Suspend is a process that stops
executing and waits either for an event or for a time period to elapse.
When a wait statement is
encountered in a process, the process becomes suspended, i.e. it
stops its execution until the condition supported by the wait
statement is met. Depending upon the type of a wait
statement there can be several conditions for resuming (continuing
execution of) a suspended process:
timeout specified has expired (wait
a logical condition is met (wait until statement)
an event on a signal took place (wait
See wait statement for details.
wait until CLK'event and CLK='0';
A process containing such a wait
statement will be suspended until a falling edge on the CLK signal
will be encountered.