In this context, the usage of words meaning "open" and "closed" varies between languages -- with contradictory interpretations! For example, a switch that is "closed" to a French speaking person will be described as "open" by an English speaker. Most of our multi-lingual members will be aware of the issue. In case of any doubt, here's a diagram for clarification and as a mnemonic.

-- Jeff

_________________
In 1988 my 65C02 got six new registers and 44 new full-speed instructions!
https://laughtonelectronics.com/Arcana/ ... mmary.html

Avoid the doors!

(I still sometimes have a little difficulty because of the way poly crosses over active. The eye is drawn to follow the poly. But the conductive channel underneath the gate crosses from one area of active to the other. So, the transistor's "length" is the width of the poly, and the transistor's "width" is the direction along the length of the poly. I just have to think about it. The width and length are sufficient to figure out the strength of the transistor, but for purely digital purposes the strength is irrelevant. It affects timing and it affects some circuits which are not strictly digital.)

Cheers
Ed

(I had no idea about that French usage, Jeff!)

I think I'm sticking to the door analogy for now. Posted this on the talk page:



I also added the following disclaimer to the article:



I hope that's satisfactory.



If the "door" is aligned to let things through the gate, won't these correspond to the width and length (depth) of the door though?

Hmm. If you were making up your own terminology and analogy to explain something, then anything which helps comprehension is fair game. But in a technical field with pre-existing terminology you're addressing a near-term puzzle at the expense of the longer term: your local conventions cause confusion when talking to someone with experience.

Because "gate" is already an overloaded term - boolean logic gate versus gate terminal on a FET - I advise against using it also to mean a transistor. It's transistors that we have here. We can call them FETs if that helps, but it probably doesn't.

"The channel forms and the transistor conducts when the gate is high." That's unambiguous and terminologically correct. "The switch is closed to make the circuit, it's open to break the circuit." That's good too.

Speaking of a transistor as "on" seems forgiveable to me (I'm sure I've said that many times) and it matches everyday experience when we speak of a lightswitch being either on or off.

I really do advise avoiding the door analogy: it's unique, and is leading you away from common practice.

Cheers
Ed

Ok, I'll see what I can come up with.

Just added a section on adders btw.

By the way, if you think there's some terminology I ought to cover in any of the sections and might be unaware of, then please tell me.

What's a good verb form if using on/off terminology, for e.g. "...a new value can be copied into the latch by opening the w400e gate"? Does "enabled" work, or will it need some rephrasing?

Is w400e a gate, or is it in fact signal, which drives the gate of an (unnamed) transistor? The single-transistor dynamic latch is an absolute staple of design in NMOS, so it would be best to describe a latch (which has an "enable" input) and then to say that this is an example of a latch. I think I'd say "a new value is loaded into the latch when the enable signal is high", or something like that.)

When describing the latch, one might say that the input signal is gated by the pass transistor. A new value is loaded when the pass transistor is on. Again, pass transistors are a staple of NMOS design, and as they can be bidirectional it might be wise to describe them separately. It may be that outside the CPU core there are no examples of bidirectional pass gates on this chip. [Hmm, I said gates to mean transistors]

In any event, IMNSHO "opening" a gate is forbidden terminology!

Cheers
Ed

p.s. FWIW, Wikipedia contains the phrase "the enhancement-mode device is equivalent to a normally open (off) switch" which perhaps shows the need for disambiguation.

I've now rewritten the article to avoid the door analogy. The relevant diff is at http://wiki.nesdev.com/w/index.php?titl ... oldid=6623 . w400e is indeed a signal, and I made things a bit clearer by not equating it with the gate.

And you guys think I'm pedantic!

_________________
x86?  We ain't got no x86.  We don't NEED no stinking x86!

I've now added shift registers and rephrased the PLA section in terms of decoders and mask ROMs after feedback from lidnariq and Quietust (who made the Visual 2A03 and 2C02 sims).

The user's guide would probably be a good place to link the article (as anyone who wants to do more than look at the colors is bound to go there), and maybe from some other place on the wiki where it's easy to find too.

That sounds like very useful feedback! I wasn't aware of the visual 2c02.

I've added a sentence to introduce your link, on the visual 6502 user guide which as you note is a landing page. And again on the front page.

Cheers
Ed

Great, thanks!