The Apple I Replica: The kit costs $159. The original Apple I sold for $666.66 in 1976.
Many hobbyists are beginning to rediscover the appeal of classic microcomputers from the 70s and early 80s and reproductions such as Briel Computers’ Replica I (based on the Apple I). The Apple I Owners
Club has seen a surge in interest from hobbyists eager to tinker with computers at their fundamental level.
Briel Computers (brielcomputers. com) sells the Replica I assembled ($159), as a kit ($119), or as just the motherboard and specialized chips ($60). Alternatively, the schematic,
PCB layout, and fabrication documents
— enabling you to build a system from scratch — are included with my book on the subject, Apple I Replica Creation.
The Replica I is built around the 6502 microprocessor, the same processor used not only in the Apple I but also in the Apple II, Commodore 64, Atari
2600, and NES. The design has three parts: processor section, video section, and PS/2 interface. ( The PS/2 interface is peripheral and only necessary for those who want to use a PS/2 keyboard. An ASCII keyboard works just as well and can be connected directly to the processor section.)
The processor section is very simple. It consists of the 6502 processor, a 6821 peripheral interface adapter for controlling I/O, a 32KB RAM chip, an 8KB ROM chip, and three T TL chips. All the in/out goes through the 6821. The keyboard provides the 6821 with ASCII input, which it then passes along to the processor. To display text on the screen, the processor sends an ASCII character to the 6821. The 6821 holds the character until the video section is ready and then passes it along (as ASCII) to the video section. The Apple I had no graphics support and was even unable to edit text once it was sent to the video section. The video section served as a dumb terminal. There are hacks to redirect video output so that it goes to a printer or teletype.
The Apple I is about as
simple as an 8-bit micro-
computer can get, and
hacks and projects for
it abound. Larry Nelson
has ported a floating
point BASIC to the
Apple I. Vince Briel
designed a serial
interface card and
has also ported
the classic 70s
game of Star Trek
to the platform.
Grant Stockly
is working on a
reproduction
of the cassette
interface,
which will
allow original
Apple I pro-
grams to
be loaded
from tape.
Others are
investigating the possibil-
ity of replacing the cassettes with an
iPod. Joe Torzewski has scanned hundreds of early
papers. Joseph Carter is looking at ways to bring
graphics to the Apple I. David Cohen is using Apple
I Replica Creation to teach digital electronics to his
fifth grade daughter. Several enthusiasts have built
custom wooden cases to house their replicas. Evan
Koblentz has even connected his Replica I to an LCD
and built it into a custom laptop case.
The Apple I Owners Club (applefritter.com/apple1) serves as the meeting place for retrocomputing enthusiasts. Ideas are exchanged, hardware is built, and software is written. If you’re interested, I hope you’ll join us.
Tom Owad (owad@applefritter.com) is a Macintosh consultant in York, Penn., and editor of Applefritter (applefritter.com). He is the author of Apple I Replica Creation (Syngress, 2005).
References:
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