Denise ITX Amiga 500 Plus ITX Motherboard

Description

The Denise ITX A500 Plus clone is an Amiga A500 Plus motherboard reimagined using the ITX form factor or is also known as Mini-ITX. This form factor is direct from the PC world which means there are many case options available.

Below are the highlights of the Denise:

• Support for full ECS chipset and 2Mb chip memory on a standard 72-pin 2Mb Simm (A4000 style).
• Bigrom support to run AROS kickstart or ROM bank switch (27C800).Bank switching is controlled by scroll-lock & remembers its state.
• Internal RGB-Video header with important signals for rtg cards, scandoubler etc. No more ugly external video cables on the back to get monitor switching with graphic cards.
• An IO output from the microcontroller allows on/off control on some expansion boards with NUM-lock. Great for turning off hard drive controllers and fast-ram cards when you want to run floppy-based demos.
• A pinball game mode for the PC-keyboard can be activated. This disables reset with the WIN/APPS keys. But you can still use them as Left A and Right A. F11 and F12 still work as AA and the reset is done with CTRL, F11,F12
• Realtime Clock backed up by ATX-standby power-rail and supercap.
• ESD protection on all IO-ports like Joy/Mouse port, Parallel port etc. Protects them rare precious custom Amiga chips.
• The entire audio-signal chain from Paula is built with high quality film capacitors and audio grade electrolytic capacitors. The filter has the same characteristics as an A500 Rev8. But less distortion.
• Manually routed multi-layer PCB ensures good signal integrity and makes it less susceptible to electromagnetic interference. Sturdy power-rails with plenty bulk-capacitance on CPU-socket to support power demanding accelerator cards such as 060-cards.
• All ICs is through-hole mounted or sits in through-hole mounted sockets. Most surface mount components are on the back and the smallest are of the rather large 0805 size.

The Denise ITX motherboard provides direct access to the same ports available on the Amiga A500/A500 Plus on the back of the board but also includes a DIN Keyboard and DIN Mouse ports: Below is a list of ports available on the Alicia 1200.

External Ports:

• 1 x PS/2 connection for PC-keyboard or A4000 keyboard. Autosense, no jumpers needed.
• 1 x PS/2 Connection for PC-Mouse with auto switch between mouse and joystick. Multi-button and scroll wheel support.
• 2 x Joystick connectors.
• 1 x Serial port (DB25)
• 1 x Parallel port (DB25)
• 1 x Standard Video port (DB23) (Only high quality RGB video)

Internal Ports:

• 1 x Internal connector for Floppy disk drive with some extra features. With an expansion circuit board you get both an internal & external floppy connector. You can switch if DF0: should be internal or external. Autosense if drive is not connected to save boot time.
• 1 x 3-pin header for internal audio connection.
• 1 x 3.5mm jack for external audio.
• 2 x 100-pos Female Card Edge Connectors (Zorro II compatible)
• Pin header for connection of power button, reset button and power LED
• 24-pin standard ATX power supply connector

Combine this with an ITX case and PSU, you will have an expandable Amiga A1200 within an ITX form factor.

Build Service:

Like our Alicia 1200 build service, we will be offering fully built Denise 500 motherboards where we provide all the custom chips or a donor board is supplied and we strip and recycle and install them on the Denise. More details coming soon!

This project was made possible by: Enterlogic 

Manual here

*The A500 Plus donor board does not need to be fully working, if there are video, sound issues these are not an issue. The board does however need to be able to boot up and boot from a floppy/gotek. Chips are tested before installing.