Chris Chung's TI Datamath and Sinclair Scientific Calculator Emulator Gets a 2020 Makeover
Able to switch between two classic calculator modes on-the-fly, Chung's soldering kit now uses a more easy-to-source display type.
Chris Chung has released an updated version of his Texas Instruments Datamath and Sinclair Scientific calculator emulator, replacing its increasingly hard-to-find bubble-LED display with more common modern LED equivalents.
"This is a new version of my same-named calculator kit. Instead of employing the obsolete and expensive QDSP-6064 Bubble LED Module, this kit employs 3 x 3 digit common 2.5" high LED modules," Chung explains. "This is a microcode emulation, not a function emulation of the original calculators.
"I actually do not understand well the very complex calculator logics. I just implement the the original TMS080x 4-bit MCU and have the calculator ROM run against it. I believe the TI Datamath ROM was obtained from a TI patent document, while the Sinclair Scientific ROM was extracted by reverse engineering a 40+ year old chip via acid bath and microscope analysis."
The original emulation core was produced in 2014, based on work carried out by Ken Shirriff in support of a web-based calculator simulator. Using a specific key combination - C+7 — the calculator can switch between the ROM images for the TI Datamath and the Sinclair Scientific calculator at will, as well as allowing the editing and storing of secret messages and a quick-switch between classic slow and modern fast CPU modes.
Details of the design can be found on Chung's project page, while the source code is up on GitHub. The calculators themselves, meanwhile, are available to purchase for $39 in kit form or $49 fully-assembled from Chung's Tindie store.
