For some applications, this shield’s default Arduino pin mappings might not be convenient. For example, maybe you want to use the 16-bit Timer 1 for making music on a buzzer and would rather use PWMs from Timer 0 to control your motor speed. Or maybe you don’t care about monitoring the motor current and would rather use all of your analog inputs for reading sensors. With this in mind, we designed the shield to have break points in the connection between the Arduino pins and the motor drivers. It is easy to cut the connections at these points and establish new connections to replace the broken ones if desired.
The following two diagrams show the default pin mappings:
The connections between the Arduino pins and the MC33926 motor driver pins are each made through a pair of 0.1″-spaced holes that are connected on the of the shield by a thin trace:
The yellow boxes mark the locations where traces can be cut on the underside of the PCB to remap the default Arduino pin assignments. The top through-hole of each vertical pair connects to the Arduino pin and the bottom through-hole connects to the motor driver pin. For the A0 and A1 pairs, which are oriented horizontally, the right pins connect to the Arduino and the left pins connect to the motor drivers (when the shield is viewed from the top side). In the figure above, the pin number label is next to the pin that connects directly to the Arduino.
To change one of the default mappings, simply use a knife to cut the trace between the appropriate pair of holes on the underside of the PCB (there is no connection to cut on the topside of the PCB) and run a wire from a different Arduino pin to the bottom (or left) hole of the pair to create a new connection. You can later use shorting blocks to restore the default pin mapping if you populate the severed hole pairs with 2×1 pieces of the included 0.1″ male header strip.
The pins highlighted in blue in the above diagram are the Arduino header pins and their secondary breakout rows. These pins are also connected by a single trace on the underside of the PCB, and these traces can also be cut if you wish to sever the connection between the breakout point and the header pin.