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A realtime clock is an optional feature for Trick simulations.
The Trick::Clock base class provides Trick with a consistent interface to different realtime clocks. The base class provides a common set of routines called by Trick::RealtimeSync to get and reset the realtime clock.
Trick provides built in support for using the system clock (Trick::GetTimeOfDayClock).
Trick also provides built in support for using Spectracom's TPRO IRIG-B clock board, also referred as a Central Timing Equipment (CTE) board. TPRO CTE support is off by default. To enable TPRO CTE support Trick must be built with TPRO driver support. Go to http://www.spectracomcorp.com for driver support for your particular board. To enable TPRO CTE support, run ${TRICK_HOME/configure --tprocte=/paht/to/tpropci. Recompile Trick after the configure script.
Creating a User Defined Real-Time Clock
Clocks may be created by users. To create a new clock, the class must inherit from the Trick::Clock. Trick::Clock is an abstract class with several methods for the user to implement. These methods provide the hardware specific code to initalize, access, and shutdown clock hardware. See ${TRICK_HOME}/trick_source/sim_services/Clock for examples to how we implemented the GettimeofDay and the TPRO_CTE clock. This is the list of routines that must be implemented by the user:
Trick::Clock::clock_init()
Opens the clock hardware, initializes the clock, etc.
Trick::Clock::wall_clock_time()
Gets the wall clock time. Returns the time in integer number of tics of 1us.
Trick::Clock::clock_spin(long long req_time)
Waits for real-time to catch up to the requested simulation time. Polling or waiting for an interrupt are typical methods for spinning.
Trick::Clock::clock_stop()
Shuts down clock hardware, closes devices, etc.
Specifying the Real-Time Clock
Trick instantiates an instance of the Trick::GetTimeOfDayClock by default.
Trick includes a realtime clock based on a TPRO timing card. TPRO support must be enabled when compiling Trick core. A Trick::TPROCTEClock class may be included in an S_define file with ##include "sim_objects/TPROClock.sm".
Trick defaults to the Trick::GetTimeOfDay clock. To switch to the TPRO CTE clock or a user defined clock use the following line in the Python input file.
# Changes to the TPRO CTE clock
trick.real_time_change_clock(trick_tpro.tpro_cte)
# Changes to a user defined clock
trick.real_time_change_clock(<user defined clock>)
Accessing the Real-Time Clock
Typically, users will not have to access the real-time clock directly, the Trick::RealtimeSync uses the real time clock to synchronize to real time. However there are several user accessible routines to control the clock and get the status.
#include "trick_source/sim_services/Clock/include/clock_proto.h" for these routines
Clock Time
long long clock_time() ;
# Python access
trick.clock_time()
Gives you real-time referenced from simulation start. The returned value is in tics. A tic is set amount of time, set by the Trick::Executive, usually 1us.
Wall Clock Time
long long wall_clock_time() ;
# Python access
trick.wall_clock_time()
Gives you the actual time from the clock. The returned value is in tics A tic is set amount of time, set by the Trick::Executive, usually 1us.
Clock Spin
int clock_spin(long long ref) ;
# Python access
trick.clock_spin(<ref_time>)
Calling clock spin will cause the simulation to enter a loop and wait until realtime catches up to simulation time. This is not typically called by users.
Reset Clock Reference
long long clock_reset(long long ref) ;
# Python access
trick.clock_reset(<ref_time>)
Resetting the clock synchronizes the "reference" time to the real-time clock. The reference time is typically the current simulation time.
Manually Setting Clock Reference
int clock_set_reference(long long wall_clock_time) ;
# Python access
trick.clock_set_reference(<wall_clock_time>)
This manually synchronizes the clock's reference to the incoming wall clock time. This routine is used internally to synchronize the simulation time to a whole second multiple of the real time clock.
Getting the Clock Ratio
double clock_get_rt_clock_ratio() ;
# Python access
trick.clock_get_rt_clock_ratio()
The realtime clock has the ability to run at a ratio to realtime. This routine gets the current set ratio.
Setting the Clock Ratio
int clock_set_rt_clock_ratio(double in_rt_clock_ratio) ;
# Python access
trick.clock_set_rt_clock_ratio()
The realtime clock has the ability to run at a ratio to realtime. This routine sets the current set ratio. A simulation may not be able to run fast enough to honor the set ratio. In this case the simulation will run as fast as possible.