Solderless breadboarding (was: Re: HP-IB, Amigo/cs80 was Re: hp 9153 floppy & disk)

Joachim Thiemann joachim.thiemann at gmail.com
Wed Feb 17 19:19:17 CST 2010


On Wed, Feb 17, 2010 at 13:49, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
> The main problem is that those breadboard are terrible. It's not the
> clock speed that matters, it's the swtiching time of the IC. Most modern
> ICs have ouptus that switch so fast that when you combine them with the
> stray capacitances on the breadboard and the relatively high impedance
> power connections, you get power and ground lines bouncing all over the
> place. Without a _good_ 'scope it's impossible to know why your circuit
> doesn't work. If you stick to 4000 series CMOS you'll be alright, but
> modern 74xxx familes are pushing it. Really pushing it.

But if you're just learning high speed don't matter, even with full
computer prototypes.  Incidentally, I just saw this:
http://blog.makezine.com/archive/2010/02/building_a_cpm_68k_computer_from_sc.html

Crazy, but I'm cheering for him! Retrotastic! :-)

Joe.

-- 
Joachim Thiemann :: http://www.tsp.ece.mcgill.ca/~jthiem



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