trig_negedge :
A trigger generator for an xbit-typed signal’s falling transition events.

The trig_negedge primitive generates an xbit-typed trigger out when an xbit-typed signal in has the (N+k*P)-th falling transition after a specified delay, where k is 0, 1, 2, and so on. The triggering count N, period P, and delay are defined by the parameters times, period, and delay, respectively. When the parameter times is less than or equal to 0, the primitive triggers out whenever in has a falling transition after the delay. This primitive is equivalent to the trig_edge primitive with the direction parameter set to -1.

The xbit-typed trigger out can be used as an input to the measurement primitives to measure the time instants, delays, periods, etc. of the triggering events. The trigger signal is initialized to X and changes to 1 when the first event occurs. The trigger output out then toggles to a different value (0 or 1) whenever a subsequent event occurs.

Input/Output Terminals

Name	I/O	Type	Description
out	output	xbit	output trigger
in	input	xbit	input signal

Parameters

Name	Type	Default	Unit	Description
delay	real	0.0	seconds	triggering delay
times	integer	0	None	triggering count
period	integer	0	None	triggering period