Building my own interface.

The Transputer system fascinted me very much. After that moment I have contact with this man about the Transputer system. And later he aquire more Transputer board’s and i could borrow some. But my problem was that I have NO interface between the Transputerboard’s and a PC so I decide to build one by myself.

In the handbook of the CSA ISA to Transputerlink interface, Transputer Education Kit User Guide, I found a schema of the CSA-Transputer interface. This circuit around the IMSC012 would I build. Instand of the IMSC012 I bought the IMSC011 IC’s with could have the same function and even more. Together with some TTL-ic’s the project come to a nice print.

From the Transputer Education Kit User Guide, CSA.

I connect my IO-Print to the Transputer and start testing my interface. With the famouse 24 byte [Who-you-are program ?] i get as answer AA AA 00 00 back. This is a 32 bit Transputer !! It is working.

Next step is the Mandelbro program, but when I want to run this at 60 % of the picture the program stop’s.

Mandelbrot stops around 60 %

Why ???

Each time I start the Mandelbrot I have the same result. Each time !! This point take me a lot of time to find the problem. After a couple week’s a call my friend with the originel CSA-Interface and I could borrow his system to compare this with my selfbuild system. I use the originel CSA IO interface in my IPC system, use the good working program. At the end I start swapping IC’s between the original CSA IO interface and my self build interface. After a lot of debugging and swapping IC’s i found there was aq new 74LS245 withs was wrong ?? At low speed it was working Oke, but at high speed I get a lot of problem’s. Al the 10 new buy pieces were wrong. So i take a look in my storice and found a old 74LS245. Thisa one works very good so I am happy.

ISA-interface testing

Conclusion: even new IC’s could be wrong.

The Transputerboard I use is a Caplan board with 2 T800 Transputers with each 2 Mb memory.

Now I have a selfbuild ISA to Transputer link interface with is working good. Next step is I to understand the propgram’s, how to program and wordt with OCCAM an the Transputer.

As a member of the Dutch Hobby Computer Club, the section Retro Computers ( sorry, dutch only) I visit almost there meeting’s. Last meeting at 27 September 2017 we talk a lot about the Transputer systems. We planned to go to work with 4 people at the Transputer system’s. Talking, thinking, study, programming and working. So I am not alone.


How I become intrested in Transputers.

A couple years ago I visit a meeting of the Hobby Computer Club te Hooglanderveen te Holland (The Netherland’s). This was the Artificiel intelligence user group. An person have a question about a system. He want to work with Transputers. He has a ISA-I/O cart for a PC. This cart was a bridge between a program under DOS to a serial link to a Transputer System. He has problem’s to get his ISA-cart working.

I know that I have at home some “old” PC’s with a ISA-slot in it. That PC’s are running under W98 and DOS. So I told this to hime and we talk together about his problem. He want to run some program’s on a PC, connectes by the ISA-interface to his Transputer board’s.

I took his CSA ISA-interface and a copy of the installation book at home and a couple week’s later I have install the ISA-interface include the necessary software. This was the first time a come across a Transputer system.


A Transputer is a vintage computer system build arount 1985 to 1995, invented by INMOS, an company from Bristol, UK. The Transputer has 4 I/O links for communication between Transputers so you can build big Transputer processor networks to distrubuted your program so your problem can be solved by many processors. So you can split your task in smal part’s. Together with the Transputer hardware INMOS construct the language OCCAM, special for parallel programming.

Around that time this hole system was a big invention and was to call: the poor man’s CRAY. A lot of computerpower for a reasonable prise.


Picture from website:


RC2017/10, Work with Transputers.

Last month’s was a very busy time. I have a lot of job’s to do at home, for work and church.  Also I have made some time for my new project. Make myself familiar with Transputers.

This is also the goal for this month: “Work with Transputers, try to understand how the system is working.”

I have build a ISA to Transputer-link interface. Let’s go to start to work with it.




End of RC2016/10

This evening some people of the local hackerspace “B+ Westland” visit my place to look at the 4004 project. We have study some assembly code for the 4004. This was very nice.


We have look at the result of my project and we have also study some other project’s from other people.

This is the end of the RetroChallenge 2016/10. I wish I have more progress the last month, but I am still happy with the result. This week I go to make/finish some little program’s to do the challenge for the Roborama-game’s of the Dutch Computer Club next weekend.

Here is my goal not to win, but to do the challenge.







Keep moving the Intel 4004

Last week i have a very little time so I couls only make some little progress. I have program some little routine’s for the 4004 processor in assembly to make some little demo’s


Next week I hope to have some more time so I can work on some bigger programm’s. With this bigger program’s I could run the Roborama challenge on November 5 2016.

I have so much to do in so less time !!

But, during this Retrochallenge 2016/10 I have a lot of fun. Working with the assembly for Intel 4004 processor is a nice challenge for my. I keep going during the next couple month’s.

I would thank’s the organization of the Retrochallenge to motivate me to work on this project.


Working in 4-bit’s

It’s a nice challenge to program the Intel 4004 processor. All the registers and accu are 4 bit wide. So when you want to make a little delay I need at least 4 register’s to create a nice wait-delay. This hole weekend I study and work at my program with a couple of subroutine’s.


I make a lot off progress and hope I can finish next weekend the main program to run 2 or 3 challenge’s for the Roborama game’s on 5 November at the Robotica club.

Happy Programming the Intel c4004 !


Coding the Intel 4004 processor

More and more I learn about the assembly code for the Intel 4004 processor. It is fun to work with it. Also it is a little bit complicated because I am not a very good programmer. But I make slowly progress.


First I make some note’s on paper, later I make some little test program’s and then I try to connect those little parts together to the right program.

Time, time and time. This is what this progress cost. But it give’s also a lot of fun. So I keep going.