AMX Timing Control
K
A
DAK
83
Operation
The Time/Date Manager includes two components: an AMX Restart Procedure and a set
of service procedures.
If your AMX System Configuration Module enables the Time/Date option, AMX
automatically calls the Time/Date Restart Procedure during the launch prior to executing
any application Restart Procedure. The calendar clock is set to 00:00:00 Monday
October 01/1990 (the distribution date of the Time/Date Manager).
The Time/Date Manager creates a periodic interval timer and starts it with a one second
period. At one second intervals thereafter, the AMX Kernel Task executes the Time/Date
Timer Procedure. The current time and date are updated by one second.
The Time/Date Manager employs an interlock mechanism to ensure that any race
between a task trying to set a new time and date and the Time/Date Timer Procedure
trying to update time and date is resolved. The task's new time and date have precedence.
This interlock mechanism also assures that any task trying to read the current time and
date does not get a partially updated (and hence erroneous) time and date.
Once the time and date have been updated, the Time/Date Timer Procedure calls an
application Scheduling Procedure if one has been provided. This procedure, called once
a second, is thus tied to the calendar clock and can be used to initiate activities which
must be time of day driven. A detailed description of this facility is provided later in this
chapter.
The Time/Date Timer Procedure ends once the application Scheduling Procedure (if an y)
has been executed.