Step 16 - Resistors and Headers
Use those 100 ohm resistors in between pins 12-19 and the 8 pin male header for each chip. These resistors should be enough,
assuming you're powering 5V from the Arduino. The male headers are used to connect to each of the eight rows of the lattice.
Step 17 - Address Selector
The address selector chip will control the clock cycles to each chip. Start by soldering the GND and VCC connections. If you use the
solder trace method to run GND/VCC lines, you want to do this before you solder any other wires in place. A 100nF ceramic filtering
capacitor is placed close to the VCC and GND pins of the 74HC138.
Then connect the address lines and the eight clock lines.
If you look carefully at the connector, you can see two pins that are not used. These will be used for a button and debug LED later.
