RAM storage in early Texas Instruments calculator chips #VintageComputing #DieShot @kenshirriff
Ken Shirriff tackles reverse engineering RAM storage in early Texas Instruments calculator chips, from DRAM to CMOS:
Texas Instruments introduced the first commercial single-chip computer in 1974, combining the CPU, RAM, ROM, and I/O into one chip. This family of 4-bit processors was called the TMS1000… This microcontroller was also used in hand-held games and simple control applications such as microwave ovens. Since its software was in ROM, the TMS1000 needed to be custom-manufactured for each application, but it was inexpensive and sold for $2-$4 in quantity. It became very popular and was said to be the best-selling “computer on a chip”.
In the TMS1000, code and data even have different sizes: instructions were 8 bits and stored in a 1-kilobyte ROM, while data was 4 bits and stored in a 64×4 (256-bit) RAM. Since the space for RAM was limited, Texas Instruments developed new circuits for RAM: Dynamic RAM.
In 1978, TI began building CMOS calculator chips, starting with the TP0310 and TP0320 chips. These chips were used in calculators such as the TI-30-II.
TI also used CMOS to implement “Constant Memory™”, preserving calculator data even when the calculator was off; CMOS’s low power consumption meant that the memory could be continuously powered without draining the battery.
Eink, E-paper, Think Ink – Collin shares six segments pondering the unusual low-power display technology that somehow still seems a bit sci-fi – http://adafruit.com/thinkink
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.