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My wiringWhen I try to scan the i2c address it stays stuck on "i2c Address Scanner" which is the first line of the code. My screen is connected with VCC-5V, GND-GND, SCL- 4.7K resistor->A5, SDA- 4.7K resistor->A4. Nothing displays on screen, and I even tried without the resistors. I also tried with some 10K resistors and same result.

Here in the picture you can see how I connected the screen to the nano. SDA-A4, SCL-A5, VCC-5V, GND-GND.

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    Did you put the resistors in line? Or as pull-ups? Show how you wired that. It sounds like you did it wrong.
    – Delta_G
    Sep 26, 2020 at 16:30
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    Take A look in the picture I hope it helps, I'm a noob
    – peterk
    Sep 26, 2020 at 18:52
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    A 4 kOhm resistor in series is too big. Such resistors are normally used as pullup resistors, so connection from SDA/SCL to Vcc. Resistors in series are in I2C only used to limit current, when having different voltage levels (lower values must be used). Also your solding seems not clean enough. You have tons of burned flux there and the solder points look like they might not give you good contact.
    – chrisl
    Sep 26, 2020 at 19:03
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    that is a really horrible soldering job ... i would not bother to do any troubleshooting until the board is cleaned up and the soldering is properly done
    – jsotola
    Sep 26, 2020 at 20:05
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    Delta_G Could you please show me in a schematic what you mean?
    – peterk
    Sep 27, 2020 at 0:04

1 Answer 1

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From what I am reading it is not properly connected. You are getting what I would expect. ACL of the device goes directly to A5 and a pull up resistor to +5. Same thing with SCL, connected directly, both need pull ups. You did not state what it is connected to. If there is nothing connected you will get nothing. Also the old wire library did not support timeout so you could hang indefinitely.

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  • As I said, I have two 4.7K ohm resistors, one with sda and one with scl. Both are connected with resistors(none directly connected).
    – peterk
    Sep 26, 2020 at 17:37
  • As Delta_G asked, how did you connect the resistors? They should not be in line with the SCL and SDA signals. Could you show a (simple) schematic of how you built it?
    – StarCat
    Sep 26, 2020 at 18:22
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    Ok I just added a picture of how I wired everything hope it helps!
    – peterk
    Sep 26, 2020 at 18:52
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    As stated earlier the resistors need to be pull ups, not in series as your photo shows. Also you need to clean up the solder splatter and flux, that could also cause shorts. Isopropyl alcohol 90% works great. I would suggest you get a temperature controlled soldering iron between 40 and 50 watts max,
    – Gil
    Sep 27, 2020 at 20:51

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