Im using stm32 bluepill im trying to use OLED 128x32 i have tried libraries but nothing is working,same OLED worked with Adruino Mega. If anyone knows what might be the issue please let me know[SOLVED]

[KnarfB]

You probably have an error.

hth

KnarfB

[Qsdxkh]

I've tried many many libraries but no luck. The screen remains blank. No response.

But the same screen works with arduino. So i know connections are fine, only problem with coding.

Here are the libraries that I've tried

1. https://github.com/vookimedlo/stm32-ssd1306
2. https://github.com/GolinskiyKonstantin/STM32_Lib_OLED_SSD1306_I2C_SPI
3. https://www.youtube.com/watch?v=ruDyTsmVls4
4. https://www.youtube.com/watch?v=Mt6U30Yxrr8

I've also tried changing the address from 0x78 to 0x77 and 0x3C but no luck.

I do not get error in any of them but the screen remains blank.

[Mike_ST]

Hello,

Do you have pull-up resistors on the I²C lines ?

[Qsdxkh]

No i have connected them directly, i will try using pull up resistor and let you know

[Qsdxkh]

Hello @Mike_ST​  i tried with pull-up resistors 4.7k but still no response from oled display.

It works fine in all the videos on youtube even without pull-up resistor.

Can you suggest any other trouble shoot?

[Mike_ST]

>It works fine in all the videos on youtube even without pull-up resistor.

In theory, I²C lines needs pull-up resistors, whatever the videos are showing.

They might have used internal pull-up resistors, but in some cases this is not enough.

> Can you suggest any other trouble shoot?

Check the I²C signal with a scope, and check that it is running at 100KHz.

[Tesla DeLorean]

>>I've also tried changing the address from 0x78 to 0x77 and 0x3C but no luck.

What address is working on the Arduino?

Typically the ST side wants (addr << 1), where as Arduino wants (addr)

Does the STM32 HAL side I2C code indicate the address was acknowledged, or not?

Any error status reported via the HAL commands?

Show a wiring diagram of the pins you're using, and what connects to what.

Make sure you're properly initializing the pins.

[Mshar.2 · Accepted solution]

Hello, I had the same problem. While debugging i found that device was not getting initialized because I2C status flag was stuck on "BUSY" and i couldn't found why.

Temporary solution is to use STM32 Cube IDE instead of Cube MX. Everything worked fine for me in CubeIDE.

Also, if i copy-paste i2c.c and i2c.h file from Cube IDE folder to Cube MX folder, then Cube MX also works properly