The transputer chips designed in the early 1980s were and still are odd beasts. It has hardware support for processes (hence OS in hardware, well, sort of), and its assembly language is such a pain that Occam is a much better way to program it. It’s a language that is close to the hardware and allows parallel processing to be built in at a basic level. They have four fast (for the time) 10mbps (20mbps later) links that are used to communicate between devices and other systems.
The only real downside is that the chips were expensive, so they never really made it into common usage in embedded applications. Quite a few parallel processing systems using transputers were made, though.
The Black Rock Blog looks into interfacing and emulating Transputers using the RP2040 chip on the Raspberry Pi Pico:
While I was looking at the RP2040, it suddenly occurred to me that the four links on a transputer could be implemented using the eight PIO state machine son an RP2040. Each state machine handles data in one direction, leaving the processor(s) free for other work. What other work? Well, how about running an emulator of a transputer on the core? That would give you a hardware emulation of a transputer.
There are some interesting videos explaining how this might happen below. The article talks about things in detail.
- Picoputer Part 1: What is a Transputer?
- Picoputer Part 5: It Gets More Complicated
- Picoputer Part 6: Real Transputer Hardware