Instant Digital Input Acquisition - Advantech AIIS-1882 User Manual

3.1.1.2 Digital Input Pattern Match Interrupt
Digital input channels can also generate an interrupt by detecting a specific pattern.
The pattern can be configured by ports, and each channel can be enabled or dis-
abled the detection independently. For example, if channels 0, 1, 2, 3, 6, and 7 of a
digital input port is pattern match detect enabled, and the pattern is "10xx0100"
(channel 7 through 0, where x indicates a doesn't matter bit), the pattern match inter-
rupt will be generated as shown in Figure 3.6.
Figure 3.4 Digital input pattern match interrupt for pattern "10xx0100".
3.1.1.3 Digital Input Debounce Filter
To prevent false interrupts due to noise or bouncing in the signal, the digital input sig-
nals can be filtered. If digital input filter is enabled, transient signals with duration
smaller than the filter duration will be considered as glitches and will not generate
interrupts as shown in Figure 3.7. Digital input debounce filter can be enabled or dis-
abled independently for each channel, and filter duration can be configured by ports
(8 channels).
3.1.2

Instant Digital Input Acquisition

With instant digital input acquisition, the software controls the sample timing. Each
time the software sends a "read instant digital input sample" command, the state of all
digital input channels is sampled as shown in Figure 3.8.
Figure 3.5 Digital input debounce filter.
Figure 3.6 Instant digital input acquisition.
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