A simulator for the OBP space flight computer #Space #VintageComputing @hjalfi
David Given has coded an assembler and simulator for the OBP, the On-Board Processor used by a variety of spacecraft, designed way back in 1968.
The OBP is a rather elegant 18-bit, two’s-complement machine from about 1968. It’s a full Von Neumann architecture with code and data living in the same address space, of which there can be up to 64kw, divided into 4kw pages. The instruction set includes hardware multiplication and division, multiple-bit shifts, a decent set of comparison instructions, system calls, simple memory protection, rich I/O including DMA, and sixteen different individually maskable interrupts — it’s actually quite a nice thing to work with. Admittedly, running at 250kHz and with most instructions taking multiple cycles, it’s not the fastest thing around. But then it did use non-volatile core memory and was built out of raw NOR gates.
The OBP was used on a variety of spacecraft, including the OAO-3 Copernicus space telescope, which was in operation from 1972 to 1981.
Adafruit publishes a wide range of writing and video content, including interviews and reporting on the maker market and the wider technology world. Our standards page is intended as a guide to best practices that Adafruit uses, as well as an outline of the ethical standards Adafruit aspires to. While Adafruit is not an independent journalistic institution, Adafruit strives to be a fair, informative, and positive voice within the community – check it out here: adafruit.com/editorialstandards
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.
Have an amazing project to share? The Electronics Show and Tell is every Wednesday at 7pm ET! To join, head over to YouTube and check out the show’s live chat – we’ll post the link there.
