Note: This question does not apply to I3C Basic v1.0.

Yes. The I3C bus supports an optional time control mechanism. One mode is synchronous (from the synchronized timing reference) and four modes are asynchronous (Slave provides timestamp data). All I3C Masters are expected to support at least Async Mode 0.

  • Synchronous: The Master emits a periodic time sync that allows Slaves to set their sampling time relative to this sync. This may be used in conjunction with one of the Asynchronous modes.
  • Asynchronous: The Slaves apply their own timestamp to the data at the time they acquire samples, permitting the Master to time-correlate samples received from multiple different Slaves or sensors.

There are four types of asynchronous time controls:

·   Async Mode 0: Basic mode that assumes that a Slave has access to a reasonably accurate and stable clock source to drive the time stamping – at least accurate for the duration of the time it has to measure (i.e., from event to IBI). A set of counters, in conjunction with IBI, are used to communicate time stamping information to the Master.

·   Async Mode 1: Advanced mode extends the basic mode by using some mutually identifiable bus events like, I3C START.

·   Async Mode 2: High precision mode that uses SCL falling edges (for SDR and HDR-DDR modes) as a common timing reference for Master and Slave. A burst oscillator is used to interpolate the time between a detected event and next SCL falling edge. For HDR-TSL and HDR-TSP modes, the mode uses both SDA transitions and SCL transitions as a timing reference.

·   Async Mode 3: Highest-precision triggerable mode that supports precise time triggering and measurement across multiple transducers applications like beam forming.

FAQ Type: 
I3C