The following figure illustrates the threshold unit operation. The diagram shows three thresholds, a, b, and c, each configured in a different threshold mode. In hardware all threshold units have independent threshold levels and delay values. In this example the threshold levels are indicated by the dashed horizontal lines, and all units use the same levels for the purpose of illustration. The delay value is set to 5 (the delay value has no effects for Sticky Over mode), and the sticky thresholds have been set up to be cleared by different clear modes. The behavior is described in the following sections.
Threshold-A, Sticky Over Mode
The flag asserts when the first sample exceeds the upper
threshold value. In this example, the flag is cleared using a call
Threshold-B, Sticky Under Mode
The flag asserts when the samples have been continuously
below the lower threshold for the delay number of samples (6, in the
example). In this example, the flag is cleared through an update of
the QMC Gain value, which is issued using a call to the
XRFdc_SetQMCSettings API function,
followed by an Update event, which applies the QMC gain update.
Threshold-C, Hysteresis Mode
The flag asserts when the first sample exceeds the upper threshold value. The flag is cleared when the samples have been continuously below the lower threshold for the delay number of samples.