Hello,
The problematic module is Powertip PC2004A B LCD 20x4. It was used in pc-based setup while it was working. I cannot make any tests there.
At the moment, I do not have another module - ordered and waiting for now and trying to do something with this one.
Regarding timing - yes, that is why I do not trying to develop my code (lot of preparation reading, time...and how to be sure that is wrong code and not wrong LCD?) and have found few of them on Internet that many people saying that it works for them. One of those setups/codes that works, I have found on Internet, use mcu I have spare (PIC16F887) and with literary the same LCD (Powertip PC2004A) - I can post a link if it is allowed by Eda's rules. I do not want copy/paste part of it, i.e. code since it is not written by me. In that forum/posts there is one of successful users with Powertip PC2004A confirming that it works for that LCD. That specific user had only problem with the contrast that he resolved.
Then, I have made my own setup on breadboard and I have compiled source and load .hex file to mcu. After reseting mcu ....not working. After that, I was suspicious about that .hex file and made a simulation in simulation software (same setup as on breadboard) and it worked perfectly. I can post simulation here as well.
So, that hardware setup and code works in simulation and to other people in practice - I have concluded that problem is related to hardware of this specific LCD. (Hope that my breadboard wiring is okay).
Reason asking about resistance and capacitance of the pins - if you recall my comment on "flickering" like it has no power to bring enough light to cells and after that , during working period, cannot clear screen and/or write characters on screen - I have thought if it possible that LCD has some current leakage to the GND or it has some huge capacity, from somewhere, that cannot be loaded initially in reasonable time and during writing text on screen it do not discharge fast to refresh cells.... Sorry, if I have gone to far with my thoughts but ...
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