I went a step further and bought 20 extension cables from China for ~$2 each. I snipped off the “wrong” end of the cable with about six inches of wire (in case I wanted to make a control someday).

[Andy] didn’t want to use up 24 pins on his Arduino, so he used a latch to multiplex the lowest 8 address lines and the data lines together. With the 512KB RAM expansion installed, the Mega is ...