The many octagons

There are several computer related octagons

Bell Labs tried to call the “#” the octothorpe. It's now a band
The Kalok Octagon hard drive had an 8 sided top:
Kalok was founded by a former Seagate engineer, the same man who had been largely responsible for the pioneering ST-225.
Kalok seemed to live on the edge of bankruptcy most of the time, and later morphed into JTS.
[ JTS also made unreliable hard drives and went bankrupt ]
A huge heavy 8 sided connector designed by Dimitry Grabbe for AMP, to connect 8 CPUs to a common core memory,
currently in the hotel basement.
A maker of embedded systems

It's the Octagon embedded systems that's of interest to IXR.

Professor Richard Gray Costello was my advisor and mentor when I was an undergrad at The Cooper Union school of Engineering.
I salvaged some of his embedded processor lab when the engineering labs were moved to the new "academic building".

Octagon systems embedded systems catalogue

I donated the embedded lab to IXR.
It contains one Micro-PC card-cage containing a complete
8-bit ISA bus system running DOS, with plenty of interface cards, software and manuals.

Even if you don't use the processor,
the I/O cards have extremely useful Interface Modules
for interfacing things with space for breadboarding your own circuit!

Interface Modules
	A small protoboard with connectors for a 20 pin ribbon cable to 1: 4 position and 1: 16 position screw terminal block.
	The STB-26 converts a 26 conductor ribbon cable to a screw terminal block. Really handy for connecting individual wires to a breadboard or circuit without cluttering it up with the individual wires.
	The TBD-100 Terminal Block Interface Module breaks out a 26 conductor ribbon cable to 24 parallel bits, each output to a screw terminal block and a buffered LED via 3: 2804 octal darlington transistor arrays
	The TBD-100 Terminal Block Interface Module tech specs and schematic

Not pictured: ribbon cable to sockets for solid state relays and industrial control modules.
The Crydom modules do NOT fit :-(

5970 prototyping card

with ISA bus buffering & decoding

and schematic!

Octagon embedded systems manuals

Manuals for many parts are still online here.
I downloaded these manuals (we might not have all these modules)

5664_manual.pdf for the SNAP I/O card
The 5664 card interfaces directly to Opto 22 SNAP-B series racks, which utilize the many SNAP I/O analog and digital modules available. The 5664 connects up to two, 16 position racks, for a total of 64 analog or 64 digital I/O points. Both analog and digital modules can be combined on the same rack. Up to two 5664 cards can be installed in an Octagon system.
5970_manual.pdf for the Prototyping Card
5974_manual.pdf for the PC-104 Card
PC-425_CPU_manual.pdf
PC-450_CPU_manual.pdf
PC-485_manual.pdf
The PC-485 is a serial adapter card that converts the serial port on an IBM PC from RS-232 to RS-485.
SBS_2400H_manual.pdf
The SBS-2400 Microcontroller is a 4.5" x 8" computer board that contains all the hardware and software necessary to create a control system. It uses a 64180 (Z80-like) CPU and can be operated in a stand-alone mode or in conjunction with other peripheral boards.
instruction_sheet_dev_system.pdf are the quick start instructions
ULN2804A.pdf
uln_280x.pdf
Spec sheet for ULN280x family of Octal High Voltage, High Current Darlington Transistor Arrays
The ULN2803 is designed to be compatible with standard TTL families
while the ULN2804 is optimized for 6 to 15 volt high level CMOS or PMOS
3: 2804s are used in the TBD-100 Terminal Block Interface Module to buffer the LEDs.

Spec sheet for 8-lead Slo-Syn stepping motors

ISA bus references

8 bit PC-XT bus pinout
16 bit PC-AT bus pinout

And from the Midatlanticretro mailing list:

designing for the ISA bus

On Tue, 26 May 2009, David Comley wrote:
A good place to start is the Art of Electronics which has a chapter on several long in the tooth buses, including the ISA bus (which lives on, incidentally, in PC/104 modules).
I believe it discusses the physical aspects of ISA bus adapter design. It covers I/O and memory port address decoding, interrupts and the handshaking of all the ISA bus signals.
I also found this site http://www.cryogenius.com/hardware/isacard/ to be very useful as a reference and there are schematics for port address decoding right there on the page.
I've recently done quite a bit of work on ISA bus timing for a legacy project for my business. Everything seems straightforward enough if you're only dealing with 8 bit data. 16 bit transfers are a little more complex and probably best avoided for a first time project.

updated 19-April-2012