Wake On Proximity Mode

Wake-on-proximity mode is an operating mode that allows the first cycle of any sensor to be used as a wake-up mechanism for the rest of the user interface. To enable this mode, select a sensor to be used as the wakeup sensor via the drop down selection in the controller customizer. By enabling this mode, it is possible to achieve lower power consumption for a system by only updating one time cycle at a slower rate (say, a proximity sensor) until a proximity event on that cycle is detected. At that point, the full user interface will be updated. The sensor selected for wake-on-proximity will be updated in the background with no CPU intervention until one of the following 3 things happens:

1. A proximity threshold crossing was detected on the wake-on-proximity sensor. If the peripheral detects a proximity threshold crossing, a detection interrupt will be issued and the application will switch from autonomous mode to active mode.

2. A negative touch threshold crossing was detected on the wake-on-proximity sensor. If the peripheral detects a negative touch threshold crossing, a detection interrupt will be issued and the application will switch from wake-on-proximity mode to active mode.

3. A conversion counter interrupt condition occurred. The conversion counter interrupt provides a simple way to wake the application after a specified number of conversions has taken place (specified by the Wakeup_Interval parameter). In systems with other sensors, it is advised to wake up the application periodically to update the long term averages (LTA's) of the other sensors in the system, so that environmental drift is accounted for.

Implementation Notes

The Wake_On_Prox_Mode_Scan_Rate_ms parameter specifies the interval at which the wake-on-proximity sensor is updated in hardware. To convert to samples per second (SPS), simply take 1000 divided by the specified report rate period. For example, a report rate (response time) of 50ms would equate to 20 samples per second (SPS).

The Inactivity_Timeout parameter species the amount of time (in samples) to wait before switching from active mode to wake-on-proximity mode after all sensor proximity flags have cleared.

Affected Software Parameters
The Wake_On_Prox_Mode_Scan_Rate_ms parameter corresponds to the ui16WakeOnProxModeScanPeriod member of the tCaptivateApplication type in the CapTIvate Touch Library.
The Inactivity_Timeout parameter corresponds to the ui16InactivityTimeout member of the tCaptivateApplication type in the CapTIvate Touch Library.
The Wakeup_Interval parameter corresponds to the ui8WakeupInterval member of the tCaptivateApplication type in the CapTIvate Touch Library.