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The FDX68 is an add-on device to the Raspberry Pi 3B / 3B+ (and potentially newer revisions) that enables one to emulate an X68000 floppy drive on a real X68000. This wiki page was created to mirror information found on the original creator's web site. Please reference the original web site first for the most up-to-date information.
Original web site: (http://www.geocities.jp/kugimoto0715/fdx68/index.html)
Background Information:
The X68000, like many other devices made in the 1990's and earlier, uses ICs that communicate on 5V rails (0V = binary 0, 5V = binary 1). Modern electronics, use 3V rails (or even less). Hence, one can't connect a micro computer like a Raspberry Pi to an X68000, as the data bus voltages are not compatible.
The FDX68 is a device that plugs into the Raspberry Pi, and voltage converts between a Pi and X68000 floppy drive port (both internal and/or external). The actual emulation of the floppy drive happens in software; a very clever Linux application that runs on the Raspberry Pi. The FDX68 emulates 2 FD at the same time; external jumpers set which drives to emulate (0/1 internal, or 2/3 external). Lastly, LEDs are included on the device to show you drive activity.
PreReq:
- Raspberry Pi 3B or 3B+
- Latest version of RASPBIAN OS for Raspberry Pi (Raspbian Stretch was used here)
- FDX68 device (purchase from original maker from above link)
- FDX68 interface cable (depending on X68000 unit you have, connector will differ)
- Knowledge of Linux (SSH into Pi, start service, run command line utilities to load disk images)
- Disk images of OS / Games you want to run
Setup and Usage:
The original author has great instructions found here: http://www.geocities.jp/kugimoto0715/fdx68/index.html Use google translate to get the details. The rest of this page was a result of edited google translate of original page (pulled 11/26/2018)
The following examples will not cover all possible combinations, but one should find the closest system and adjust accordingly based on connector and how they want to use the device. It is easiest to connect the FDX68 externally, but it can also be used internally (adjust drive assignment accordingly). Here are some important things to keep in mind:
- Newer systems have an external switch to select internal floppy drive assignment
- Older systems always assign internal FD 0/1 and you must set FDX68 to 2/3
- HumanOS can boot from any FD (0/1/2/3) So you can boot from external FD to do things like change SRAM settings or install SASI boot loader
- Single disk games can boot from FD 2/3
- Multi disk games will look for disk 2+ only on FD 0/1. This might be an issue with older systems that don't allow you to set internal FD assignment
- System will not boot a hard drive if FD0/1 are not present. So you must always have FDX68 running as drive 0/1 or you must have internal drives connected as 0/1 if booting SCSI devices.
X68000 XVI Compact:
Connection Method:
The external FDD connecter is labelled “EXTERNAL FDD” on the back of the X68000. This is a very unusual port known as the “miniature delta ribbon (MDR) 40 position female connector”. In order to connect an external device to this port an MDR 40 position male connector is necessary. The FDX68 author made a cable for converting this port to a standard 34-pin ribbon cable connector. One should be able to purchase the MDR 40 position male connector at many online retail stores. You will also need to purchase matching enclosure shell for the connector.
When making your own cable to convert from MDR 40 to the 34-pin connector found on the FDX68, the following conversion table should be referenced. The pin assignment for creating the conversion cable is as follows. After soldering the pins, one should confirm they cable is soldered correctly using a voltmeter.
Here's how one connects the FDX68 externally to the X68000 using this custom cable
