24.4.5.10 Group Address Support in Target

The Group Address feature enables multiple I³C Target Devices to share a single Group Address or multiple Group Addresses, allowing the Controller Device to send a given I³C Message to all Target Devices in the Group at once rather than one at a time.

The Target supports multiple Group Addresses, one address for each Group in which the Target is included, up to a maximum of four. All the Group Addresses are in effect simultaneously.

Target indicates the supported number of Group addresses through GETCAPS

CCC to the Controller. The Target accepts group addresses assigned through SETGRPA CCC until the assigned Group Addresses count reaches four. If the assigned group addresses count exceeds four, then the Target NACKs the SETGRPA CCC.

The assigned Group Addresses can be reset by the Controller using RSTGRPA CCC or RSTDAA CCC.

The Target NACKs the Read transfer issued for a Group Address. If the transfer with the Group address is a Private write transfer or a Broadcast or Directed CCC write (including Vendor-specific write CCC) transfer, then the Target acts upon it as it does with the I³C Dynamic Address.

The Virtual Target, using the shared peripheral logic, reports its Group Address capabilities using the GETCAPS CCC. Each Virtual Target supports multiple groups, up to a maximum of four.

The Target’s shared Peripheral logic matches incoming Private Write transfers addressed to any Group Address and delivers them internally to the appropriate logic for each Virtual Target assigned to that Group Address.