Time simulation API

Create and manage timers in your custom chips

get_sim_nanos

uint64_t get_sim_nanos()

Returns the current simulator (virtual) time in nanoseconds.

You can get the current time in microseconds by calling get_sim_nanos() / 1000, or in milliseconds by calling get_sim_nanos() / 1000000.

timer_init

timer_t timer_init(timer_config_t *config)

Initializes a new timer. Returns the identifier of the timer. Call timer_start() to start the timer, and define the chip_timer_event() callback to response to timer events.

The timer_config_t struct contains the following fields:

Field	Type	Description
callback	callback	Called when the timer fires
user_data	void *	Data that will be passed in the first argument to the callback

The signature for the callback function is as follows:

void chip_timer_callback(void *user_data) {
  /* Called when the timer fires */
}

Note: timer_init() can only be called from chip_init(). Do not call it at a later time.

timer_start

void timer_start(timer_t timer_id, uint32_t micros, bool repeat)

Schedules the timer given by timer_id. The micros argument determines how many microseconds will pass until the timer will call chip_timer_event(). If repeat is false, the timer event will be called once (one-shot timer). If repeat is true, the timer event will keep getting called every micros microseconds, until you call timer_stop() or reconfigure the timer with timer_start.

timer_start_ns

void timer_start_ns(timer_t timer_id, uint64_t nanos, bool repeat)

Similar to timer_start, but specifies the duration of the timer in nanoseconds instead of microseconds. Prefer timer_start() when possible, in order to improve performance.

timer_stop

void timer_stop(timer_t timer_id)

Stops the given timer. If the timer hasn’t fired yet, it won’t fire until you call timer_start() again.