For one of my up coming Labs for EE445L I am going to need to expand the I/O of the LM3S1968. I am using the 74HCT595 much like on my pinball machine. One 74HCT595 allows you to turn 3 output pins into 8 output pins. They can be daisy chained so you can have any multiple of 8 output pins for those 3 original output pins.

In this demo I have 3 74HCT595 chips wired up. Instead of using the SSIO ports on the LM3S1968 I bit banged the port. SSIO is built in hardware that does serial communication. I decided to not use is for the 74HCT595’s because I am going to use it in controlling a DAC.

The code is fairly module and easy to change to different ports and pins.

Link to the code.