Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 11/27/2024
Public
Document Table of Contents

5.8.6.6.9. Master Request Generation

The I3C controller can generate the Master Request (MR) in non-current master mode to request for I3C bus ownership from the current master.

The application of the I3C controller can decide to send a Master Request by asserting the MR bit in the Slave Interrupt Request register.

The status of the IBI generation is updated in the IBI_STS field of Slave Interrupt Request register (SLV_INTR_REQ), which is informed to the application by the IBI_UPDATED_STS interrupt in INTR_STATUS register by I3C controller. Also after IBI_STS is updated, the MR bit in SLV_INTR_REQ register is auto cleared. On receiving this interrupt, the slave application can read the IBI_STS field in the Slave Interrupt Request register.

Table 269.  Values of IBI_STS
IBI_STS Value Description
Reserved 00 Default value
Success 01 MR accepted by the master (ACK response received).
Reserved 10 Reserved
Not Attempted 11 MR not attempted

The controller does not attempt to issue the IBI and generates the Not Attempted (2'b11) status under the following conditions.

  • Master has not assigned the dynamic address.
  • Master has cleared the assigned dynamic address through RSTDAA.
  • Master has disabled the MR_EN through DISEC CCC (MR_EN in SLV_EVENT_STATUS register).
  • The controller has switched the role to master (applicable only for secondary master configuration).

The following are the SIR-related registers for the I3C controller. For more information, refer to the Address Map

  • IBI_UPDATED_STAT
  • SLV_INTR_REQ
  • SLV_EVENT_STATUS
  • BUS_FREE_AVAIL_TIMING
Note: The application must not assert both Slave Interrupt Request and Master Request together. Once SIR/MR field in SLV_INTR_REQ register is asserted, the application should wait until IBI status is updated by the controller through IBI_UPDATED_STAT interrupt (also SIR/MR bit gets auto cleared), before asserting SIR/MR again.