Enable/Disable Target Events Command (ENEC/DISEC)

The Controller uses the Direct and Broadcast ENEC/DISEC set of CCCs to control whether Target-initiated traffic is allowed on the bus or not. This governs whether a Target on the bus can perform any of following three requests:

In-Band Interrupt (IBI) Request
Controller Role Request⁽¹⁾
Hot-Join Request

Figure 1 shows the frame format for Direct ENEC/DISEC CCC, whereas Figure 2 shows the frame format for Broadcast ENEC/DISEC CCC. Table 1 and Table 2 show the command byte for ENEC and DISEC respectively. The information received from the Controller is stored in the I3CxEC Event Commands register.

Figure 1. Direct ENEC/DISEC Frame Format

Figure 2. Broadcast ENEC/DISEC Frame Format

Table 1. Enable Target Events Command Byte Format
Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
Reserved				ENHJ	Reserved	ENCR	ENINT

Table 2. Disable Target Events Command Byte Format
Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
Reserved				DISHJ	Reserved	DISCR	DISINT

The ENINT/DISINT (IBIEN bit in the I3CxEC register) allows the Controller to control when a Target can perform an IBI request. When enabled (ENINT), the Controller instructs the Target that performing IBI requests is permitted on the bus. When disabled (DISINT), the Controller instructs the Target that performing IBI requests is not permitted on the bus, and that any such requests may not be honored.

The ENHJ/DISHJ (HJEN bit in the I3CxEC register) allows the Controller to control when a Target can perform a Hot-Join request. When enabled (ENHJ), the Controller instructs the Target that performing Hot-Join requests is permitted on the bus. When disabled (DISHJ), the Controller instructs the Target that performing Hot-Join requests is not permitted on the bus, and that any such requests may not be honored. The Controller can choose to broadcast this CCC to instruct devices to refrain from making Dynamic Address Assignment requests until later authorized by the Controller, in case the Controller is unable to service the Hot-Joining devices.

Important:

1.This I3C Target module does not support Secondary Controller features. Controller role request (ENCR/DISCR) in the command byte will be ignored and the CREN bit in the I3CxEC register will always read ‘0’.