Self-confessed “electronics nerd” Dhruv Wadhwa has designed a handheld pc on a prototyping board, powered by a Raspberry Pi Pico and providing a retro bit-by-bit programming course of impressed by front-panel programs just like the Altair 8800.
“[It’s] an eight-bit handheld pc emulator impressed from Ben Eater’s breadboard pc and [the MOS Technology] 6502 processor,” Wadhwa explains of his creation, which owes a lot to the very first days of private computing. “The hand held pc incorporates the Raspberry Pi Pico in addition to push buttons, an OLED display screen, and an IMU [Inertial Measurement Unit].”
Impressed by machines just like the Altair 8800, this handheld emulates an eight-bit microcomputer with bit-by-bit programming. (📷: Dhruv Wadhwa)
Whereas immediately most computer systems are programmed in high-level languages, written comfortably with a keyboard in a feature-packed Built-in Growth Atmosphere (IDE), that wasn’t all the time the case. Early computer systems had been laboriously programmed bit-by-bit, actually, by stepping by means of the reminiscence and flipping front-panel toggle switches to alter zeroes to ones or vice-versa.
That is precisely how Wadwha’s unnamed creation is programmed — albeit utilizing push-buttons and in a much more compact, pocketable type. “It has two modes: PROG mode and RUN mode,” Wadhwa explains. “In program mode, you could journey by means of the entire RAM areas and edit their contents, permitting you to program it. The run mode shows the values of various CPU modules akin to A and B registers, program counters, flag registers, and so forth. It has a clock and a reset button. Urgent the clock button as soon as single-steps the pc, and preserving it down runs the clock indefinitely.”
The board’s wiring is a combination of naked wire buses, solder blobs, and flying leads. (📷: Dhruv Wadhwa)
One tip to modernity, apart from utilizing the Raspberry Pi Pico and its RP2040 microcontroller to emulate a easy eight-bit processor and its peripherals, is the show. In addition to displaying the present reminiscence location and its contents, rather than the LEDs or lamps historically used, it updates continually in run mode — offering a glimpse at precisely what the processor is doing.
Extra data on the challenge is obtainable on Wadhwa’s Hackaday web page, whereas an emulation of the emulator is obtainable on Wokwi for interactive use. The supply code, in the meantime, has been revealed to GitHub underneath an unspecified open supply license.
