20 Jan
2004
20 Jan
'04
2:44 p.m.
Holger Veit wrote:
^^^^^^^^^^^^^^^^^^^^^
Tssss. Not to discourage you, but a TTL computer with
bazillions of ICs
is not really suited for newbies, although there is plenty to learn -
namely on those nasty aspects like circuit timing, delays, glitches,
noise on power and signal lines. TTL is to a large degree analog, not digital,
circuit development ;-)
So are TUBE computers better?
You might not directly want to start with a monster
like Computer 74 or
EGO, but perhaps with a simple ALU/register device: get a 2901 circuit
from BG-Micro and play a bit with it (a breadboard with lots of switches
and LEDs is sufficient). And then extend it with a 2909/-10/-11 from the same
source and build the micro control for that toy. This is already the
basic step towards an own homegrown system.
Using LS TTL ( also from BG-MICRO ) I expect I'll need about 32 chips
for a 12 bit ALU and 32 chips for basic control. I suspect about the
same for front panel logic. Since I don't have a PROM or PAL burner
a bit slice design out of the question for me.
Ben.