Timed GPIO (TIME_SYNC)

The PCH supports 2 Timed GPIOs as native function (TIME_​SYNC) that is multiplexed on GPIO pins. The intent usage of the Timed GPIO function is for time synchronization purpose.

Timed GPIO can be an input or an output.

• As an input, a GPIO input event triggers the HW to capture the PCH Always Running Timer (ART) time in the Time Capture register. The GPIO input event must be asserted for at least 2 crystal oscillator clocks period in order for the event to be recognized.
• As an output, a match between the ART time and the software programmed time value triggers the HW to generate a GPIO output event and capture the ART time in the Time Capture register. If periodic mode is enabled, HW generates the periodic GPIO events based on the programmed interval. The GPIO output event is asserted by HW for at least 2 crystal oscillator clocks period.

Timed GPIO supports event counter. When Timed GPIO is configured as input, event counter increments by 1 for every input event triggered. When Timed GPIO is configured as output, event counter increments by 1 for every output event generated. The event counter provides the correlation to associate the Timed GPIO event (the nth event) with the captured ART time. The event counter value is captured when a read to the Time Capture Value register occurs.