PiicoDev could not communicate with module at address 0x3C, check wiring

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1

Hi looking to get some help with the error

PiicoDev could not communicate with module at address 0x3C, check wiring

I’m trying to wire in a PiicDev OLED Module SSD1306, but the cable connector on the end of Piico Dev adapter snapped off :frowning: , so I’m wiring directly to pin on the PiicDev expander board. I have downloaded code in the video, I have the break-out cable with the pins pulled into the OLED module. I have red lead in pin 5 3VC, black in pin 3 GND, and blue in pin 8 SCL and yellow in pin 9 SCL. The OLED ASW set to Off.

The green led on the back lights up when I run the code

cheer
David

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2

Hi David,

Would it be possible to attach a photo of everything connected?

That setup should work, I’d check pins 8 and 9 relate to the GPIO numbers rather than the physical pins.

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3

cheers thanks Liam,

20230423_145903
20230423_1459031889×1417 299 KB

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4

I re read, the first post, I got the pin’s info wrong slaps heads

This is what I have now …

Blue in pin marked SCL - 9
Yellow in pin marked SDA 8

The green led on the OLED module turns on, but the same “PiicoDev could not communicate with module at address 0x3C, check wiring” message

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20230423_15074311920×1440 333 KB

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5

Hi David,

Sorry, Blue (SDA) is correct in pin 8 and Yellow (SCL) is correct in 9.

Everything should be working as intended with this setup.

If you run the following in the REPL whats the response?

from machine import I2C
i2c = I2C(0)
i2c.scan()
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6

OK, done

Blue in SDA Pin 8
Yellow in SCL Pin 9
Bellow is the result of scan

from machine import I2C
i2c = I2C(0)
i2c.scan()
[60]

7

Ok ran the sample code. No green LED, No errors. No display.

If I hit Stop on Thonny if gives a Unable to coonect on com port 4. I have to reset the Ras Pi

8

Hi David,

If you’re getting back 60 in your scan, that’s decimal for 0x3C, so your connections are right, I think it could possibly be something wrong with your code, could you double click on the main.py file in Thonny and paste its contents in here? Just want to rule out errors there.

Keen to get to the bottom of this one!

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9

Cheers, thanks to all who are helping on this. It gets stranger. I replugged it all in again and ran the code again (this is the demo code from the OLED site) and it started to run the demo. :face_with_spiral_eyes:

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20230424_1504491573×2097 105 KB

The only thing I can think of is the plug wasn’t seated all the way, this feels right up there with turning it “off and on again”. I will keep on with the demo code, but at the moment it seems to work. Thanks again to the clever people in the forum.

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