Using i2C SSD1306

[jimmie]

I am learning how to use the new board. Debugging is a lot easier using an LCD so I am trying to use the attached code with an SSD1306 but I am getting the error below. I would appreciate finding out how to fix this or if there is a simple program showing how to use an I2C LCD that would be also great.

Thanks in advance.

Running c:\Users\ttc\Desktop\Pycom Code\main.py

>>>
>>>
♦Traceback (most recent call last):
  File "<stdin>", line 11, in <module>
  File "/flash/lib/ssd1306.py", line 117, in __init__
  File "/flash/lib/ssd1306.py", line 37, in __init__
  File "/flash/lib/ssd1306.py", line 62, in init_display
  File "/flash/lib/ssd1306.py", line 122, in write_cmd
TypeError: argument has wrong type
♦>
Pycom MicroPython 1.18.1.r1 [v1.8.6-849-b0520f1] on 2018-08-29; WiPy with ESP32
Type "help()" for more information.
>>>
>>>

0_1539808713383_main.py

[robert-hh]

@jimmie looks like line 9 should start with:
i2c = I2C(0, ........
And then in the next line i2c instead of I2C has to be used.

[jimmie]

@robert-hh

Thank you @robert-hh .

changed to the code below and it now works.

i2c = I2C(0, I2C.MASTER, baudrate=100000, pins=("P9","P10"))
oled = ssd1306.SSD1306_I2C(128, 32, i2c)

[brossingo]

@jimmie hey, did you manage to make it work? Because when I launch a quite similar piece of code to display things on screen, I got the following mistake :

Traceback (most recent call last):
File "<stdin>", line 133, in <module>
File "<stdin>", line 112, in init
File "<stdin>", line 40, in init
File "<stdin>", line 67, in init_display
File "<stdin>", line 92, in show
File "<stdin>", line 122, in write_data
AttributeError: 'I2C' object has no attribute 'start'

I use the ssd1306.py as described on this link : https://github.com/pycom/pycom-micropython-sigfox/blob/master/drivers/display/ssd1306.py.

[robert-hh]

@brossingo Change the method write_data() in class class SSD1306_I2C(SSD1306) to:

    def hw_write_data(self, buf):
        self.i2c.writeto(self.addr, b'\x40'+buf)

The code in that lib is for the micropython.org branch and was never ported.

[throwaway]

@brossingo FWIW, I managed to get such a display running with the development release firmware (version 1.20rc4) in combination with the write_data() change that robert-hh mentioned. This newer release is required in order to be able to make use the framebuf class.

Here's a post with my notes: https://forum.pycom.io/post/24819