Creating Timed Events

Currently there are two ways to generate timed events:

• Using the event API (event resolution about 5ms)
• Using the RTOS timer API (event resolution about 1ms)

For long running timers (minutes/hours/days) the Event API should be used.

Using the Event API

• Event API
  • Registering and Unregistering Events
  • gos_event_register_timed
  • gos_event_register_periodic

The event API timer events have the lowest resolution (~5ms) but are the most extensible.

By default the events execute in the App thread. The event can do a lot of work here as the App has a large stack. The resolution is limited by the number of events queued and time it takes for a given event to execute.

Optionally you can specify that the event execute in the Event thread. This thread has a much smaller stack and the events do much less which gives them a better resolution.

Using the RTOS timer API

RTOS timer API events have about a ~1ms resolution. The timer callbacks execute in the RTOS timer context and thus must be non-blocking.

See:

• RTOS Timer
  • gos_rtos_timer_init
  • gos_rtos_timer_start

There is no hard limit to the number RTOS timers or timed/periodic events. The available heap space is the only real limit.

Events with Finer Resolution

For events with a resolution less than 1ms resolution please lodge a support ticket . We can consider implementing a hardware timer API. Note that a Gecko OS app is native C so you have complete access to reading/writing any MCU register.