Normalization in a Lunetta solution?

bingmachine · Joined: Jan 23, 2009 Posts: 19 Location: Sweden

Hi!

I've just started reading about these Lunettas and I feel very inspired by the whole idea. So I'm planning a Lunnetta-in-a-box-sort-of-thing and I'm thinking about the possibility to normalize some connections.
The obvious thing to do is of course to add pull-ups or pull-downs to all inputs, which is even required for most logic inputs. And I suppose that could be thought of as a sort of normalization. Say 100k to ground.

But what about also adding something like 1k between the inputs of a 2-input NAND? So that it could be used as an inverter without the need of any extra wires? Is that a good idea?

And what about output resistors? Are you guys adding some kind of short-circuit protection like that?

/Erik Forsling

slacker · Posted: Sat Jan 31, 2009 4:51 am Post subject:

There's some good info on normalisation in this thread
http://electro-music.com/forum/topic-23951.html.

What I'm doing with my lunetta is experimenting with the chips on the breadboard to figure out which pins I want to normalise and which one are fine floating. So far I've just added pull up/down resistors to things like reset , enable or inhibit pins so that I don't have to plug things into these to get the chip to work, but they can be used if I want to.

For NAND and XOR chips if you use pull up resistors on both the inputs, then if you just use one input it works as an inverter.

I haven't used any sort of short circuit protection and I haven't killed anything yet.

bingmachine · Joined: Jan 23, 2009 Posts: 19 Location: Sweden

Thanks for the input, and thanks for pointing out that thread to me. Good reading.

Good point about HOW to normalize simple gates as well. Should have thought of that.

However, I'm starting to think I might want to normalize even some connections BETWEEN ICs. Say e.g. the outputs of a 4-bit counter into a 4-bit adder, or something like that. But I will have to think about that later.

Back to the breadboard!

Thx!
/Erik

Rykhaard · Joined: Sep 02, 2007 Posts: 1290 Location: Canada

I myself am following the protection principles from my normal modular world. Where required, diodes to prevent negative voltages to harm any of the CMOS chips; 100k to Ground or Positive where required and 1k to the required outputs.

I'm doing all of this, as my Deathlehem Machine WILL be interfacing with my normal modular, in the very near future. (Actually - the 1st and last mp3 that I recorded, WAS sent through a mixer on my normal modular.)