SSD1306 display doesn't work

[undefinedCat]

I have a 128x32 display, and this is what I typed into the REPL:

>>> from machine import Pin, I2C
>>> import ssd1306
>>> i2c = I2C(scl=Pin(5), sda=Pin(4), freq=100000)
>>> screen = ssd1306.SSD1306_I2C(128, 32, i2c)

And after that it shows this error:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "ssd1306.py", line 118, in __init__
  File "ssd1306.py", line 37, in __init__
  File "ssd1306.py", line 74, in init_display
  File "ssd1306.py", line 123, in write_cmd

What's the solution to this problem?

[robert-hh]

It looks like a basic communication problem. Call print(i2c.scan()) after instantiating i2c to see, if the display is detected and at which address.

[NeuralShan]

I have been facing the same issue, and tried calling the .scan() function, but it returned a blank array [ ].

[peterhinch]

If .scan() returns [] there is a hardware problem. Incorrect connections, lack of pullup resistors or a device problem.

[karfas]

What's the solution to this problem?

This is hard to tell without seeing the error message you got.

However, I would assume you have some kind of connection problem.
Does i2c.scan() find the display at the correct address ?
Do you have proper pull-up resistors in place ?

[shariltumin]

I have an i2c ssd1306 oled display and can confirm that I have the same problem.

The display works on esp32, esp32s2 but not esp8266.

I have made a copy of "ssd1306.py" to "oled.py" so that I can put in some debugging messages.

The ssd1306 module reports ENODEV during init:

MicroPython v1.22.0-preview.246.g4365edb81.dirty on 2024-01-15; WEMOS D1 MINI 4MB with ESP8266
>>> 
>>> from machine import Pin, SoftI2C
>>> i2c = SoftI2C(sda=Pin(4), scl=Pin(5))
>>> i2c.scan()
[60]
>>> import oled
>>> display = oled.SSD1306_I2C(128, 64, i2c)
Write CMD: 60 bytearray(b'\x80\xae')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "oled.py", line 119, in __init__
  File "oled.py", line 38, in __init__
  File "oled.py", line 75, in init_display
  File "oled.py", line 125, in write_cmd
OSError: [Errno 19] ENODEV
>>> hex(60)
'0x3c'
>>> i2c.scan()
[60]

[shariltumin]

Sorry, please disregard my post above. It seems that the board I did the test on was defective. Doing the test on another esp8266 boards worked fine.

[zuofeng64]

screen = ssd1306.SSD1306_I2C(128, 32, i2c)
这句是否错了，
screen = ssd1306.SSD1306_I2C(128, 64, i2c)