EDUC-8 Project

[teenix]

Hi all,

Not really calculator related but I've been sent away working remote again, so to fill in some free time, I created an emulator for the EDUC-8 microcomputer.

This was originally designed by Mike Rowe when working for the Electronics Australia magazine around the time of the HP65 (1974) and was almost the first home build computer project. It was pipped at the post by the Mark-8 computer based on the Intel 8008 processor. The EDUC-8 did not have a processor, just a lot of TTL chips, and 32 bytes of memory which was expanded to 256 by the time of publication due to falling prices. I still remember buying those magazines back then and reading about this project but at the time it seemed a bit complex project for a school lad and it a bit costly too, quoted at around $300. It was named a "micro" computer because of how "small" it was. Not really battery compatible, as it drew around 15 watts.

I have included a code compiler, memory viewer and interfaces for the OCTAL LED display, Keypad and Paper Tape Reader.

As far as calculators go, it would surely be a coding challenge to get this old girl working as one, but if I get time, I might try and interface it to the HP97S just for the exercise.

It is Windows based and available at

http://www.teenix.org/EDUC8.zip

cheers

Tony

[teenix]

Couldn't resist

I interfaced to EDUC-8 to the HP97S emulator.

The EDUC-8 sent some numbers (1, 5, 255 and 47) to the HP97S via its BCD interface.

On reception of the number, the HP97S then ran its simple program from LBL A.

f LBL B
0
STO 1 // initialise 1 = 0
f LBL C
h CF 3 // enable 97S interface
R/S // stop
f LBL A
PrintX // print received value from interface
STO + 1 // add and store
RCL 1 // get total
PrintX // print it
GTO C // wait for more

Somewhat useless of course, but who would have thought back in the day that these two would get together :-)

cheers

Tony

[Harald]

Never heard of the educ-8 before, but it looks like an interesting toy!

[mfleming]

Any chance the schematics or logic diagrams are available? Might be fun to implement this in an FPGA demo board.

~Mark

[Dave Frederickson]

(05-12-2018 01:42 PM)mfleming Wrote:  Any chance the schematics or logic diagrams are available? Might be fun to implement this in an FPGA demo board.

Everything you need to build your own EDUC-8, including schematics, can be found here,

http://www.sworld.com.au/steven/educ-8/index.html

[teenix]

(05-12-2018 01:42 PM)mfleming Wrote:  Any chance the schematics or logic diagrams are available? Might be fun to implement this in an FPGA demo board.

~Mark

I might build a USB powered PIC based one just for nostalgia. I wanted to as a young fella, so might be a chance now. A few dollars for parts and a some extra for switches and PCB.

cheers

Tony

[mfleming]

Thanks for the link Dave!

(05-12-2018 09:03 PM)teenix Wrote:  I might build a USB powered PIC based one just for nostalgia. I wanted to as a young fella, so might be a chance now. A few dollars for parts and a some extra for switches and PCB.

cheers

Tony

Ah, but what's the fun of reproducing an old classic if not at the gate level? Sub-$20 FPGA demo boards are available. I know when the PiDP-11 is finally available, mine will be a cycle-accurate implementation

[teenix]

(05-12-2018 09:03 PM)teenix Wrote:  I might build a USB powered PIC based one just for nostalgia. I wanted to as a young fella, so might be a chance now. A few dollars for parts and a some extra for switches and PCB.

Hi all,

I managed to get the old (new) EDUC-8 beast working.

I had a lot of help from a kind person who has a real working EDUC-8 who helped to make sure all the logic was correct.

Attached is a photo of my EDUC-8 board which is much more compact than the original. Both the Windows emulator and the board show the result of multiplying 11 by 11 and shown in the accumulator register (bottom left row of LEDs)

I still have to do code for the hardware input/output but I have to wait for a new PCB design coming which supports the 3 serial IO ports and the parallel input port. It also allows using sub miniature toggle switches as well as the cheaper but larger ones shown.

The Windows EDUC-8 emulator also supports connectable modules for all the peripherals that were described in the original articles. These include LED displays, Keypad, ASCII keyboard, Melody Player, Paper Tape Punch/Reader, Magnetic Tape Storage, and a Mosaic Printer

I could not recreate the old Burroughs self scan display module as I cannot find information on it.

If anyone wants to play with the emulator, it is available at

http://www.teenix.org/educ8.html

cheers

Tony

[teenix]

Hi all,

Still trying to fill in time in the Tanami desert.

In addition to the normal mode of operation, I have added more memory and a new instruction set to the EDUC-8 project giving it a "What If..." mode of operation. Sort of "what if way back then it had..."

In keeping with the 70's era (a bit) it is still not high performance, but it allows much more flexibility for the project with 1K of 16 bit memory, 64 bytes of RAM and 8 bytes of EEPROM, plus 54 new instructions.

The original author mentioned he wanted to create a calculator program for the EDUC-8 but with the 256 byte memory and limited instruction set, that would be a perplexing task to say the least.

I did manage to create a calculator program using the new mode and its operation is based on the HP45 math routines. I scavenged through the code from this calculator and after sorting it out, there were 85 lines of code that do the basic 4 math functions including preformatting of the input data keyed in by the user.

The EDUC 8 instruction clock is way slower than the HP45 so the operation is a bit slow, mainly with divide, but it works ok. The display is scaled down to 8 digits but internally the math is 9.9999999 E+/-99.

I haven't released the new project yet as I am still finding the odd bug in the computer, and the hardware still needs some tweaking but will soon.

cheers

Tony

[teenix]

Hi there,

Almost done, just waiting on some PCBs that make it easy to create the serial Input/Output devices and to test this IO.

I still have the code for the HP97S emulation so will be interesting to see if it connects and works.

cheers

Tony

[EdS2]

I'll be interested to see what the new instruction set is like!

[teenix]

(01-04-2019 07:07 AM)EdS2 Wrote:  I'll be interested to see what the new instruction set is like!

Here's an extract from the help file...

http://www.teenix.org/WIFinsSet.pdf

cheers

Tony

[EdS2]

Thanks!

[teenix]

Hi all,

If anyone is interested I have finally uploaded the complete EDUC-8 project. All the software and hardware seems to work ok with the LED display and keypad serial I/O modules I created.

http://www.teenix.org/educ8.html

cheers

Tony