SOLD OUT! I will order a new updated run of boards when I get enough wait-list orders.

Introducing: The Multi-Plane for EXORbus!

The Multi-Plane for EXORbus is a backplane for Motorola EXORbus compatible computer modules, but that's not all! It also includes a fused ATX power connector with switch, can be used as a card extender, and has a small prototyping area (great for developing a small /Page Enable circuit for the Dynamic System Bus of multiple Dynamic RAM Modules).

Motorola's EXORbus is an old bus standard, pre-dating VMEbus and common ATX power supplies. It was used on the Motorola EXORciser, EXORset, a variety of "MEX" and MicroModule series boards, and "MEK" series trainers. There are also a lot of interesting third-party MC6800 and MC6809 based single-board-computers that use this form factor, which are finally affordable due to obsolescence as PLCs. However, accessories such as backplanes and power supplies are hard to find and still quite expensive. The Multi-Plane allows you to finally test and use these boards in a compact form factor matching the size of an EXORbus card.

What You Get:

• EXORbus passive backplane/extender PCB expandable to 9 card slots (8 vertical + 1 horizontal extension connector)
• Two 86 pin card edge connectors (additional connectors available as option)
• Fused ATX power connections (+5V, +12V, -12V only, no -5V) + 5 additional fuses
• Power switch (multiple options)
• LED power indicator (multiple color options)
• Two card edge protectors to prevent spurious signals (multiple color options)
• EXORbus card form factor
• Assembly is optional and extra
• Note that some of the above photos include optional accessories, or additional boards or power supplies which are not included for purchase.

What You Need to Add (Not Included):

• EXORbus compatible CPU or expansion cards
• ATX Power Supply (check Amazon)
• Your time and solder.

Prototype Board Details:

You are purchasing one board from my first run, at my cost, for the PCB and basic parts. Note the low price of the large edge connectors. However, there are some minor issues with the board that I may be fixing in the next revision:

• Some of the expected silk screen is missing (part names and values, pin letters).
• The large paddle power switch goes left for on and right for off. This is the opposite of the label on the switch, but I will add a sticker over the top to make it clear.
• There is no connection for -5V for old (unusual) Dynamic RAM modules. This signal was never standardized. You can easily add a jumper wire to the ATX power socket pin though.
• Pins /C and /D and 18 and 19 are connected as normal bus signals and are NOT set as a daisy-chained RAM refresh signals as required for some (unusual) Dynamic RAM module configurations.
• The top edge card extension connector is not engineered as well as I would like. With the PCB mount edge connectors that I have, it may be unstable for repeated insertion and removal of cards. I can cut a slot in one of the connectors that may improve stability for you, at your request. The extension was designed for solder eyelet-type card edge connectors which I cannot obtain at a reasonable price. You may have a stronger connection if you install your own solder eyelet-type edge connector or right-angle edge connector.
• The 12V GND at pin /B is not connected. This is very rarely used by modules. You can easily add a jumper wire to GND if needed.
• I may flip the backplane around so the switch is in the front for future revisions. Let me know your input.