Omicron CMC 356, Руководство пользователя

Страница: 60 / 142

CMC 356 Reference Manual
60
Deglitching input signals
In order to suppress short spurious pulses a deglitching algorithm could be
configured. The deglitch process results in an additional dead time and
introduces a signal delay. In order to be detected as a valid signal level, the
level of an input signal must have a constant value at least during the
deglitch time. The figure below illustrates the deglitch function.
Figure 6-14:
Signal curve, deglitching
input signals
Debouncing input signals
For input signals with a bouncing characteristic, a debounce function can be
configured. This means that the first change of the input signal causes the
debounced input signal to be changed and then be kept on this signal value
for the duration of the debounce time.
The debounce function is placed after the deglitch function described above
and both are realized by the firmware of the
CMC 356 and are calculated in
real time.
The figure below illustrates the deglitch function. On the right-hand side of
the figure, the debounce time is too short. As a result, the debounced signal
rises to “high” once again, even while the input signal is still bouncing and
does not drop to low level until the expiry of another period T
debounce
.
Figure 6-15:
Signal curve, debounce
input signals
Input signal
Input signal deglitched
T
deglitch
T
deglitch
Input signal
Input signal
debounced
T
debounce
T
debounce
T
debounce