16x2 JHD162A Top Row Blocks. Crap hardware?

Hey everyone,

I just bought a new 16x2 LCD as my former one stopped working and would only display blocks on the top row. The thing is that I didn't even get to use my new one once before it started doing the exact same thing. I tried with two different programs, one with a PIC16F877A and one with a PIC16F628A, both in 4 bit. Neither of them work in either of the displays.

All wiring is correct. Checked the wires for continuity as well as the solder joints and the pads. Not a contrast problem. I also tested the 16F628A with an LED chaser program with no problem, so it's not the MCU.

I didn't find it too hard to believe that the first one had just failed but the second one I bought, I didn't even get to use once!

Is this a hardware problem? Are these known to be faked just like bad transistors? Really annoyed by this as it seems I may have just wasted my money on this replacement. How frustrating!

Attached is a picture of what the display looks like as well as the sample program I'm using to test it.

What about the pin no.3 of the LCD ? as it not visible(pin no.3) or if you have not attched any thing then attach a POT(variable resistor) to the pin and therefore the CONTRAST of the LCD changes

If you still face any problem let me know ?

Hi,

There I put a resistor, in the picture I beliee it is a 270 ohm resistor. I experimented with the value, both higher and lower. The contrast does change but the blocks don't go away.

You have specified the oscilator frequency 4Mhz in project and in proteus. But your real h/w working from XT crystal oscillator that realy not exist at all. Sure, it will not work.

Hi,

The oscillator is present in the circuit along with the capacitors. Also tried this with two differen't circuits, both had their respective oscillators included.

What oscillator? 4Mhz XT? Or HS?
MCLR pin still requre an pull-up resistor. Turn off MCLR pin in project settings.

The oscillator is an external 4Mhz oscillator with two decoupling caps to ground, if this is what you mean. I tried turning off MCLR with no difference either.

I find it very strange I could have two LCDs go bad but I can't explain what's going on here! Also checked to see if maybe my power supply was giving out ripple but it's fine and stays a steady 5V:

Try with internal RC oscillator on 1Mhz. Make some port-check routins like:
trisb=0;
while(1)
{
portb=0;
delay_ms(1000);
portb=0xff;
delay_ms(1000);
}
and check that portb changing their state once per second.

It seems to be some initialization problem with 8 bit or 4 bit mode or delays after power up in sending this.
https://www.lcd-module.de/eng/pdf/zubehoer/ks0066.pdf

perhaps

Mimuwhen : YOu put your initialization FUnctions / related things once plz

the problem must be with improper delays .................