Cannot get LCD to work
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Cannot get LCD to work
Hi, I'm on build 20181220 on a Nodemcu V3. I try to connect an LCD 2004.
On the I2C scan it finds the lcd on address 0x27.
Now, when I enable the device and write "IP %ip%" on the first line, the display remains blank.
Also, I'm not really sure what interval is for.
Thanks for any hints.
On the I2C scan it finds the lcd on address 0x27.
Now, when I enable the device and write "IP %ip%" on the first line, the display remains blank.
Also, I'm not really sure what interval is for.
Thanks for any hints.
Re: Cannot get LCD to work
Do you connect "VO" pin (contrast)
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Re: Cannot get LCD to work
potmeter adjustment ?
30+ ESP units for production and test. Ranging from control of heating equipment, flow sensing, floor temp sensing, energy calculation, floor thermostat, water usage, to an interactive "fun box" for my grandson. Mainly Wemos D1.
Re: Cannot get LCD to work
Hey thanks for the reply. I connected the four pins GND,VCC,SDA and SCL.
EDIT: The tip with the potmeter helped but the highest contrast is still barely visible.
EDIT: The tip with the potmeter helped but the highest contrast is still barely visible.
Re: Cannot get LCD to work
The text is weak in dark color instead of being bright and white on the blue background.
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Re: Cannot get LCD to work
Display needs 5V.
Use a level-shifter for SDA and SCL.
Use a level-shifter for SDA and SCL.
30+ ESP units for production and test. Ranging from control of heating equipment, flow sensing, floor temp sensing, energy calculation, floor thermostat, water usage, to an interactive "fun box" for my grandson. Mainly Wemos D1.
Re: Cannot get LCD to work
Okay, I will try that, thanks.
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- Normal user
- Posts: 307
- Joined: 06 Nov 2016, 13:45
Re: Cannot get LCD to work
30+ ESP units for production and test. Ranging from control of heating equipment, flow sensing, floor temp sensing, energy calculation, floor thermostat, water usage, to an interactive "fun box" for my grandson. Mainly Wemos D1.
Re: Cannot get LCD to work
As I am a beginner that line didn't ring a bell for me when I read it.
Luckily I have bought plenty of different parts in advance and I found a level shifter.
Now it works like a charm.
Maybe the wiki entry could be dumbed down for beginners like me, that think it's enough to plug&play.
Anyways, thanks a lot for the advice. I'm looking forward to play with that lcd
(for beginners like me: lv is 3.3v, gnd is gnd, lv1 is sda old, lv2 is scl old
then on the other side: hv is 5v source, gnd is correlated gnd, hv1 is sda new, hv2 is scl new)
Luckily I have bought plenty of different parts in advance and I found a level shifter.
Now it works like a charm.
Maybe the wiki entry could be dumbed down for beginners like me, that think it's enough to plug&play.
Anyways, thanks a lot for the advice. I'm looking forward to play with that lcd
(for beginners like me: lv is 3.3v, gnd is gnd, lv1 is sda old, lv2 is scl old
then on the other side: hv is 5v source, gnd is correlated gnd, hv1 is sda new, hv2 is scl new)
Re: Cannot get LCD to work
I like to sugest to author of plug-in for I2C LCD 2004 to extend range of I2C address to 0x4f (http://www.ti.com/lit/ds/symlink/pcf8574.pdf page 13 ).
Thank you
Thank you
Re: Cannot get LCD to work
I added an issue for it, so it will not be forgotten.velja wrote: ↑12 Dec 2019, 09:57 I like to sugest to author of plug-in for I2C LCD 2004 to extend range of I2C address to 0x4f (http://www.ti.com/lit/ds/symlink/pcf8574.pdf page 13 ).
Thank you
See https://github.com/letscontrolit/ESPEasy/issues/2813
Re: Cannot get LCD to work
Hello,
I have connected an ODROID 20x4 LCD from Pollin:
https://www.pollin.de/p/odroid-h2-i2c-2 ... dul-810957
I can see the text on the display, but it is also weak and dark and not white as it should be. If I reconnect the display while ESPeasy is running, I get (of course) random characters, but they are bright white!
So it doesn't seem to be a matter of voltage. The display is specified for 3.3V by Pollin and in the ODROID guide it is also connected to 3.3V.
https://wiki.odroid.com/odroid-h2/appli ... d#tab__h21
So it seems to be a matter of initialization...?
Thanks for your help!
I have connected an ODROID 20x4 LCD from Pollin:
https://www.pollin.de/p/odroid-h2-i2c-2 ... dul-810957
I can see the text on the display, but it is also weak and dark and not white as it should be. If I reconnect the display while ESPeasy is running, I get (of course) random characters, but they are bright white!
So it doesn't seem to be a matter of voltage. The display is specified for 3.3V by Pollin and in the ODROID guide it is also connected to 3.3V.
https://wiki.odroid.com/odroid-h2/appli ... d#tab__h21
So it seems to be a matter of initialization...?
Thanks for your help!
Re: Cannot get LCD to work
I found that the display should have a charge pump to get the needed LCD voltage if VCC is 3.3V.
But this charge pump is not fitted on my display, so it is not for 3.3V use Thanks, Pollin ...
But fitting this charge pump may be an alternative to 5V and I2C level shifters.
https://www.element14.com/community/gro ... cds-to-33v
But this charge pump is not fitted on my display, so it is not for 3.3V use Thanks, Pollin ...
But fitting this charge pump may be an alternative to 5V and I2C level shifters.
https://www.element14.com/community/gro ... cds-to-33v
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