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Cannot get I2C LCD to work
#1
Hi All,

I can't seem to get the LCD to work.  It works fine outside of SIP, when just using LCD python test code.  But inside SIP the LED Backlight blinks twice very quickly and there is no info on the screen.

Does anyone have any thoughts on what I might be doing wrong?

P.S. I see some notes in the plugin about using pylcd2.py, but that is not in the SIP folders.

Thanks for any help.
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#2
Depending on the type of adapter (backpack) you are using there may be a problem due to the fact that the Pi's output is only 3.3V and most LCDs require 5V. A level shifter may help but there could be other causes.

I will be doing some testing of the plugin and will let you know if I find any other problem.

I am waiting for a level shifter that I have ordered.

Dan
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#3
(2018 Jan 18, 04:35 PM)dan Wrote: Depending on the type of adapter (backpack) you are using there may be a problem due to the fact that the Pi's output is only 3.3V and most LCDs require 5V. A level shifter may help but there could be other causes.

I will be doing some testing of the plugin and will let you know if I find any other problem.

I am waiting for a level shifter that I have ordered.

Dan

Would the fact that it works great OUTSIDE of SIP make any change to your thoughts? I found instructions on setting it up and testing with Python code from YouTube. everything works great and the LCD displays everything the code expects it to.
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#4
Another item of note: When I go into the LCD Plugin, Where it says STATUS, the box says "Off". Should it be saying "on"?
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#5
Update: Dan has been wonderful in working with me to solve this issue. As of about Feb 10, 2018 he reworked the lcd_adj.py file and now the LCD works perfectly! If you are having trouble, please be sure to uninstall and then reinstall lcd_adj.
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