The debugging console pins (UART) can check the booting and system log message while system is running. It is very important for debugging purpose.
We can use a TTL-to-USB console cable to connect the debugging consoles and PC/Laptop USB port. Then we can get the output log message by setting proper baud rate and corresponding port number.
For example, Bubblegum is one standard reference board of S500 reference platform, the UART connector is J1.