Chapter 9

Counters

Output, Counter 0 Gate, Counter 0 Source, or Counter 1 Gate can be routed to Counter 1 Aux.

Some of these options may not be available in some driver software.

Counter n A, Counter n B, and Counter n Z Signals

Counter n B can control the direction of counting in edge counting applications. Use the A, B, and Z inputs to each counter when measuring quadrature encoders or measuring two pulse encoders.

Routing Signals to A, B, and Z Counter Inputs

Each counter has independent input selectors for each of the A, B, and Z inputs. The PFI <0..3> or PFI <8..11> signals can be routed to each input.

Counter n Up_Down Signal

Counter n Up_Down is another name for the Counter n B signal.

Counter n HW Arm Signal

The Counter n HW Arm signal enables a counter to begin an input or output function.

To begin any counter input or output function, you must first enable, or arm, the counter. In some applications, such as buffered semi-period measurement, the counter begins counting when it is armed. In other applications, such as single pulse-width measurement, the counter begins waiting for the Gate signal when it is armed. Counter output operations can use the arm signal in addition to a start trigger.

Software can arm counters or configure counters to be armed on the assertion of the Counter n HW Arm signal.

Routing Signals to Counter n HW Arm Input

Any of the following signals can be routed to the Counter n HW Arm input.

•PFI <0..3>, PFI <8..11>

•ai/ReferenceTrigger

•ai/StartTrigger

Counter 1 Internal Output can be routed to Counter 0 HW Arm.

Counter 0 Internal Output can be routed to Counter 1 HW Arm.