I have a ESP8266 with a 5110 display running U8g2
The display is too dim to read.
when run from a NANO, the same sketch, the display is bold.
Both are run from 3 volt pins, neither uses the back-light.
the contrast statement has no effect and I have read that some of these displays do not have variable contrast. assuming it is a feature in the actual driver chip.
i don’t know the LCD, but is it designed to run from 5V or 3V ?
dave-in-nj:
Both are run from 3 volt pins, neither uses the back-light.
Do you actually mean 3V or are the suply voltages of the ESP8266 and NANO 3.3V ?
What is the measured suply volts to the 5110 when its used with the ESP8266 and the NANO ?
The 5110 display might be getting parasitic 5V power though the data pins, when connected to the Nano, even though the power is connected to 3.3V.
both of my examples are powered be the 3.3v on-board voltage regulator.
and, yes, I am using the NANO pins directly.
from what I have read, the 5110 is designed for 3.3v, and 5v tolerant.
most sites say to use 3.3v.
the contrast statement has no effect and I have read that some of these displays do not have variable contrast. assuming it is a feature in the actual driver chip.
It may be worth looking further into this...
lastchancename:
Quotethe contrast statement has no effect and I have read that some of these displays do not have variable contrast. assuming it is a feature in the actual driver chip.
It may be worth looking further into this...
u8g2 has one contrast option from 0 to 255
changing values in contrast has no effect.
I have come across sites where they mention that contrast may not be accessible due to circuit board design.
thinking I should have started this thread in the displays section.
I have not tried any other display libraries, u8g nor adafruit
dave-in-nj:
both of my examples are powered be the 3.3v on-board voltage regulator.
Maybe so, but what is the answer to the question in #2;
"What is the measured suply volts to the 5110 when its used with the ESP8266 and the NANO ?"
Small differances her could have a significant effect.
srnet:
Maybe so, but what is the answer to the question in #2;"What is the measured suply volts to the 5110 when its used with the ESP8266 and the NANO ?"
Small differances her could have a significant effect.
tossed in A0 on the nano, connected grounds.
3.53 on the ESP
3.54 on the NANO
dave-in-nj:
tossed in A0 on the nano, connected grounds.
3.53 on the ESP
3.54 on the NANO
A0 ?
Your powering it from a logic pin ?
srnet:
A0 ?Your powering it from a logic pin ?
question was asked: what voltages ?
connected a jumper to pin A0 on the nano
connected grounds
read voltage of the two boards
power to each was from USB on different ports
dave-in-nj:
question was asked: what voltages ?
connected a jumper to pin A0 on the nano
connected grounds
read voltage of the two boards
power to each was from USB on different ports
Still not clear where the VCC for the 5110 is comming from, you have said so far;
'tossed in A0 on the nano, connected grounds'.
'connected a jumper to pin A0 on the nano'
Can you provide a circuit diagram ?
Hi,
Do you have a DMM?
What is the voltage supplied to the power pin of the display?
Can you post a picture of your project with the dim display, so we can see your connections.
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
Thanks.. Tom... 
UPDATE :
it was a hardware problem. I found that when I removed the plastic screen protector, the screen was scratched and dirty around the edges. it was a pull from some device. they seller noted that one might have to squeeze the screen to get better contact.