IEEE Spectrum’s Stephen Cass has saved a traditional transportable pc from the scrap heap due to some intelligent upcycling, turning a damaged TRS-80 Mannequin 100 into an Arduino Mega 2560-powered customized terminal.
“How laborious might or not it’s to swap out a 40-year-old 8-bit 8085 CPU and motherboard for one thing extra trendy,” Cass asks, rhetorically, in a retrospective of the work carried out on his challenge up to now — work which is ongoing with a view to finally construct the system as much as a contemporary multi-core Linux field.
With a useless TRS-80 on his desk, Stephen Cass set about upcycling it into one thing mixing classic and trendy options. (📷: James Provost/IEEE Spectrum)
The reply: moderately laborious, in case you’re trying to retain the unique LCD panel, which sits above the transportable’s keyboard to supply what was at its launch in 1983 an impressively-capable system for computing on-the-go. “The M100’s LCD is actually 10 separate shows, every managed by its personal HD44102 driver chip,” Cass explains. “The driving force chips are every accountable for a 50-by-32-pixel area of the display screen, besides for 2 chips on the right-hand facet that management solely 40 by 32 pixels.”
Utilizing a useful service handbook, the HD44102’s datasheet, and different classic computing fans’ efforts in the identical subject, Cass was in a position to join the LCD to the Arduino Mega and show arbitrary photos — turning the Arduino into, successfully, a monochrome show driver accepting bitmap inputs and formatting them as required.
“The LCD can now be hooked as much as the microcontroller of my selection by way of a parallel or serial connection to the Mega, which copies incoming knowledge to the framebuffer,” Cass explains. “I intend to make use of a Teensy 4.1, which can permit me to speak to the matrix keyboard straight, have sufficient compute energy for some fundamental text-editing firmware, and supply a VT100 terminal serial interface—which may very well be to a Raspberry Pi 4 Compute Module additionally mounted contained in the [Model 100]. That would offer Wi-Fi, a 64-bit OS, and as much as 8 gigabytes of RAM—a giant step up from the 8 to 24 kilobytes that the case initially housed!”
The long-lasting TRS-80 Mannequin 100, which constructed on Kyocera’s Kyotronic 85 design, has impressed a variety of successors together with the DevTerm. (📷: Gareth Halfacree)
Overhauled or re-imagined TRS-80 Mannequin 100s are a standard sight within the maker world: 4 years in the past Trammell Hudson , and like Cass reused the unique show by some intelligent coding, whereas pseudonymous maker “belsamber’s” tackle the improve able to working two full-width terminal side-by-side. The core TRS-80 design, in the meantime, has impressed units , now obtainable , to .
Cass’ full write-up, together with hyperlinks to the service handbook and different assets, is offered now.