Maximum Read Turnaround Time

The Maximum Read Turnaround time is the time that the Controller will wait before reading the data it requested for Private Transactions. This delay can be specified in the I3CxMRT Maximum Read Turnaround register. This is useful when the user is expecting data read delays for Private Read Transactions due to any reason. The Controller can be notified of this delay by setting the BCR0 bit during setup, to signify that the device is speed-limited. After the Controller reads the I3CxBCR register during the Dynamic Address Assignment process, the Controller can then read the I3CxMRT register by using the Get Maximum Data Speed GETMXDS Common Command Code (CCC). Figure 1 below demonstrates an instance where the Controller waits for the Maximum Read Turnaround time before reading data from the Target.
Figure 1. Example Instance of Maximum Read Turnaround Time
Important: The Controller can choose to not wait for Maximum Read Turnaround time before attempting to read from the Target. If the data is not available in the Transmit FIFO yet, then a Transmit Underrun error is generated, the TXUIF interrupt flag is set, and the read request is NACKed in which case the Controller will attempt to read again. Alternatively, the Target may have the data ready to be read in the Transmit FIFO before the time reported. Refer to Transmit and Receive Buffers section for more information about Transmit Underrun error.