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HomeIoTReinhard Grafl's Single-Breadboard Laptop Packs Eighties Expertise Right into a Tiny 5-Chip...

Reinhard Grafl’s Single-Breadboard Laptop Packs Eighties Expertise Right into a Tiny 5-Chip Footprint

Classic computing fanatic and {hardware} engineer Reinhard “c0pperdragon” Grafl has put collectively a MOS 6502-based pc with a distinction: your entire factor suits on to a compact breadboard and makes use of solely 4 built-in circuits plus a crystal oscillator.

“Designs for SBCs [Single-Board Computers] based mostly on the [MOS Technology] 6502 are fairly frequent, however usually they use some specialised ICs [Integrated Circuits] to deal with the IO [Input/Output]. I did some designs myself utilizing customary 74-logic for the auxiliary performance,” Grafl explains. “Pushing the minimalist method to the acute, I made a decision to discover a solution to match a 65C02-based pc into 5 ICs together with oscillator, CPU, RAM and ROM.”

Earlier than setting about constructing the surprisingly compact machine, Grafl set himself 4 key specs: it had to have the ability to run a WDC 65C02, a contemporary incarnation of the basic MOS 6502, at 10MHz; it needed to embody 32kB of RAM; it needed to provide 32kB of ROM storage; and it wanted to make use of software-driven IO, to cut back the element rely. Oh, and it wanted to suit right into a single BB630 breadboard.

“The BB630 board is large enough to suit the necessary CPU/RAM/flash ICs and one extra small IC,” Grafl explains. “This extra IC has to one way or the other implement all he crucial logic for each the reminiscence addressing in addition to for the IO. A quad two-input NAND (74HC00) is a reasonably versatile possibility right here. Some very slender areas between these ICs can be utilized for a little bit of analog circuitry.”

For these seeking to construct their very own Grafl has uploaded KiCad challenge information for the SBC, together with a schematic and a proposed PCB design, to GitHub underneath an unspecified open supply license, together with a short demonstration utility. “I do not indent to do way more programming on this machine,” Grafl admits.



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