Power disconnect unit for use in data transport topology of network on chip design having asynchronous clock domain adapter sender and receiver each at a separate power domain

A method of powering-off a power domain unit, comprising:

• connecting requests from an initiator to a target, through a master side manager, a first asynchronous clock domain adapter sender, a first asynchronous clock domain adapter receiver, and a slave side manager;
• connecting responses to the requests, from the target to the initiator, through the slave side manager, a second asynchronous clock domain adapter sender, a second asynchronous clock domain adapter receiver, and the master side manager;
• receiving a request to power off a first power domain;
• upon receiving the request to power off the first power domain,
• fencing new requests received from the initiator, and
• draining pending responses to the requests from the slave side manager, wherein fencing new requests received from the initiator includes sending an error to the initiator, or stalling the request datapath;
• upon draining pending responses to the requests, resetting the second asynchronous clock domain adapter sender;
• and turning off power to the first power domain,
• wherein the master side manager, the first asynchronous clock domain adapter sender and the second asynchronous clock domain adapter receiver are in the first power domain, and wherein the slave side manager, the second asynchronous clock domain adapter sender and the first asynchronous clock domain adapter receiver are in a second power domain.

A method of powering-off a power domain unit, comprising:

• connecting requests from an initiator to a target, through a master side manager, a first asynchronous clock domain adapter sender, a first asynchronous clock domain adapter receiver, and a slave side manager;
• connecting responses to the requests, from the target to the initiator, through the slave side manager, a second asynchronous clock domain adapter sender, a second asynchronous clock domain adapter receiver, and the master side manager;
• receiving a request to power off a first power domain;
• upon receiving the request to power off the first power domain,
• fencing new requests received from the initiator, and
• draining pending responses to the requests from the slave side manager, wherein fencing new requests received from the initiator includes sending an error to the initiator, or stalling the request datapath;
• upon draining pending responses to the requests, resetting the first asynchronous clock domain adapter sender;
• and
• turning off power to the first power domain,
• wherein the master side manager, the first asynchronous clock domain adapter sender and the second asynchronous clock domain adapter receiver are in the first power domain, and wherein the slave side manager, the first asynchronous clock domain adapter receiver and the second asynchronous clock domain adapter sender are in a second power domain.

A power disconnect unit, comprising:

• a master side manager, configured to receive requests from an initiator, wherein the master side manager is in a first power domain and in a first clock domain;
• a request datapath, comprising an asynchronous clock domain adapter sender and an asynchronous clock domain adapter receiver, configured to connect requests from the master side manager to a second power domain and to a second clock domain, wherein the asynchronous clock domain sender is in the first power domain, and the asynchronous clock domain adapter receiver is in the second power domain;
• a slave side manager, in the second power domain and in the second clock domain, configured to connect requests from the request datapath to a target, and configured to receive, from the target, responses to the requests;
• and
• a response datapath, comprising an asynchronous clock domain adapter sender in the second power domain and an asynchronous clock domain adapter receiver in the first power domain, configured to connect, from the slave side manager to the master side manager, responses to the requests;
• wherein the master side manager is configured to receive a request to power off the first power domain and, upon receiving the request to power off the first power domain, to
• fence new requests from the initiator,
• drain pending responses to the requests from the slave side manager, wherein to fence new requests from the initiator includes to send an error to the initiator, or to stall the request datapath,
• disable the asynchronous clock domain adapter receiver in the first power domain,
• cause the slave side manager to disable the asynchronous clock domain adapter receiver in the second power domain, and to disable and reset the asynchronous clock domain adapter sender in the second power domain, and
• disable the asynchronous clock domain adapter sender in the first power domain and reset the asynchronous clock domain adapter sender in the first power domain.