Don Wilcher has given a classic “microcomputer coach” a severe overhaul by connecting it to a Raspberry Pi Pico — a tool orders of magnitude extra highly effective than the Texas Devices TMS1100 microcontroller round which it was based mostly.
“Lengthy earlier than the Heathkit 6800 microcomputer studying system, the Arduino UNO, or the Primary Stamp, there was Radio Shack’s Science Truthful Microcomputer Coach package,” Wilcher writes in an article for All About Circuits, delivered to our consideration by Adafruit. “Launched in 1985, this easy-to-program package was meant to show customers how microcomputers labored.”
The gadget was impressed by earlier electronics venture kits, which positioned widespread elements on a cardboard structure with spring terminals permitting them to be linked in quite a lot of methods — typically marketed, considerably generously, on the packaging as providing 30, 50, and even 100 particular person initiatives. The Radio Shack Science Truthful Microcomputer Coach took issues additional by capitalizing on then-nascent curiosity in computing, including a Texas Devices TMS1100 microcontroller to the structure and a easy keyboard by means of which it might be programmed.
Marketed as the primary single-chip microcomputer, a tool sort that might later be referred to as a system-on-chip, the four-bit TMS1100 provided a single core, 2kB of read-only reminiscence (ROM), and 512 bits — not bytes — of random-access reminiscence (RAM). To this, Wilcher has one thing a little bit extra trendy: the Raspberry Pi Pico, whose RP2040 microcontroller presents two 32-bit Arm Cortex-M0+ cores operating at 133MHz, 264kB of RAM, and which hyperlinks to an off-chip 2MB flash ROM. Briefly: a supercomputer by comparability to TI’s 1975 microcontroller.
The venture makes use of the Raspberry Pi Pico as a set off for a binary counter, rather than a bodily key press. (📷: Don Willcher)
In Wilcher’s venture, the Raspberry Pi Pico is first constructed right into a standalone digital clock with a relay output. This output is then linked to the coach, which is programmed to behave as a seven-bit binary counter — triggered, after all, by the Raspberry Pi Pico, which is not an easy clock however fairly a pulse supply with adjustable contact pace. Every time the Raspberry Pi Pico sends a set off, the coach reads it as an increment operation for the A-register within the microcontroller.
“As this venture illustrates,” Wilcher concludes, “the classic Science Truthful microcomputer package can simply be resurrected and enhanced utilizing as we speak’s embedded expertise platforms and some digital circuit modules.”
The total venture write-up is obtainable on All About Circuits.
