The Inmos Transputer
The Transputer is a high-performance microprocessor (manufactured by Inmos UK) possessing two special features:
- four on-chip DMA serial communication links: these are independent of one another, and also independent of the processor (ie, they can send while the processor is busy executing instructions)
- hardware support for parallel programming: the transputer features a microcoded scheduler that shares processor time between concurrent processes (in a round-robin scheduling scheme), and two priority levels for processes.
Also featured are two built-in timers and fast on-chip RAM. (It is readily apparent tha the Transputer was designed with embedded control applications in mind.)
The serial communication links are used to connect several transputers in a network (as shown in the figure). The result is a MIMD-parallel (Multiple-Instruction, Multiple-Data) system. Since the system has distributed memory, transputers use a message-passing protocol to exchange data.
The Local Setup
Hardware
The transputer hardware used for this project consisted of:
- A Transtech TMB-16 motherboard with a 16-bit PC bus interface, and space for 10 Dual-In-Line Transputer Modules (TRAMs).
- two T805 transputers (30MHz and built-in FPU):
- "T1": 4MB RAM
- "T2": 1MB RAM
- A/D converter: Sunnyside Systems adt108C
- 12 bits
- 100 kSamp/sec
- 16 differential inputs
- D/A converter: Sunnyside Systems dat208
- 12 bits
- 50 kHz max output rate
- 8 single-ended outputs
The following figure illustrates the placement of each TRAM on the motherboard, and gives an indication of the size of each module:
Possible Topologies
The TMB-16 motherboard contains an Inmos C004 reconfigurable link crossbar switch, which can be used to connect the existing TRAMS in many different topologies. There are two topologies possible with our current setup: the pipe and the tree:
Configuration of the C004 crossbar switch is accomplished through a program (Inmos' Network Configuration Software, (NCS)), which is run when the PC boots. The tree topology is being used with all current software: the "T1" transputer functions as the "root" processor, communicating with the PC host, while the "T2" is the "slave", in charge of doing most of the control calculations.
References
- INMOS ANSI C User Manual
- INMOS Transputer Databook
- adt108C A/D TRAM User's Manual
- dat208 D/A TRAM User's Manual