timeref.h File Reference

Detailed Description

TimeRef and TimeVal define the API for monotonic timers.

The TimeRef API (formerly GenericTimer) provides various methods for measuring elapsed time with a tick-counting time reference.

A SatCat5 design may have many TimeRef objects. The global "timekeeper" (see polling.h) selects one as the preferred general-purpose system reference. Access the system reference using the SATCAT5_CLOCK macro, which returns a TimeRef pointer.

Each TimeRef may be backed by a hardware counter, a timer interrupt, or software. User-defined implementations must meet the following:

• Override the "raw()" method to return the current tick count.
• The counter must tick upwards monotonically at a fixed rate.
  • Supported tick rate of 1 kHz to 1 GHz.
  • Preferred tick rate of 1-100 MHz.
• The counter must rollover from UINT32_MAX back to zero.

SatCat5 provides several reference implementations:

• cfg::Timer (satcat5/cfgbus_timer.h) Backing reference is a ConfigBus hardware timer (cfgbus_timer.vhd).
• freertos::TickTimer (hal_freertos/tick_timer.h) Backing reference is the FreeRTOS system tick (xTaskGetTickCount).
• util::PosixTimer (hal_posix/posix_utils.h) Backing reference is a POSIX monotonic clock (clock_gettime).
• util::TimeRegister (this file) Backing reference is a memory-mapped address.

Definition in file timeref.h.

#include <satcat5/types.h>
#include <satcat5/utils.h>

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Classes
struct	satcat5::util::TimeVal
	Timestamp for measuring elapsed time. More...
class	satcat5::util::TimeRef
	The TimeRef API provides access to a monotonic time-counter. More...
class	satcat5::util::NullTimer
	Placeholder used if no timer is available. More...
class	satcat5::util::TimeRegister
	Implement TimeRef API using a memory-mapped performance counter. More...