This RS-232 example contains a single FPGA serial read/write example.

Serial is a device communication protocol that sends and receives bytes of information one bit at a time. It is standard on most PCs and is a common communication method with various electrical instruments. Typically, engineers use serial to transmit ASCII data. Communication requires three transmission lines -- ground, transmit, and receive. Because serial is asynchronous, the port can transmit data on one line while receiving data on another. Other lines are available for handshaking but are not required. The important serial characteristics are baud rate, data bits, stop bits, and parity. There are three most common flavors of serial: RS-232, RS-422 and RS-485. They differ in terms of mode of operation (single-ended vs. differential) as well as the number of drivers and receivers that each supports, the allowable cable length and data rates.