I need your help, folks. I bought a lot of tech garbage. Some LCD from Nokia 1100. The thing is that I wired one of them to an Arduino Uno, without resistors:
3.3 volts out from Arduino to a breadboard, and the LED+, VDD and VDDI pads directly. Of course, also the GROUND pad.
SCLK, SDA, CS and RES pads to corresponding Arduino's pins.
Please post links to the actual displays that you have bought. e.g. Ebay sale pages.
We need to identify which boards you are using from photos of the pcb.
If they are bare panels we need to see the flexi-ribbon cable and any ZIF or soldered connections.
Not a lot of info about the displays. Nokia 1100 or Nokia 1108B (I guess the last one it's a latinoamerican version). No text on the flex or anything like that.
You don't need the backlight (except at night)
I guess that the ribbon might be in the same order as the header pins.
But you need to find the datasheet for your bare panels.
I've got the pinout of the LCD. Since it works for 8 pads LCD, my guess is that also works for 9 pads LCD. Since the IC driver is the same en both (PCF8814), and I get the backlight on with 3.3 volts and GROUND on the same pads for both models.
The only difference is that in the 9 pads version, one pads is unused.
The firt image uploaded in this post (with the legible characters) is from an 8 pads LCD. With the 9 pads I get only backlight. No letters. Also, already tried a custom contrast configuration from the PCF8814 librarie. Nothing.
That's why I'm looking for a way to check if the LCD is damaged in any kind.
Yes, it is quite possible that you just have an UNUSED pin.
But I would look for any identification marks on the panel.
Is it really a 65x96 panel with PCF8814 ? Have you read the ID cmds=0xDA, 0xDB, 0xDC ?
Your "unused" pin might be the SDO pin i.e. how you read data.
The Nokia 5110 panels are 48x84 with a PCD8544 controller.
Quite honestly, I would buy a known COG panel / module. And start again.