How to show negation in a label?

Schematic
1

I want to show a global label name with negation (that it is active low). It won’t let me use a leading ‘/’ in the name. Is there a trick to this? Or is there a way to show a bar above the name? How is this normally handled?
Thanks for any suggestions,
Lloyd

2

Use the ~ Symbol. And use it again to terminate if you need a partial

4 Likes
3

Thanks Naib. Worked like a charm.
Lloyd

5

In software, a variable that is true when low, has the suffix -F

So you might use a label like ABC-F

6

Thanks for the suggestion but I prefer the bar over the name with ~ as suggested above.

7

for firmware, we prefer a _b suffix but its the same principle just different implementation

8

Since I have never seen that in 30 years of writing software, I am going to ask “citation needed”. :slight_smile: Hyphen is also not valid in identifiers in most languages.

Now, if you said “in some software I worked on” then it might be true.

9

According to wikipedia : https://en.wikipedia.org/wiki/Logic_level

The name of an active-low signal is historically written with a bar above it to distinguish it from an active-high signal. For example, the name Q, read “Q bar” or “Q not”, represents an active-low signal.

The conventions commonly used are:

  • a bar above (Q)
  • a leading slash (/Q)
  • a lower-case n prefix or suffix (nQ or Q_n)
  • a trailing # (Q#), or
  • an “_B” or “_L” suffix (Q_B or Q_L).[1]

[ Unfortunately the overbars in the original text did not replicate here]

_B stands for “bar”, and _L for “low” I guess ?

10

Ha! I learned -F back in the assembly language days of 6800. 6502, 8051…

11

To what does “-b” refer?
That might be confused with bit, byte, binary.
“-F” indicates true when low (normally false)

12

That isn’t really an issue for firmware

13

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