Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 7/19/2024
Public

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5.8.6.5.6.1. MR Response Control

  1. In the secondary master configuration, the controller handles the MR response to the targeted slave through a 32-bit vector control register (IBI_MR_REQ_REJECT). This register is used to control the response individually for each I3C master-capable slave devices. Each bit field of the control register is mapped to a unique 7-bit slave device address through the modular arithmetic operation as shown in the following figure:

    The sum of the lower 5 bits and the upper 2 bits of the Master Request ID (dynamic address of the requesting slave) is wrap-around upon reaching the value 32 (module 32) to uniquely map the bit position of the 32-bit control register.

  2. In the master-only configuration, the controller handles the MR response to the targeted slave through the MR_REJECT control of the corresponding DAT entry.

If the MR response control is set to 1, then 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 slave. The controller sets the IBI_STS field 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 to get an IBI status for a rejected MR request. Otherwise, the controller moderates the IBI status generation for rejected MR requests.

If the MR response control is set to 0, then the controller responds to the MR request with ACK and sets the IBI_STS field to ACK, which indicates the application that the controller has ACKed the received MR request.

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

Note: In master-only, if the received IBI ID (MR) does not match with any of the dynamic address entry of the DAT table, then 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.