Detecting Dead Bus

When the Target application randomly requests an IBI (In-Band Interrupt) or CRR (Controller Role Request) and finds no response within 50 ms (expected to be handled by the application), it is treated as a Dead Bus scenario. The sequence of steps to initiate the IBI/CRR is as follows:

Set I3CxTGTINT[SIRCTRL] = 01/00b (to raise IBI/CRR) and I3CxTGTINT[SIR] = 1b. Program an external timer with 50 ms. The Target application waits for a response based on the polling or interrupt method.

Polling Method: Poll I3CxTGTINT[SIR]. If it is 0, then there is no error scenario, and reset the timer. Otherwise, if the timer expires and I3CxTGTINT[SIR] is still not 0, then the I³C bus is in Dead Mode, and it is recommended to follow the recovery sequence.

Interrupt Method: The Target application must wait for the IBI completion status interrupt I3CxINTSTA[IBIUPDSTA] and then read the I3CxTGTIBIRESP[IBISTAT] field to check if the Controller accepts IBI. In the meantime, if the timer expires and the application layer does not receive any interrupt, then the I³C bus is in Dead mode and should follow the recovery sequence.