How config I3C Target to send NACK

[RFerr.3]

Hi, I would like to know how to disable address acknowledgment in I3C when operating as a target (with an already assigned address) to temporarily hold communication, similar to the OA1EN bit in I2C.

Thanks,

[sjwalker]

In I3C, the NACK response is controlled using the NACK mechanism, which is different from I2C’s OA1EN bit. When you're operating as a target, you can programmatically configure the target to send a NACK under specific conditions. However, there’s no direct equivalent to the I2C OA1EN bit in I3C. Instead, the way to manage this is by controlling the Master-Slave interaction using I3C-specific features like dynamic address assignment and pending transactions.

a general approach is:

Use I3C Command Protocol: The I3C protocol allows the target device to communicate its state to the master. If you want to "hold" the communication or reject a transaction, you could trigger the target to send a NACK on a certain command by not responding to the master’s request or by sending the NACK on specific conditions.

Disable ACK/NACK Configuration: You should check the control register settings for the I3C target device, which may allow you to disable automatic ACK/NACK or modify how the device interacts with the bus when it detects a master’s request.

Master-Slave Control in STM32: For STM32 specifically, this would involve configuring the I3C peripheral's registers. You can consult the STM32 I3C driver documentation and examples to see how to manipulate the I3C target’s behavior. The NACK behavior can be invoked by setting appropriate flags in the device's I3C control registers.

If this is part of a more advanced I3C communication scenario, such as with pending transactions or advanced clock stretching features, the STMicroelectronics reference manual or I3C protocol specification would provide detailed guidance on manipulating the target's response based on your needs.

share your experience

[RFerr.3]

Looks like an AI-generated response :eyes:

[RFerr.3]

Hey @Saket_Om, any hints on this?