A programmable TOS ROM emulator for the Atari ST, STE, and Mega series
Welcome to SidecarTridge TOS Emulator, a programmable TOS ROM emulator and TOS ROM replacement designed specifically for the Atari ST, STE, and Mega series. Elevate your Atari experience by effortlessly switching between multiple TOS versions and custom ROMs without the need for physical ROM swaps. The kit is based on the SidecarTridge ROM Emulator board.
Why Choose SidecarTridge TOS Emulator?
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Run Any TOS Version or Custom ROM: The device allows you to access any TOS version or custom ROM without physically swapping ROM chips. Experience the flexibility to switch between versions and try new firmware like EmuTOS with ease.
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Fits Inside Your Atari ST Case: The device integrates perfectly within the Atari ST case. It connects directly to the motherboard, ensuring your Atari ST operates as usual, with no need for modifications.
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Simple USB Connectivity: Connecting the device to your computer via USB allows for easy transfer of TOS image files. The device appears as a mass storage device, making the process straightforward across Windows, macOS, and Linux.
Key Features
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Bit-Banged Emulation: Leveraging the powerful Programmable Input Output (PIO) features of the Raspberry RP2040, it emulates the internal ROMs of the Atari ST series by replacing them. This method eliminates the need for custom firmware or complex hardware configurations, providing a seamless emulation experience.
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Multi-TOS Version Support: With 16MB of flash memory, you can store and access up to 64 different TOS versions. This vast storage capacity means you can easily switch between different TOS versions without physical ROM swaps.
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Experiment with Custom ROMs: The device supports any ROM image file, including custom ROMs and open-source TOS replacements like EmuTOS. This feature allows you to enhance the functionality of your Atari ST and explore new possibilities.
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Easy Software Management: The SWITCHER.TOS software provides an intuitive interface for selecting and managing TOS versions and custom ROMs directly from your Atari ST. This user-friendly approach simplifies the process of switching ROMs, making it accessible for all users.
How It Works
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Bit-Banged Emulation: Bit-banging involves manually driving the signals that would typically be handled by dedicated hardware. The device generates the necessary address and data signals to fully emulate the original ROM chips. Utilizing the PIO capabilities of the Raspberry RP2040, the emulator mimics the behavior of the original 27CXXXX integrated circuits used in Atari ST computers, even at high frequencies.
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Flash Memory Storage: The device uses 16MB of non-volatile flash memory to store TOS image files. Connect the emulator to your computer via USB to manage ROM files easily. The device appears as a FAT16 mass storage device, allowing for straightforward copying and management of TOS images and custom ROMs.
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Hot Swapping the ROMs: Upon powering on, the device is active and ready to provide the necessary ROM signals to the Atari ST. The computer boots as usual, with no need for hardware modifications or additional steps. The SWITCHER.TOS software lets users select and switch between different TOS versions effortlessly.
Perfect for a Range of Users
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For Atari ST Enthusiasts: Upgrade your Atari ST with modern capabilities and easily switch between various TOS versions and custom ROMs.
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For Developers: Developers can test applications across different TOS versions and custom firmware without relying on software emulators.
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For Retro Computing Hobbyists: Hobbyists dedicated to retro computing will appreciate the convenience and non-invasive way to run and experiment with different operating systems.
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For Retro Computing Repair Shops: Professionals providing support for vintage Atari ST computers can quickly and easily test different TOS versions, aiding in troubleshooting and repairs.
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Before Purchasing Find Your Right Kit for your Atari ST
The SidecarTridge TOS emulator is designed to work with specific Atari ST models and motherboards, with different versions available to accommodate various configurations. Before purchasing the emulator, follow these steps:
- First, check your Atari ST motherboard model by opening the case and locating the model number, typically found in the middle bottom of the motherboard. Refer to the Compatibility section for supported motherboards, and if your model is not listed, contact us for assistance.
- If your model is listed, proceed to determine the number of ROM chips on your motherboard. Currently, the emulator supports motherboards with two ROM chips; support for six ROMs will be available in a future version.
- Check whether the ROMs are plugged or soldered—if they are soldered, you will need to desolder and install sockets.
Once compatibility is confirmed, purchase the appropriate SidecarTridge TOS emulator kit based on your motherboard model and the number of ROMs.
| SidecarTridge TOS Emulator Kit | Supported Motherboards | Number of ROMs |
|---|---|---|
| STF and STFM Kit | 070789-001, C103175-001, C103414-001 | 2 |
| STF and STFM Kit | 070789-001, C103175-001, C103414-001 | 6 |
| STE Kit | CA4003290 | 2 |
| Mega ST Kit | C103544-001, C103277, C100167 | 2 |
| Mega STE Kit | CA400677 | 2 |
Frequently Asked Questions
What is the difference between the TOS emulator and the Multi-device?
They are different beasts. The TOS emulator replaces the internal ROM TOS with a custom board, making it as easy to change TOS versions as it is to change files in RAM. It’s a replacement for an existing computer part. The Multi-device connects to the expansion port and can emulate different devices like external ROM (but not the TOS ROM), floppy, RTC, hard disk, etc. It works as an expansion device, not a replacement for an existing computer part.
Is the SidecarTridge TOS for me?
SidecarTridge TOS is a homebrew product designed for hobbyists with a keen interest in experimenting with their computers. If you seek a seamless, Apple-like experience, it may not meet your expectations.
Can the device harm my computer?
SidecarTridge TOS has undergone extensive testing on various Atari ST, STE, MegaST, and MegaSTE computers. It is designed to be safe for your computer. However, as with any electronic device, especially vintage computers, there is always a risk of damage. We strongly recommend following the installation instructions carefully and ensuring that the device is correctly installed.
Is it difficult to install the SidecarTridge TOS?
If your computer has socketed ROMs, the installation process is straightforward and does not require any soldering or permanent modifications to your Atari ST. If your computer has soldered ROMs, you will need to desolder the existing ROMs and install sockets. This process requires soldering skills and experience with electronics.
Does it work with all Atari ST models?
At this time, SidecarTridge TOS is compatible with the Atari ST, STE, MegaST, and MegaSTE models with two and six socketed ROMs. The device is not yet compatible with models that have six ROMs. Please read the Before you buy section of the documentation for more information.
What is the maximum size of the ROM image that can be used?
The SidecarTridge TOS supports ROM images up to 256KB in size. Keep in mind that the Atari ST/MegaST series needs TOS of 192KB, and the STE and MegaSTE need TOS of 256KB.
How many ROM images can be stored on the SidecarTridge TOS?
The current version of the firmware supports up to 64 ROM images. The SidecarTridge TOS has 16MB of flash memory, which is more than enough to store all the TOS versions and custom ROMs you need. Future versions of the firmware may increase this limit.
Can I use the SidecarTridge TOS with EmuTOS?
Yes, the SidecarTridge TOS supports EmuTOS out of the box, as it is the TOS image that is loaded by default on the device.
Can I use the SidecarTridge TOS with other custom ROMs?
Yes, we have tested the SidecarTridge TOS with EmuTOS and other custom ROMs, and it works well. You can use any ROM image file that fits the size requirements.
Can I use the SidecarTridge TOS with any existing TOS version?
Yes, the SidecarTridge TOS supports any TOS version that fits the size requirements. You can use any TOS version from 1.0 to 2.06. As a reminder, TOS is copyrighted material, and you should own a legal copy of it before using it with the SidecarTridge TOS.
Does the SidecarTridge TOS support 16Mhz mode in the MegaSTE?
Yes, the SidecarTridge TOS supports the 16Mhz mode in the MegaSTE. The device is compatible with the MegaSTE and can be used in both 8Mhz and 16Mhz modes.
Does the SidecarTridge TOS support cache enabled in the MegaSTE?
Yes, the SidecarTridge TOS supports the cache enabled in the MegaSTE. The device is compatible with the MegaSTE and can be used with the cache enabled.
Can I upload and delete TOS ROM images from the Atari ST computer?
Yes, starting from version 2 of the firmware, you can upload and delete TOS ROM images from any Atari ST/MegaST/STE/MegaSTE computer. This feature is useful if you want to upload a new TOS ROM image without the need for a computer with a USB port and/or the need to open the Atari ST computer case. If your device has an older firmware version, you can update it to the latest version to access this feature.
Can I use the SidecarTridge TOS with modified computers with CPU accelerators?
At this moment, it has not been tested on any computer with a CPU accelerator. The device is designed to work with the original Atari ST, STE, MegaST, and MegaSTE computers. If you have a modified computer, you should test it first to ensure compatibility.
Why don’t you ship to some European countries?
I’ve made the difficult decision to discontinue shipping to Austria, Bulgaria, Cyprus, France, Greece, Latvia, Lithuania, Luxembourg, Portugal, Romania, Slovakia, Spain and Sweden. This decision was not made lightly and is primarily due to the specific and significant costs associated with recycling packaging and electronics in these countries. Unfortunately, these costs are disproportionately high relative to the demand I’ve experienced, making it unsustainable for me to offer the products in these markets while adhering strictly to the legal requirements.
However, you can still find this and other products in various marketplaces like eBay, Tindie and others with a simple search.
Links and Resources
Experience the ultimate in Atari ST flexibility and functionality with the SidecarTridge TOS Emulator. Whether you’re a developer, enthusiast, or repair professional, this powerful tool is your gateway to a modernized and versatile Atari ST experience.
