When I was bright-eyed, bushy-tailed, and just starting out as a junior engineer, I was informed by more grizzled (experienced) members of the profession that switches would finish bouncing by 1 ms, so if I doubled this and worked on 2 ms, everything would be hunky-dory. We did mention this before, but it’s a good question and it’s something with which we all need to be in agreement.
![switch max 4 switch max 4](https://i.ytimg.com/vi/YjLX4qWeIGQ/hqdefault.jpg)
There was also a question from someone as to why we are using 20 milliseconds (ms) as our debounce time. When it comes to writing things down, you should either go with your company or publication’s in-house style or, failing that, write it out the way you say it.
![switch max 4 switch max 4](https://ae01.alicdn.com/kf/H614d02872eb141f68c66aa12e877ddb38/for-SUV-Pickup-Truck-4WD-Switch-4-Wheel-Drive-Button-Selector-Switch-Box-Protective-Case-Cover.jpg)
Others spell it out as “L-E-D,” in which case “an L-E-D” would be the way to go. Some people say “LED” to rhyme with “bed,” in which case “a LED” would be the correct form. Someone else emailed me to ask if it were proper to write “a LED” or if we should use “an LED.” The answer is “yes,” “no,” or “maybe.” The thing is that it largely depends how you say things when you are conversing with someone. However, if really needed, I’ll do it in firmware, especially if the client decided to go with a microcontroller that is heavily over spec’d for the requirements of the project (something that happens far too often). I usually prefer a hardware solution to leave my low-cost microcontroller free to do more important things, in which case a capacitor and resistor is often cheap in terms of cost and board space.
#SWITCH MAX 4 SOFTWARE#
As for the debounce solution, I use either hardware or software depending on the circumstance. It always amazes them when we look at the output from a switch on the oscilloscope. Switch bounce is one subject that some students do have a problem with. software solutions in commercial projects, university lecturer and freelance engineer James Langbridge emailed me to say: My previous column triggered a flurry of comments and questions. Actually, if you’re feeling in a nostalgic mood, you might also want to revisit Part 1 and Part 2, along with my Switch Types and Switch Terminology columns. We also perused and pondered the idea of using an RC network followed by a Schmitt trigger to debounce a single pole, single throw (SPST) toggle switch ( see Part 3).
#SWITCH MAX 4 TV#
Previously, as they used to say at the start of a new episode in a TV series, we discussed the history behind the use of hardware vs.