ADLINK PCIe-7350 - Manual (Page 81)

Function Block and Operation Theory 71
3.11 COS (Change of State) Event
PCIe-7350 supports COS (Change of State) Event to monitor if
there is any change on the user-defined or any data lines.
When PCIe-7350 detects the change (either the input state
changes from low to high or from high to low) of data input lines,
PCIe-7350 will have the following response:

Generate a pulse signal of change detection event to AFI

Generate the change detection interrupt to host PC

Latch the corresponding DI data into change detection latch
register
In COS mode, the DI data are sampled by 125 MHz clock rate.
Therefore, the pulse width of the DI data should be longer than
8ns. Otherwise, the change detection latch register won’t latch the
correct input data.
Figure 4-15 is an example of 8 channel change detection opera-
tion. Any level change of the enabled DI data lines will be detected
and then generate the event and interrupt. The corresponding DI
data will be latched into change detection register.
Figure 3-41: Example of Pattern Match
DI data of enabled CH
Change Detection
Latch Register
Sampled clock
Change Detection Event
Change Detection Interrupt
128 75 234 3
75 234 3 0