Quote Originally Posted by Ioannis View Post
I guess you have biased the MCLR pin, right?

Ioannis
I don't know the term "bias" in relation to the MCLR pin; but if you mean put a zener upside down so it breaks down over a given voltage, then yes, I'm biasing the pin.

Scroll down here to the paragraph called Zener Transient Suppression.

https://www.electronics-tutorials.ws...ppression.html

I'm going to go one step further with zener diodes. I'm gonna add a 1N5243BTR on MCLR to break down at 13 volts, and a ‎1N5232BTR on VDD to break down at 5.6 volts (specs say 5.5V is "max" - but I figure they're leaving a small margin for safety).

Unless someone has a good reason why I shouldn't...?


Why don't you get rid of the crystal and use the pic internal oscillator ? That should stop your hand capacitance causing problems on the crystal circuit.
I'm not seeing an internal oscillator on the 16F877: LP, XT, HS and RC. If you mean RC, it uses a capacitor as well. Won't that cause the same issues? They also mention other issues, like accuracy/tolerance of the resistor and capacitor, as well as temperature.

This will ultimately run a USB or USART connection as fast as I can.


I've tested the new breadboard using two gold pins from a header as probes (those pins are thick, clean and square) and I'm still getting a lot of "looshish" spots in some areas. The much thinner pins on capacitors, oscillators and some resistors must definitely be messing up my circuit.


Also, I think I have some capacitor/interference issue with my Lab X1 as well (probably not even related with my breadboard issues, just bad timing). Waving my hand over the X1 should not affect operations. It's possible it now has a defect; I bought it when they came out.


I'm looking at using fiberglass breadboards and soldering my components. I've been thinking of making my own Arduino-ish circuits for testing for a very long time. This might be the time to give that a try.


Side note: the tips on my Aoyue 738 soldering station are garbage. Bought some new ones on Amazon and they just don't last. One comment on the listing was "I've had packs of gum that lasted longer"; he wasn't exaggerating.

I bought new soldering paste since mine was 20 years old and had spent winter in unheated garage. I've just received today one of those brass brush balls to clean the tip; hoping that works better than that water sponge (never liked that).

Robert