Development of a transputer ISA board

Development of a transputer ISA board

I developed software for transputers in the years 1993-1996. A few months ago, I wrote some articles about my experiences, and most recently I developed a transputer emulator in Javascript

After my transputer emulator in Javascript was working, I got curious about running my software on a PC computer. I have several PC motherboards with ISA connectors, and I decided to build a card compatible with the Inmos B004 (a single board to test transputer processors). Out of curiosity, I decided for compatibility because I wanted to run the Inmos Occam compiler.

A quick look in eBay and I got two transputer boards (TRAMs) for $25 each one. Both based on the Inmos T805 transputer running at 30 mhz.

I got the port numbers for the board from Geekdot , and designed a decoder schematic based on TTL circuits.

My first schematic for the board. My first schematic for the board.

The TRAM board contains the transputer and its memory. It is connected to the ISA board with an Inmos C011 chip that serializes and deserializes the communication link. This chip is accessed via the ports 0150H-0153H. My ISA board also provides a 5 mhz oscillator, two flip-flops to reset and analyse the transputer, and a tri-state gate to read the error status.

Ports of an Inmos B004 board Offset Field 0150H Read Receive data 0151H Write Send data 0152H Read Receive status 0153H Read Send status 0160H Write Latch bit 0 = Direct to Reset 0161H Write Latch bit 0 = Direct to Analyse 0160H Read Bit 0 = Direct from notError

I required a single ISA board drilled for homebrew development. I was going to buy one board in eBay for $35 dollars shipped, but I considered it was way too expensive. After some searching, I found the PCBWay showcase, where this same board was available for sale. And better, I could get 5 boards of 10x10cm. for $25 dollars shipped.

... continue reading