Arduino for STM32

Hi GonzoG,
many thanks for your reply,
I totally forgot that!
Now it works!
many thanks!

1. Did you connect both boards to a common ground ??
2. did you use pull-up resistors on IIC lines ??

No, for this first test, I am just working with the master board, I let the pins free, without wires, without connection.
So, if my understanding is correct, in these conditions, the following line ...

Hi,
unfortunately, I am not able to communicate between 2 STM32F411 blue pill boards with I2C.
From, the master, I removed all the extra code, and I just keep the code for communication.
I've unplugged all wires between the two boards. Master is not connected on the SDA (PB4) and SCL (PA8) lines ...

Could you try to change this line:

https://github.com/stm32duino/Arduino_C ... twi.c#L718

Code: Select all

- handle->Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;
+ handle->Init.NoStretchMode = I2C_NOSTRETCH_ENABLE;




It works!!!!!

This is the issue
now, blackpill is detected by the jetson ...

yes clocks are set to 400Khz on both sides

And here is the signal, having Jetson Nano, servo controller but without the black pill board

https://ibb.co/2nTnXht

Forgot what I said...
SCL pin was not LOW
I forgot to reset the board after the blocking issue and the signal remained LOW.
What we can say is after resetting the board:
the signal is effectively HIGH
but as the Jetson Nano is checking the Blackpill the SCL signal becomes LOW and stay LOW ...

With the following errors I am sure we can avoid Jetson nano issues:

I removed the Jetson Nano from the I2C lines.

I had these two experiences:

1/ Blackpill configured as slave:
put the logic analyser on pins PB7 and PB6 (SDA and SCL)
SDA HIGH
SCL LOW

2/ Blackpill configured as slave with pullup ...

Jetson Nano is 3.3v.
I just put a logic analyser and here is what I've found:

- Having pull-up resistors on both SDA and SCL lines.
- Having a servo controller on the I2C lines

1/ Without blackpill
data recorded by the logic analyser shows SDA and SCL at high stage.
This is aligned with the I2C ...

Seriously, I've told you that I used a shield with 2 I2C devices... so... this is the @ of those 2 devices...


Ok.


The weact black pill have a 25MHz xtal for HSE, it seems the one you point also. Anyway you should check this.
You should try the I2C scanner with your board.


Checked. It is a ...