Just have to say I've enjoyed your blogs but I will admit I haven't watched all of them
Have you ever talked about Absolute Maximum Ratings? I've seen more than one question like "How much can I exceed the absolute maximum ratings and get away with it?" I can picture you screaming "Zero!" but some people just don't get the concept.
, I've been involved in a number of forum threads about the PIC18F25K20, which the Amicus Compiler
(aka free version of Proton Basic) requires. It clearly does not have 5v tolerant pins but there are a few people claiming otherwise. In the pin descriptions in the data sheet some of the pins are listed as Schmidt Trigger and others as TTL, which some people claim means 5v tolerant.
When the absolute maximum ratings of Vdd + 0.3 v on any pin are are pointed out, the argument becomes "the maximum rating for Vdd is 4.5v and the pin is rated at Vdd + 0.3 v so that means the pin is rated at 4.8 volts. And everybody knows that 5v regulators always put out less than 5 volts, so therefore....." I'm certain your reaction is the same as mine to logic like that.
And of course when the errors of that argument are pointed out, the reply is "I've been in this business for 20 years and I do this all the time." You may indeed....thanks for the warning - I'll stay away from anything you've designed.
This example is focused on my current head-banging exercise, but I've heard the same nonsense again and again when it comes to absolute maximum ratings. A reinforcement of good design practice might be a good thing.
JonOne of the forum threads