AVAL APX-3302, Руководство пользователя

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APX-3302 User's Manual (OM110000019A)
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6.10.2 Encoder count timing
Double edge evaluation count of using A phase only is as follows.
up
A Phase
up up up
Figure6-27: Double edge evaluation counts of using A phase only
The encoder count of using A phase only performs only addition.
Quad edge evaluation count of using A and B phase is as follows.
up
A Phase
up up
B Phase
up up down
Ignore down
down
down
Figure6-28: Quad edge evaluation count of using A and B phase
Quad edge evaluation count performs addition when A phase is located 90 degrees ahead of B phase. And
it performs subtraction when B phase is located 90 degrees ahead of A phase.
For preventing miscount by noise, it checks phase when it detects each edges, then it specifies the edge
that should be detected.
As shown in the above figure, if phase changes after A phase rising then it waits falling edge of B phase.
Even if the other edges are inputted, they will be ignored.
It is also possible to replace addition and subtraction timing by register control.