Abstract:
Disclosed are methods and apparatus for transmitting sensor timing correction messages with a host controller. The methods and apparatus determine synchronization messages that are transmitted to a sensor coupled with the host controller via an interface, where the messages indicate a beginning of a synchronization period for synchronizing timing of the host controller and the sensor. Additionally, a delay time message is determined that indicates a time delay between the beginning of the synchronization period and an actual transmission time of the synchronization message. The synchronization message is transmitted with the delay time message in an information message to the sensor, where information message is configured to allow the sensor to correct timing of a sensor timer by accounting for the delay time.
Abstract:
Disclosed are methods and apparatus for synchronizing a controller and sensors in a system. A timestamp is provided in a host controller of an interface event on an interface coupled with host controller through detecting a message from a sensor on the interface that identifies the issuance of the interface event caused by the sensor at a first time. In response, the controller issues first and second events on the interface at respective second and third times, while concurrently counting cycles of a clock in the controller after each issuance. The controller also receives a first and second sensor counts representing the internal sensor clock times noted for the first and second events. The controller may then accurately calculate the timestamp of the interface event corresponding to the first time based on both internal controller counts and the sensor counts without needing a timestamp from the sensor directly.
Abstract:
Disclosed are methods and apparatus for synchronizing a controller and sensors in a system. A timestamp is provided in a host controller of an interface event on an interface coupled with host controller through detecting a message from a sensor on the interface that identifies the issuance of the interface event caused by the sensor at a first time. In response, the controller issues first and second events on the interface at respective second and third times, while concurrently counting cycles of a clock in the controller after each issuance. The controller also receives a first and second sensor counts representing the internal sensor clock times noted for the first and second events. The controller may then accurately calculate the timestamp of the interface event corresponding to the first time based on both internal controller counts and the sensor counts without needing a timestamp from the sensor directly.