SidecarTridge Croissant Keyboard Emulator for Atari ST/STe

Internal IKBD keyboard emulator for Atari ST and STE

The SidecarTridge Croissant is an internal keyboard emulator that brings modern Bluetooth input to the Atari ST and STE without turning the machine into an external-box project. It plugs inline on the 7-pin internal keyboard header and behaves like the IKBD the operating system expects. The original keyboard path stays available as a pass-through whenever you want stock behaviour.

Ships from Spain. For the Atari ST and STE with the 7-pin internal keyboard connector.

Key features

• Internal inline install: plugs into the 7-pin internal keyboard header inside the Atari case. No external dongle, no ribbon hanging off the side, no permanent motherboard modification on supported machines.
• Modern Bluetooth input: pair a Bluetooth keyboard plus the matching mouse or supported gamepad and use it on the Atari while keeping the machine behaviourally honest. Built around the IKBD model the operating system expects, not a simplistic key-translation layer.
• Original keyboard pass-through: pass-through mode keeps the original Atari input path active. Boot stock when you want stock behaviour, switch to Bluetooth when you want a modern setup.
• Boot-time mode selection: pick Bluetooth or pass-through at boot and Croissant keeps that mode on future power-ons until you change it. No jumpers, no rework.
• Wi-Fi web configuration: set pairing and the default startup mode from any modern browser. Croissant exposes its own Wi-Fi access point on first setup and joins your network afterwards.
• Field-updatable firmware: firmware updates land through the on-board micro-USB connector. No JTAG, no programmer, no Atari-side rituals.

Bluetooth and pass-through, not USB

Croissant is a Bluetooth and pass-through product. It does not take USB input devices. If you want to plug in USB keyboards, mice or gamepads, or you have an Atari Mega ST or Mega STE, the right product is the external Souffle dongle instead.

How it works

Croissant plugs into the Atari motherboard's internal keyboard header, and the original keyboard ribbon cable reconnects to the Croissant board. It can start in Bluetooth mode, providing modern wireless input while behaving like the Atari expects, or in pass-through mode, where the original keyboard path stays active. The default startup mode is set through the built-in web interface over Wi-Fi. For day-to-day use the device runs inside the computer with no external enclosure or dongle. The micro-USB connector is mainly for first-time setup and firmware updates.

Installation requires opening the computer and removing the internal metal shield. The shield acts as a Faraday cage and blocks the 2.4 GHz Bluetooth and Wi-Fi signals Croissant needs, so it stays out for good.

Installation overview

1. Open the Atari and remove the internal metal shield. It stays out; the shield blocks the 2.4 GHz radio Croissant needs.
2. Locate the 7-pin internal keyboard connector on the motherboard and disconnect the original keyboard ribbon cable.
3. Fit the Croissant board on the motherboard header, making sure the connector orientation is correct.
4. Reconnect the keyboard ribbon cable to the Croissant board so the pass-through path is wired up.
5. Power on the Atari and follow the Wi-Fi setup flow from any modern browser to pick the default startup mode.

Full step-by-step in the Croissant quickstart and the hardware installation guide.

Compatibility

Compatibility ultimately depends on the connector on your motherboard, not the model badge. Open the case before you order if you are not sure which connector your machine uses. See the compatibility guide for the full breakdown.

What you get

• Croissant board fully assembled and tested, latest stable firmware preloaded.
• Internal 7-pin keyboard header connector ready to mate with the Atari motherboard.
• Pass-through path for the original keyboard ribbon cable.
• On-board micro-USB connector for firmware updates.

You provide a Bluetooth input device of your choice plus a micro-USB cable for firmware updates. A modern phone or laptop is enough to run the web configuration interface.

Specs

• Connector to Atari: internal 7-pin keyboard header, IKBD-compatible signalling.
• Wireless: Bluetooth and Wi-Fi (2.4 GHz).
• Input support: Bluetooth keyboards plus supported mice and gamepads.
• Original input path: pass-through for the stock Atari keyboard and joystick wiring.
• Configuration: browser-based, served over Wi-Fi (access point and station modes).
• Firmware update: on-board micro-USB.
• Board revision: CROISSANT-IKBD REV1.1.0.

Good to know

• The internal metal shield must come out and stay out. It is a Faraday cage and blocks the 2.4 GHz signals Croissant needs.
• This is a homebrew product for hobbyists who enjoy running real Atari hardware and are comfortable opening the case. It is not a sealed appliance with a single-vendor warranty stack.
• Firmware downloads live on the Croissant firmware page.

New to the device? Follow the quickstart guide.