Newhaven 4x40 LCD, issues!

[Christopher4187]

That's the entire code. I rechecked everything and everything looks okay. I bought two LCD's so when I get home I'll try the other one. I don't know what else I can check. I have an old Mikroelectronica board that has pins for parallel LCD's so maybe I'll use that with the standard code (all pins on the same port) to see if it's my hardware or software that's causing the issue.

[Darrel Taylor]

With those configs ... the PIC is running at 48mhz, not 20.
So change the DEFINE OSC 20 to DEFINE OSC 48.

And like Dave mentioned ... add ADCON1 = $0F before the LCD pins/include.

[MOUNTAIN747]

Christopher, I had all my wiring correct and the code looked good but I still had no display. The problem was Vo. The contrast was a critical adjustment. Once I found the sweet spot, just above 0 VDC, all was well.

I've attatched a txt file with the code to test the LCD using E1 & E2, no other hardware needed. R/W can be tied to GND or to an output. Make the necessary VAR pin assinment changes. This code will write to all four lines without using LCDOUT command.

Wayne

Newhaven_4x40_Test Code (1).txt

[Christopher4187]

I've tried everything you guys suggested and still no dice.

I went back to the normal LCDOUT commands where I have everything on PORTB. I've tried my Easypic3 board and the 2X16 LCD that came with it, along with 3 other LCD displays I had laying around. I get one line of solid characters, which of course is adjustable with the contrast POT on the board. The LED blinks as intended but nothing on the LCD screen. Do I need to pull up or down any other lines? Is there anything else I can check?

I'm thinking it might be my files or programmer, but my other programs program just fine. I even reinstalled the PBP file that I modified last night for DT's program but I get the same results. Anything else I can check?

[Christopher4187]

Nevermind, I'm an idiot. I got the Easypic3 board working and now I'll move onto trying to make the NewHaven LCD screen work.

[Christopher4187]

I can confirm all LCD's work on the Easypic board but I can't get any to work on the demo board. Can someone check my modified pbppic18 file to see if it's correct? I can't tell if I have a hardware issue or a software issue.

> DT > The modifications were correct.
Copyrighted file removed.

[Christopher4187]

Problem solved......kinda.

I can get DT's program working on my Easypic board but not on my demo board so my issue is definitely hardware. I need a magnifying glass........

Thanks to everyone who helped, I learned a lot!

[Christopher4187]

The issue ended up being a capacitor on the demo board. I'm assuming that the rise time for the data lines wasn't quick enough. The other thing I've learned is, this LCD does not have contrast control and therefore Vo does not exist on this screen. Seems strange but that's why pin 3 is listed as N/C.

Darrel, this program is awesome. You deserve a raise!

[MOUNTAIN747]

Christopher, pin 3 is DB5, pin 16 is NC. If you have a 20k pot center taped to Vo you should have contrast. I can vary the contrast on my 4x40 over about a turn and a half of the pot. It goes from almost no visible characters to bright characters. Look over your Vo hardware once more.

Wayne

[Christopher4187]

Christopher, pin 3 is DB5, pin 16 is NC. If you have a 20k pot center taped to Vo you should have contrast. I can vary the contrast on my 4x40 over about a turn and a half of the pot. It goes from almost no visible characters to bright characters. Look over your Vo hardware once more.

Wayne

You have an LCD screen. I have an OLED screen ( I know I put LCD above but it was a mistake). Pin 3 for me is no connection. Putting a POT on pin 3 does nothing. Again, this board does not have a Vo pin.

I suppose you could adjust the contrast by lowering the input voltage if it's really necessary.