On 2/3/06, Richard <legalize at xmission.com> wrote:
In article
<f4eb766f0602030407o3dac064amaac33e0f6fb09e0 at mail.gmail.com>,
Ethan Dicks <ethan.dicks at gmail.com> writes:
Two years ago, I built a COSMAC Elf right out of
the pages of the
1977-1978 Popular Electronics articles, on perfboard...
Is the Popular Electronis article scanned online? This sounds kinda
cool! And a nice way to get a little experience without damaging
anything hard to find.
http://www.incolor.com/bill_r/elf/html/elf-1-33.htm
I even used real HP displays (electrically identical to TIL-311s, but
in a different package) and 1822 (5101) 256x4 SRAMs. If you are
shooting for software compatibility without a slavish devotion to the
1976 appearance, you can use a modern 32Kx8 SRAM and even add a latch
to access memory over 256 bytes (but toggling in that much data is
kinda tedious).
You will find it hard to locate a genuine 1861, but Spare Time Gizmos
has a modern 1861 pin-compatible emulator (a shift register, a
counter, and two 22V10 GALs) that fits in the socket for a real 1861.
If you don't care about video, you can get a newer 1802 processor and
run the entire thing at 5MHz.
For those that don't know, there's a reasonably active 1802 group on Yahoo...
http://groups.yahoo.com/group/cosmacelf/
... I'd recommend it if you want to play with the 1802.
-ethan