I have a small project with AT89S52 and LCD 16x2. I build circuit and simulation in Proteus. It works normally. But when I build PCB, LCD can't display the value. I just adjusted rheostat to change LCD's contrast and it worked. Can you told me the mistake that I have?
closed as unclear what you're asking by pipe, Voltage Spike, Elliot Alderson, Edgar Brown, Dwayne Reid Jan 11 at 19:17
Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.
I don't see much in the way of decoupling on that board, which simulators generally don't care about, but real implementations do....
Is the micro even running? You could write a simple program to toggle a pin and stick a scope probe on it to see if the processor is working? It is generally worth hanging a few LEDs on some spare pins because it makes early bring up very much easier.
Those LCD modules are often quite picky about timing, especially during the setup phase, read the datasheet carefully and make sure your software meets the described timing.
Simulators are somewhat useful for telling you that something will NOT work, but they have very limited value in telling you something will unless you know exactly what you are doing to start with.