Featured post

Top 5 books to refer for a VHDL beginner

VHDL (VHSIC-HDL, Very High-Speed Integrated Circuit Hardware Description Language) is a hardware description language used in electronic des...

Showing posts with label Suspend. Show all posts
Showing posts with label Suspend. Show all posts

Tuesday, 18 December 2012

Suspend

Formal Definition

Suspend is a process that stops executing and waits either for an event or for a time period to elapse.

Description

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 for statement)
  • a logical condition is met (wait until statement)
  • an event on a signal took place (wait on statement)

See wait statement for details.

Examples

Example 1

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.

Important Notes

  • If no condition is specified in a wait statement, the process suspends forever.