I3C – Can’t get bidirectional Communication working

[BioKeks]

Hi guys,
I'm coming from Arduino and recently started working on a project where I need a protocol that supports bidirectional communication between MCUs and Hot-Join.
I decided to give I3C with the STM32H5 a shot and got myself some Nucleo-H503RB boards.

Based on the example projects from ST on GitHub:
https://github.com/STMicroelectronics/STM32CubeH5/tree/main/Projects/NUCLEO-H503RB
I got these things working:

• Target sends a Hot-Join
• Controller detects it and assigns a dynamic address
• IBI from the target is received on the controller

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What doesn’t work

I can’t get regular data communication working.

For example, I want the controller to send a string on a button input like "ping" to the target, and the target should respond with "pong".

From my understanding, communication in I3C works something like this:

Target to Controller:

1. Target sends IBI
2. Controller receives IBI and starts listening using HAL_I3C_Ctrl_Receive_IT()
3. Target sends data using HAL_I3C_Tgt_Transmit_IT()
4. Controller receives data in HAL_I3C_CtrlRxCpltCallback()

Controller to Target:

1. Target actively checks if the controller wants to send data using HAL_I3C_Tgt_Receive_IT()
2. Controller sends data using HAL_I3C_Ctrl_Transmit_IT()
3. Target receives data in HAL_I3C_TgtRxCpltCallback()

I just want to get a basic setup running where the target sends "ping" and the controller replies with "pong", and vice versa.

Any help or a minimal working example for STM32 HAL I3C communication would be really appreciated.

[Saket_Om]

Hello @BioKeks 

Please refer to the examples below: 

STM32CubeH5/Projects/NUCLEO-H533RE/Examples/I3C at main · STMicroelectronics/STM32CubeH5 · GitHub