Operation Theory 754.5 CountersThere are four counters for each axis of this motion controller.They are described in this section.Command position counter: counts the number of output pulsesFeedback position counter: counts the number of input pulsesPosition error counter: counts the error between command andfeedback pulse numbers.General purpose counter: The source can be configured as com-mand position, feedback position, manual pulser, or half of ASICclock.Target position recorder: A software-maintained target positionvalue of latest motion command.4.5.1 Command Position CounterThe command position counter is a 28-bit binary up/down counter.Its input source is the output pulses from the motion controller. Itprovides the information of the current command position. It isuseful for debugging the motion system.Our motion system is an open loop type. The motor driver receivespulses from motion controller and drive the motor to move. Whenthe driver is not moving, we can check this command counter andsee if there is an update value on it. If it is, it means that the pulseshave seen sent and the problem could be on the motor driver. Tryto check motor driver’s pulse receiving counter when this situationis happened.The unit of command counter is in pulse. The counter value couldbe reset by a counter clear signal or home function completion.Users can also use a software command counter setting functionto reset it.4.5.2 Feedback Position CounterThe feedback position counter is a 28-bit binary up/down counter.Its input source is the input pulses from the EA/EB pins. It countsthe motor position from motor’s encoder output. This counter
