Sending data using I2C on Simulink

I'm using Nucleo-G474RE to send a bit stream over Simulink, instead of receiving 24 bits on the oscilloscope i can read only 8 bits, which are supposed to be the 8 bits in the middle that have the address of the peripheral and the status of the I2C block gives me 516 which is not on the documentation from matlab.

Answer 1

[Aditya]

Hi Abdurahman,

Only 8 bits seen: Your Simulink I2C Write block is likely configured to send just 1 byte (the address), not all 24 bits (3 bytes).Fix: Set the "Data size" in the block to 3, and input a 3-byte array.Status 516: This is not a standard Simulink code; it may mean "bus busy" or an error from the STM32 HAL library.You can check the following to resolve the issue:

1. Check your I2C Write block settings: send 3 bytes, not 1.
2. Make sure your I2C wiring and pull-ups are correct.
3. Adjust your oscilloscope to capture the full transmission.
4. Try updating your STM32 support package.

[Abdulrahman]

Hi Aditya,

Thank you for your reply! It worked after trying out a few different solutions. I updated the the STM32 support package, and used a different pull up resistor, 56k Ohm. It looks like 516 means that nack has been received