X64-AN Quad User's Manual Theory of Operation 39Camera ControlPulse GeneratorX64-AN Quad has three independent timers per input that control pulse generation for cameracontrols. This allows to position pulses precisely (to a resolution of 1s) relative to the trigger event.Pulse generation flexibility is required to support a wide range of camera control modes (edge pre-select, pulse width control, E-Donpisha, etc.).An independent timer is available for each of the following signals: VS Frame Reset StrobeVS and Frame Reset timers can be combined to generate a double-pulse on the same camera signalcontrol pin. This is required for some camera modes, like long time exposure.Each timer has the following capabilities: Programmable polarity (active high or active low) Programmable delay from trigger event (up to 65 seconds) Programmable duration (up to 65 seconds)Timer granularity (timer step size) is 1s when the delay and duration values are below 65ms.Granularity reduces to 1ms for a delay or duration above 65ms. Delay and duration always have thesame granularity level. Therefore even if only one timer has the reduced granularity of 1ms, all timersthen have the same 1ms step size.Each timer can be started by any of the following events: VS (default) External trigger Internal trigger Software triggerFrame ResetFrame reset—also known as camera reset or camera trigger—is a signal sent by the X64-AN Quad tothe camera which triggers an acquisition. One frame reset signal is available per X64-AN Quad input.The pulse duration and polarity are programmable. Frame reset can be triggered either by an externaltrigger signal, an internal trigger, a software trigger or a VS event. After the trigger is initiated, aninternal frame reset counter counts up to a maximum of 65 seconds. This pulse is normally used tocontrol the exposure of the camera CCD (used with camera modes such as Edge Pre-Select or PulseWidth Control).
