I have two LCD 1602 with I2C adapters. These come from two different suppliers and where purchased in different years. I think this is important as I suspect a chip version / library issue.
I've built a quick clock with DHT11, RTC1302 and a rotary encoder.
When using one LCD everything is working fine. When using the second LCD it looks like everything is fine except for certain positions on the screen (mostly every 4th position).
It will display TEMP and sometime it will display TEM or TEM(strange character). After a delay I display HUMID (followed by the value) but sometime it will only write HUM(strange character)D. I use the LCD.clear(); when displaying new information and as mentioned, one LCD is working perfectly.
So one LCD is working fine, the other has strange behaviors. My wishful thinking wants to say that both LCDs are good except one is using a different chipset and the library is not 100% compatible.
Working LCD : PCF8574T K75111 (I2C adapter purchased seperately from LCD and soldered by me)
Strange behavior LCD : PCF8574T AZ2629 (KEYESTUDIO kit)
I've tried different LquidCrystal_I2C libraries (I've erased the old libraries before installing newer versions).
I displayed regular text without the BIG FONTS, I still get the same issues.
Anyone ever see this kind of behavior ?