MicroPython Forum (Archive)

Hey everyone!

I set up an ssd1306 on my pyboard and everything (initializing, commands) works fine, except one thing:
if I send data into the GDDRAM, it just appers for a moment and than disappears. So I can see the text for example, but if
I want it to stay there, I have to refresh my function fastly. The strangest thing is that sometimes it works well. it is total random.

I use the builtin FRAMEBUF module, and I2C module from the MACHINE libary.

Are you using the official driver?

No, It is my own, but mainly the same. Anyway the i2c.write() and i2c.stop() method doesnt work with the pyboard.
I'm using i2c.writeto(). What I realized as a real difference: 'addr << 1'.
I'm going to try it and feedback!

ENODEV error by the modified address.. It is fixed mechanically on the PCB by the producer company!
Just so tiny - hard to realize. So if I remove the solder it must work well, doesn't it? Actually the display is not mine but my friend asks me to solve his trouble. I use a ssd1327 with SPI and it works so as it is writtened.

Unrelated but worth mentioning. Some SSD1306 modules are sold as SPI interface but are actually I2C and vice versa. Look for a CS pin to be sure it’s SPI. Four pin modules are almost certainly I2C.

It is solved.

First: using 0x3D as address is not necessary.

Second: I had put the D/C bitpattern into the buffer, when write data, and increased the bytearray size.
It was look like: bytearray(1 + (width * height)) >>or pages instead of height<<
buffer[0] = 0x40 (reserved)
Now it has just the right size, but the first element is the same D/C selector yet.

Actually it is a really cheap copy: there is no brand name, false serial addresses writtened on PCB, but at least it has only four pins.