Unable to communicate with LCD2004a via I2C (Nucleo-F103RB)

[Oyose.1]

Hell guys, i'm trying to communicate with LCD2004a with the I2C extender.

i followed this guide https://www.youtube.com/watch?v=7mQppaEJjT4

what i did:

1. I generated project using CUBEMX to Keil uvision
2. configure I2C with those parameters: 100Khz CLK, slave address 0x27( i checked with I2C scanner that is actually the address)
3. added the library i2c-lcd to my project (downladed from the link in the youtube video)
4. change the parameter SLAVE_ADDRESS_LCD in the source code of the library to 0x27
5. connect the SDA to PB7 and SCL to PB6 like the default pinout that CUBEMX offer me

and nothing happened.

is look like the LCD not communicate with my board at all

those modules working well with Arduino so the problem is not with them.

i attached the main function, library and my pinout to this post

[waclawek.jan]

Observe the pins using oscilloscope/logic analyzer.

Debug the code as usually, yes, that includes Cube/HAL, it's open source.

JW