The Resurrection of the Apple II Plus: A Hardware Clone Wonder
In the realm of retro computing, aficionados frequently turn to software emulators to experience classic devices anew. Nonetheless, one ambitious initiative has embraced an alternative route by reproducing the Apple II Plus via hardware integration, moving away from emulation. This endeavor illustrates how, through innovation and commitment, the legendary Apple II experience can be reinvigorated with contemporary technology.
Reconstructing History with Present-Day Components
The project, spearheaded by Simon Boak, presents the SB Mini II, a “Homebrew Apple II Clone” that restores the Apple II Plus’s hardware using modern parts. By utilizing available fundamental logic chips and the renowned 6502 CPU, Boak carefully devised a blueprint with the guidance of original circuit schematics and a vast array of literature on the topic.
Updating the Apple II Plus
In the initial Apple II, dynamic RAM (DRAM) was utilized to control expenses. Yet, technological progress has made Static RAM (SRAM) a feasible option. The SB Mini II incorporates one and a half 32K SRAM chips to achieve the requisite 48K memory. This transformation eliminates the requirement for extra circuitry to refresh the DRAM, optimizing the memory function.
Video output has also been enhanced. Rather than producing a composite video signal through complex circuitry, the initiative employs an Apple II VGA card, delivering clearer video output and simplifying the circuit architecture.
Technical Breakthroughs in Timing and Input
Timing signals have been improved in this contemporary clone. A 4.096 MHz crystal oscillator, divided down to 1.024 MHz, effectively simulates the original’s 1.023 MHz clock speed. This accuracy guarantees the clone operates with the same timing integrity as the original Apple II Plus.
A Raspberry Pi Pico boosts the project by enabling USB keyboard connectivity. The Pico generates identical parallel data signals as the original keyboard, eliminating the need for voltage level shifters and making user interaction more straightforward.
Designing the Ideal Case
The project concludes with a bespoke 3D-printed case inspired by the Apple ProFile hard drive design. This case, featuring additional vents and a rear panel for connections, allows the internals to remain accessible without tools, reflecting the original Apple II’s user-centric design. Boak has also created a matching Studio II LCD monitor to finalize the setup.
From Apple 1 to Apple II Plus: A Legacy of Recreation
Simon Boak’s contributions do not stop at the Apple II Plus. In June 2024, he successfully duplicated an Apple 1 with a printer that employed an SD card for storage. Such initiatives highlight the commitment and creativity of vintage computing enthusiasts, demonstrating that hardware reproductions can provide experiences as genuine as those facilitated by emulation.
Conclusion
The recreation of the Apple II Plus through hardware integration showcases the passion and inventiveness of the vintage computing community. By merging modern components with classic designs, this project not only safeguards the heritage of Apple’s early innovations but also motivates future pursuits in retro computing.
Q&A Session
Q: What sets the SB Mini II apart from a software emulator?
A: The SB Mini II is a hardware clone utilizing modern components to replicate the Apple II Plus experience, whereas emulators simulate the experience through software exclusively.
Q: Why was SRAM selected in place of DRAM for this project?
A: SRAM was chosen due to its newfound affordability and its elimination of the need for circuitry to refresh DRAM, simplifying the design.
Q: In what ways does the video output differ from the original Apple II?
A: The project incorporates an Apple II VGA card for improved video output, removing the requirement for intricate video generation logic.
Q: What function does the Raspberry Pi Pico serve in the clone?
A: The Raspberry Pi Pico connects a USB keyboard to the Apple II, producing the same data signals as the original keyboard and eliminating voltage level shifters.
Q: How does the case design improve the clone’s usability?
A: The 3D-printed case facilitates easy access to the internal components without tools, adhering to the original design’s focus on user-friendliness.
Q: Has Boak been involved in cloning other Apple products?
A: Yes, Boak previously created a replica of the Apple 1 with an integrated printer and SD card storage.
Q: What motivated the case design for the SB Mini II?
A: The case design is inspired by the Apple ProFile hard drive, featuring additional vents and a back panel for improved connectivity.
