SPRUJ28E November 2021 – September 2024 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
In order to accept any Hot-Join (HJ) request from slave device, application needs to set the I3C_CTRL[6] HJ_ACK and I3C_CTRL[8] HJ_DISEC control bits that define its response for Hot-Join request. Based on I3C_CTRL[6] HJ_ACK value the I3C master accepts or refuses the Hot-Join request by providing respectively ACK or NACK bit right after I3C_CMD0_FIFO[0] RNW bit. I3C_CTRL[8] HJ_DISEC bit controls whether master starts DAA procedure or sends broadcast DISEC command to disable HJ requests.
If Hot-Join request occurs, the application processor is notified by the I3C_MST_ISR interrupt. The application processor is aware how this particular Hot-Join request should be handled by checking current setting (can read the control bits or the stored previously used setting). In case of acknowledged request with subsequent DAA, the application processor is notified of automatically completed enumeration of hot-joined device by subsequent I3C_MST_ISR interrupt and simultaneously set I3C_MST_STATUS0 flag. In case of DISEC command, only I3C_MST_ISR interrupt will be set.
It is recommended to keep the I3C_CTRL[6] HJ_ACK bit disabled until the bus initialization procedure is completed in order to prevent slaves from indirect DAA enforcement.