24.4.4.3.2 I3C Controller Request

If the received IBI ID matches the Dynamic Address of any one of the valid entries in the DAT and the received RnW bit is 0, the response for the received MR is based on the programmed value of the MRREJ field of the device address table (DAT).

The Controller mode allows the application to either set the I3CxDEVADDRTABnLOC1[MRREJ] to 0 or 1 individually to accept or reject the MR request, respectively. The application is expected to always set I3CxDEVADDRTABnLOC1[MRREJ] to 1. This requirement allows the Controller to reject any MR request if received unexpectedly from a malfunctioning Target device.

If the I3CxDEVADDRTABnLOC1[MRREJ] is set to 1, the Controller responds to the MR request with NACK, followed by issuing a directed DISEC CCC command (DISMR bit set) with the RESTART condition to the MR-initiated Target. The Controller sets the ‘IBI_STS’ field in IBI Queue Data Structure as NACK to indicate to the application that the Controller has rejected the received MR request. The application can optionally set the MR Reject Notify Control (I3CxIBIQNOTIFY) to get an IBI Status for a rejected MR request. Otherwise, the Controller moderates the IBI Status generation for rejected MR requests.

If the I3CxDEVADDRTABnLOC1[MRREJ] is set to 0, then the Controller responds to the MR request with ACK and sets the ‘IBI_STS’ field in IBI Queue Data Structure to ACK, which indicates to the application that the Controller has ACK’d the received MR request.

Based on the IBI status for the MR request, the application must follow the Controller ownership handover procedure.

Figure 24-10. Programming Flow to Switch from Controller to Target Mode
Note: If the received IBI ID (MR) does not match any of the dynamic address entries of the DAT table, the Controller sends a NACK response and generates IBI status to the application. The Controller does not send any disable event command and expects the application to take necessary action if the unknown device repeatedly interrupts. In this case, the generation of IBI status is independent of the MR Reject Notify Control settings.