I'm pretty new to I2C but I have an I2C LCD display that I want to use for projects. I downloaded an I2C scanner from here and it found 4 addresses. Here is a screenshot of the serial monitor.
Here is how I wired it (Green is SDA, Blue is SCL).
How is this possible?
UPDATE: I connected it to two potentiometers as resistors (main reason being I lost mine, will work on getting new ones) and I'm still getting the same results. Display does turn on though which is good.
Looks like a hardware problem. Perhaps missing pullups or too long wires.
I updated my post with how I wired it. The SCL and SDA cables are plugged directly into the analog inputs of the arduino, power and gnd is connected to the power line on the breadboard
Which exact Arduino? Uno R4 has known bugs with the I2C bus, causing phantom addresses found.
I see. It's the Uno R4 WiFi.
You have no pull up resistors on your I2C lines. As described by @DrDiettrich in post 2. You seem to be ignoring this.
Also does the LCD display have address lines that you are just letting float?
I wasn't intentionally ignoring this, just wanted to get my wiring uploaded first.
How would I connect the pull up resistors to the display?
Pull-up reistors just connect from the SDA & SCL lines to the +5V.
It is entirely possible for a device to have more than 1 I2C Address - it could use different addresses for different functions; eg, here's an example of a defvice which has two addresses:
However, that doesn't seem particularly likely in this case.
EDIT: or maybe it is - see post #10...
Try looking at the tracker for compatible libraries:-
that is very probably a display (0x3E) with an additional "RGB" LED background controller (0x03, 0x60), that IC might be a PCA9633.
If you would give a link to the datasheet of your display some might tell for sure.
I just read
So I suggest you try to use the the two SDL and SCA connections on the
upper row on your picture.
Seems that the Uno R4 WiFi differs from the normal UNO
It is, indeed, a very different beast!
Sure - I knew that, but according to the problem I mentioned, some of the pinconnections differs. Thats why I pointed to that message.
It's a 1602 LCD made by DFRobot
Just noticed on the back that the chip says 9633. Thank you for pointing this out.
I got the light to turn on using this library but the LCD i2c library isn't cooperating with it.
This is what I was doing originally but was getting the same result. I can try again with the pullup resistors to see if that changes anything.
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