[[File:MPG4_from_cnc4pc.jpg|none|link=|83x169px]]
====Interfacing NPN Devices to KFLOP IO====
NPN devices (open collector)operate as a switch to GND and can be interfaced to KFLOP using a pull up resistor as shown below. When the transistor switches to 0V the KFLOP IO Pin is driven low. The transistor will need to sink ~3ma. When the transistor is off (open circuit) the resistor pulls the IO Pin to 3.3V. Note even though some KFLOP IO Pins can tolerate 5V pulling them above 3.8V should be avoided when possible so the 3.3V supply is used. This technique will only work with KFLOP IO Pins that do not have pull down resistors (JP7 and JP5). In some cases a 0.1uF Ceramic capacitor connected close to KFLOP might be added in parallel with the resistor to filter noise. Cable shielding connected to KFLOP GND on the KFLOP end only is recommended. Note that in noisy environments this technique may couple noise into KFLOP so opto isolation should be used instead.
[[File:NPN_Interface_to_KFLOP.png|none|link=|544x544px]]
==<span id="Axes_Servo_Tuning_and_Trajectory_Planner" class="mw-headline">Axes Servo Tuning and Trajectory Planner</span>==