Reconciling events in multi-node systems using hardware timestamps

An electronic eyewear device comprising:

• a frame adapted to fit a head of a user;
• at least two nodes within the frame having independent time bases;
• an electrical or optical connection connecting the at least two nodes;
• a computer readable medium coupled with a first node of the at least two nodes, the computer readable medium comprising instructions stored thereon that are executable by the first node to cause the first node to perform operations for synchronizing the independent time bases of the at least two nodes, the operations performed by the first node including:
• generating a pulse on the electrical or optical connection, the pulse arriving at the at least two nodes in a time interval that is at least an order of magnitude shorter relative to a time interval of a margin of error for synchronization of the at least two nodes;
• recording a timestamp of receipt of the pulse;
• querying at least one other node of the at least two nodes for a timestamp of receipt of the pulse at the at least one other node;
• comparing a timestamp of receipt of the pulse by the first node with a timestamp of receipt of the pulse from the at least one other node;
• and
• using a difference in the timestamp of receipt of the pulse by the first node with the timestamp of receipt of the pulse from the at least one other node to align the time bases of the first node and the at least one other node.

A non-transitory computer readable medium comprising instructions stored thereon that are executable by a first node of an electronic eyewear device to cause the first node to perform operations to synchronize the first node with a second node of the electronic eyewear device, the first and second nodes having independent time bases, the operations comprising:

• generating a pulse on an electrical or optical connection connecting the first and second nodes, the pulse arriving at the first and second nodes in a time interval that is at least an order of magnitude shorter relative to a time interval of a margin of error for synchronization of the first and second nodes;
• recording a timestamp of receipt of the pulse;
• querying the second node for a timestamp of receipt of the pulse at the second node;
• comparing a timestamp of receipt of the pulse by the first node with a timestamp of receipt of the pulse by the second node;
• and
• using a difference in the timestamp of receipt of the pulse by the first node with the timestamp of receipt of the pulse by the second node to align the time bases of the first node and the second node.