Click on the my projects folder in the menu at the left side to see the following subfolders :
- Homebrew 'PDP-11'
With this project, all the fun started ...
Running a PDP-11 simulation with SIMH (on a PC, but it can be any other computer for which you can compile the C source code)
is just half the fun, because you do not get the blinkenlight console. As the source code is available, you can make changes.
I built a scaled replica of the PDP-11/35 console with all the switches and lights and designed an I/O Board plus Core
Board to control the "blinkenlight console". The Core Board has a 6809 processor and it can communicate over a serial link.
The SIMH source code is changed (a very little), so that SIMH sends information over the serial link to the Core Board to
activate the appropriate LEDs, and SIMH can receive information from the Core Board about the status of the switches.
Et voilÓ, there you have your PDP-11/35 with a real console, running on a PC. Project status:
- Homebrew 'PDP-8'
While searching for some information about the 6809 processor, I stumbled upon a .zip file that contained a simulator for
the instruction set of the pdp8, written in 6809 assembler. I thought "that would be a fun project: a pdp8 running on
the Core and I/O Board".
Of course with a console with all the switches and LEDs. The 6809 assembler code
turned out to be working, but there were a few bugs to be solved ... I built a scaled replica of the pdp8/e console, and
added a hard disk drive interface over the I/O Board to simulate an RF08 disk. Read all about this project!
Latest update: I wrote the 6809 simulation software to add a floppy disk (see project description
below) to the pdp8/e simulator as an RX01 device. It is not yet tested ...
- Homebrew 'full-size PDP-8'
On UseNet, I was able to buy the almost complete panel with switches of a PDP-15. Pity that the front was not complete,
I would have build a PDP-15 simulation with SIMH behind it. The switches have been without use for 2 years, until I
contacted John Kent. He developed a 6809 in an FPGA, and this "core" runs at 12.5 MHz comparable clock with the real
6809. It would be perfect to "upgrade" the pdp8/e simulation to make it perform better.
But then, why not put a "pdp8 core" in the FPGA? Hans Pufal already developed a pdp8 core. John, Hans, Vince and I
bought an FPGA development board from XESS. Vince already started drawing boards in Eagle as replacement boards for
in a real pdp8/i. So, besides the board for the switches and the lights, an additional board set was developed to
serialize the data from the switches and deserialize the data for the lights and connect each lamp to an output of
the shift registers. This approach save a lot of I/O lines from the FPGA freeing them for other uses like connecting
an IDE hard disk, a SD card, and (future option) implement an OMNIBUS to connect real pdp8 peripherals!
- SpareTimeGizmo's SBC6120
This is a project offered by SpareTimeGizmo. The availability of this Build-It-Yourself kit depends on the availability
of some crucial parts, especially the 6120 processor which is a Harris implementation of the pdp8 processor on a single
chip! But the great development from Bob is the FP6120, which add a nice front panel to the SBC6120. This is a separate
project, and again, the availability depends on special parts, in this case the front panel (made in small quantities
when complete SBC6120 kits are available) and the switches which are special-order (thus you need a minimum quantity).
Note that these kits are not cheap. The front panel is some $75, the printed circuit board is big, and the switches are
some $6 each, which adds up! Count the number of switches ...
It may not be cheap, but you can be the proud owner of a self-built "pdp8/e" which can can all pdp8 software, even OS/8.
- Floppy disk
The transfer of data to the pdp8/e simulation is not "smooth". It is fairly easy (from a hardware point of view) to add
a floppy disk interface. When the software is written (that is more work...), the floppy disk is a simple option to
exchange pdp8 or 6809 software. The slow initial software loading remains though ... Project
status: the hardware is built and tested and a (working) native Disk Operating System for the 6809 is written with a (text-based)
command-line interface. Common commands are implemented, like format, save, get, protect, delete, rename, squeeze, and dir,
of course. I would like to add a possibility to *read* a simple FAT-formatted disk (without directories).
- FlipChip Tester
The older PDP's (like the pdp8) use a lot of small modules, called FlipChip, to construct a logic device. These small
modules often only contain a few ICs that are basic building blocks like the M113, which is one module with ten 2-input
NAND gates functionality. The FlipChip Tester is based on the Blinkenlight boards. To build the Tester you need one
"extension" board that connects to the Blinkenboards and a board with a DEC backplane connector to put the FlipChip in
that you want to test. A PC program talks to the Core Board firmware and runs the test. ... Project
status: the hardware is built and tested. The firmware for the Core Board is written and tested, and a DOS-/CMD-based program is
written and tested (no GUI yet). An *automatically generated* testvector data file (from a script) tested an M113 FlipChip module
- PDP-11/70 console
Again, a project based on the Blinkenlight boards, and just that! You need the Core and I/O Board, a small PC board
and a real (PDP-11/70) console. The latter two can occasionally be bought on eBay. It is a lot of mechanical work,
and the wiring is also some work, but imagine a "real" blinkenlight PDP-11 on your desk! (See also the "Homebrew 'PDP-11' project).
It has the same handling and response of the LEDs and the switches/toggles as a real PDP-11, so if you do not want to be lazy, or
just like to toggle in a bootstrap program for RK05 (that's a short one), or RX02 or RL02, go ahead!
Project status: the Blinkenlight Board set is connected to the real 11/70 console, and a mini-PC is
incorporated. The mini-PC has a 800 MHz Pentium III CPU, and its performance is adequate to produce a smooth "blinkenlight"
effect. Thanks to some software additions from John Dundas most of the lights on the 11/70 console are functional! A 7 MB movie
clip of the SIMH with this PDP-11/70 front panel booting RT11 from an "RL02" can be made available on request.
- HP 1000E console
I won on eBay two HP 1000 front panels, one E-series, and one F-series front panel. I had bid on them because I wanted
to use the Blinkenlight Boards to bring these panels also to "life", just to prove that the Blinkenlights Boards can be
used for something else than PDP-11 front panels. Actually, you can use the Blinkenlights Boards for just about anything
you want to control from a PC, it is simply a matter of modifying (a part of) the firmware. OK, you need to understand
6809 assembler, but may that is part of the fun? While you go you can actually learn new things! You don't need to burn
an EPROM to test yoyr assembler code, because you can use he monitor to download your code and give it a try. Set a
breakpoint, check the CPU registers ... and before you know it you are debugging in the old-fashioned way like many
dd before you in the seventies!
Project status (april 2010): the Blinkenlight Board set is mounted on the rear side of the HP 1000E
front panel and the 6809 firmware is written. The SIMH file scp.c is modified and the first "blinkenlight show" is a fact!
- RTTY with a PDP-11
One of my other hobbies is HAM radio. My callsign is ... PA8PDP.
A new fun project is more on the software side on a PDP-11, the decoding of RTTY signals. These signals from radio
amateurs all over the world, are some of the "strange" beeps you can hear on a shortwave receiver. But there are a lot
more of those signals that are not RTTY (Radio TeleTYpe). You need a modem to convert the audio tones into a digital
signal, and feed that to a digital input of a PDP-11. As I will write the software in C, it will be easy to port it
to a (micro)VAX. I have a PDP-11/53 in a BA23 box, and a ÁVAX II in a BA123 box ... Project status:
very early stage!