unable to get 1602 LCD working with teensy LC via I2C

[Phil Sznyck]

Hello World. It could be so easy, but its not. I've downloaded 6 different libraries, and read lots of stuff here and on other places - couldn't find a solution:
I want to implement a LCD screen to my project. Bought a cheap 1602 with already soldered i2c board on it. soldered it to my teensy LC, with the resistors from the 3,3v out to each sda (on pin 18) and scl (on pin 19). Not an single example from any library worked. The back light turns on, but basically thats it. Tried changing the power pin to the one giving 5v. nothing changes. Anyone some good advice please? I want to be able to write the infos that where originally given by 4 leds with words using a LCD. the theory sounds so good...
I attached a little schematic of my wiring, maybe here lies the problem, in the way I've connected the resistors?
using the "scanner" example in the "wire" library I've got this output from the serial monitor:
Device found at address 0x27 (MCP23017,MCP23008,PCF8574,LCD16x2,DigoleDisplay)
maybe this helps on finding a way to get it working!

 

[MichaelMeissner]

Back when I was still using 16x2 displays, I had a few that needed 5v power plus 5v SCL/SDA. This meant I needed to do a voltage level shifter from 3.3v on the Teensy side to 5v on the display side. There are chips that do the voltage conversion, but another method might be to go with a different display that works with 3.3v.

BTW, given that the scanner finds the display at address 0x27, it means the resistors are properly set.

Another possibility is the display just doesn't work. Maybe some wire broke or something.

 

[XFer]

If your display has a contrast trim, turn it to the maximum.
I have a 2004, a bit different, but without turning the trim to the maximum I was in the same situation (backlight ok, communication ok, but blank screen).