Apple 1 Mimeo Project
Portions of a
Mimeo 1 Motherboard and an
Original Apple 1 Motherboard side by side
(this image is not altered or created with photoshop or other
image editing software)
The Apple 1 Registry -
information about original Apple 1 computers
Vist my blog for
updates on my latest work on the Apple 1 and other projects
My Apple 1 Keyboard Solution
Finding ASCII keyboards for your Apple 1 project can be difficult.
lets you connect readily available PS/2 keyboards,
to your vintage computer that expects a parallel ASCII type
The included serial interface also allows you to download
software quite easily into your Apple 1.
websites with Apple 1 or related info:
and a user forum (maybe the only Apple 1 specific forum in
Images, documents and a recently wirewrapped Apple 1 prototype
lot of good stuff including some theory of operation
John C.'s Apple 1 blog - his Apple 1 clone projects (including a
Mimeo) and much more info on the original Apple 1
Coopers Apple 1 site. See his Mimeo PCB based replica using
vintage chips scrounged from around the world
W Sander's beautify repackaged original (includes some programs for
download to cassette interface from an iPod)
Jeff Tranter's blog has a lot of useful mods and experiments that he
has done on his replica 1.
Using Later Generation Technology:
Vince Briel's original
Another version made in Europe
Mass Storage and expansion:
Solves your mass storage issues without dealing with a tricky
Don Lancaster's TV Typewriter
The video section has similarities to the Apple 1, and several
have speculated that Steve W. leveraged the TVT design in putting
together the video section of the Apple 1. Here is Steve's
to my inquiry to him about this.
are a several people, including myself that has speculated that
leveraged and enhanced Don Lancaster's TV Typewriter video system
developing the Apple 1. I know you were also involved in
games to some extent, at the time. Can you comment on any
existing designs that might have helped inspire the rather clever
system on the Apple 1?
Thanks and regards,
was totally unaware of Don Lancaster's TV Typewriter when I
TV Terminal to access the Arpanet. I only found out about
device in subsequent years. Our designs had to be very different.
sure that both schematics are online so anyone could see this. I
a microprocessor and RAM to this terminal to create what became
did a lot of great and important stuff back then. But I wasn't in
discussion loop or Popular Electronics loop so I would not have
known his name.
Apple I video system was designed with synchronous counters for
television horizontal and vertical signals. They were probably
identical to the ones I'd designed in to my Pong and Breakout
an early phase in my life I tried to minimize chip count. But by
time I tried to minimize chip area, with smaller chips winning
even when there were more of them, in many cases.
I also looked for the absolute
major cost component of my TV Terminal was the video RAM. I chose
columns of text per line on the screen to match NTSC bandwidths.
characters would have meant that the dots forming them might not
on NTSC TV's. I chose 24 lines of text, giving 960 characters. I
why I didn't use 25 lines but maybe it took an extra chip of
decoding. It still would have fit into the 1024-bit dynamic shift
registers I chose for the screen memory. These 1024-bit dynamic
registers were the most cost-effective solution I could find for
screen memory and they were tiny 8-pin chips. These RAM's had to
once for each character on the screen. Since the screen was drawn
60th of a second, it meant that any character only appeared 60
second. This also led to only being able to add one character
60th of a second, which is much lower than microprocessor speeds.
this terminal would ONLY connect over a modem and high-speed
then were 300 baud, or about 30 characters per second. That's how
tightly optimized this design was.
I turned it into the Apple I by adding my own local processor and
the low character refresh rate was a real slow-down. But I was
modifying a terminal to get something built quickly.
Apple ][ only took about 3 months to design and it was a computer
the ground up, so it wasn't held back by having been a
a TV terminal designed for low cost with modem connection. Oddly,
Apple ][ wound up with about half the parts doing 10 times as
that was due to other things that really couldn't have been
easily when I designed my TV Terminal.
I hope this doesn't confuse you.