Generic Timestamping Engine (GTE) Application (app/gte-app.c)

This section explains how to use the generic time-stamping engine (GTE).

The generic timestamping engine snoops a set of signals, timestamps any change on them and presents the timestamped events to SW via FIFOs. There are three GTE instances/slices available to AON/SPE each 32bits wide; details about signals mapping to slices could be found in gte-tegra-hw.h. The application demonstrates the GTE driver APIs and works in tandem with gpio-app to monitor the interrupt on the GPIO_APP_IN line. For guidance on regarding wiring details, see GPIO Application.

GTE ISR is called when the FIFO reaches the GTE_FIFO_OCCUPANCY threshold. On successful execution, GTE ISR following message:

Event Id, Edge = "rising/falling", Time stamp = xxx

The "ENABLE_GTE_APP" flag in the soc/*/target_specific.mk file controls how this app is compiled.

The GTE sample app enables monitoring of the GPIO interrupt event through GTE slice 1 and that interrupt events are generated with GPIO_APP_IN GPIO. The sample app also monitors activity on GPIO_APP_IN GPIO, through GTE slice 2 and records the time stamp for the input value change.