Installation

The ACSI2STM is already pre-assembled and embeds the latest firmware, making it ready for use out of the box. The only steps required are to prepare an SD card and connect to your Atari system:

3. SD Card Preparation

• For GemDrive Mode: Format the SD card with FAT16, FAT32, or ExFAT to allow the Atari to access files directly without additional drivers.
• For ACSI Mode: Create disk images or partitions compatible with Atari’s hard disk drivers for legacy software.

4. Operation

• Insert the prepared SD cards into the slots.
• Connect the ACSI2STM to the Atari’s ACSI port.
• Power the ACSI2STM using a USB-C cable (not included).
• Power on the system. The Atari should detect the SD card as a hard drive, ready for file storage and retrieval.

This product is intended for users familiar with basic embedded systems and vintage computer hardware. While we offer support for hardware setup and firmware installation, the firmware is provided as-is. It is actively and continuously developed, and we encourage users to contribute by reporting bugs and suggesting features on the GitHub repository.