The PFDBK Disk Unit Emulator

Front This is an implementation of William R Cooke's floppy emulator for the Arduino line of microcontrollers. William created this in 2019, but only now I build my own version. For now it uses an Arduino Mega 2560 and some standard interface boards (proto-sheld, SD-card and RS-232c).
The code is functional identical to the original from William, but some extensions are planned like changing disk images via the debug/programming interface. This might take some time, so I made the page first.

Back The wiring of this connector requires a #725-F9 cable (the original #725 has a 25 pin conenctor).
The rubber bands are to keep the lid shut. The planned self clamping didn't work out as expected. The colour scheme is somewhat accidental, as the filament ran out twice during printing all the versions of the parts.

Inside The contents is an Arduino Mega 2560, an experiment shield and two breakout boards for the SD-card and serial port.

Front This is a cheaper implementation based on the Arduino Pro Micro.
The code is functional identical to the original from William, but some extensions are still planned. At least there are lights indication disk (SD-card) access and SERIAL port activity.

Back The back side contains the connections to PX-4/PX-8 and the optional host interface, doubling as power input. There is also a reset button. The host interface allows changing the configuration; which disk image is mounted on which drive and a disk-level write protect. These are the functionality to be controlled from the PX-4/PX-8, but that functionality still has to be build.

Inside Lots of space inside, but a smaller case, can become a problem with stiff cables.
The board is also prepared for a more discrete RS232C interface with separate MAX232, capacitors and sub DE-9 plug.

Changes to the PFBDK firmware

The Arduino sketch is modified to run on both the Arduino Pro Micro and Arduino Mega 2560. Some new commands were added to the EPSP functions to support some management of the images on the SD-card.

The files in the root directory of the SD-card can be listed, mounted on the drives, and set to write protected. New, empty images can be generated.

Some PX-4 specific programs are created to manipulate the SD-card:

pfdir4 [n] - lists the files in the root directory of the SD card. The output is eight file names per part, the ENTER or SPACE key can be used to fetch the next part. The optional part number specifies the start part.
pfmnt4 [d] [ffffffff.eee] - mounts file ffffffff.eee on drive d. No arguments show the current 'mount table'.
pfwp4 [d] [s] - sets drive [d] to write protect state [s]. s = 0 for off and 1 = on. No arguments show the current write protect state for all four drives.
pfnew4 ffffffff.eee - generates a new and empty image file in the root directory of the SD-card

More information on the Github page with my fork of the Arduino sketch

Local links:

Schema of the Mega 2560 experiment shield version
Schema of the Pro Micro PCB
Schema of the Pro Micro PCB, with RS-232-c port fix
The cereal PX8 and PXDock archives unpacked into 20 images
TF-20 page,
PX-4 page,
PX-8 page,
Epson Serial Protocol used between TF-20 and HX-20, PX-8, PX-4,
3D-printer files. Open SCAD & STL's.
KiCAD files for the Arduino Pro Micro board version 1.0. It works well, but no chaining / multi-device suppert.

External links:

Last update: 2023-12-20

fjkraan@electrickery.nl

Front		This is an implementation of William R Cooke's floppy emulator for the Arduino line of microcontrollers. William created this in 2019, but only now I build my own version. For now it uses an Arduino Mega 2560 and some standard interface boards (proto-sheld, SD-card and RS-232c). The code is functional identical to the original from William, but some extensions are planned like changing disk images via the debug/programming interface. This might take some time, so I made the page first.
Back		The wiring of this connector requires a #725-F9 cable (the original #725 has a 25 pin conenctor). The rubber bands are to keep the lid shut. The planned self clamping didn't work out as expected. The colour scheme is somewhat accidental, as the filament ran out twice during printing all the versions of the parts.
Inside		The contents is an Arduino Mega 2560, an experiment shield and two breakout boards for the SD-card and serial port.
Front		This is a cheaper implementation based on the Arduino Pro Micro. The code is functional identical to the original from William, but some extensions are still planned. At least there are lights indication disk (SD-card) access and SERIAL port activity.
Back		The back side contains the connections to PX-4/PX-8 and the optional host interface, doubling as power input. There is also a reset button. The host interface allows changing the configuration; which disk image is mounted on which drive and a disk-level write protect. These are the functionality to be controlled from the PX-4/PX-8, but that functionality still has to be build.
Inside		Lots of space inside, but a smaller case, can become a problem with stiff cables. The board is also prepared for a more discrete RS232C interface with separate MAX232, capacitors and sub DE-9 plug.