How can I implement hardware or software flow control for UART?
UART Flow Control is a way for for slow and fast devices to communicate with each other over UART without the risk of data loss.
Hardware flow control is a form that uses extra wires. The logic level on these wires defines whether the transmitter should continue sending data or not.
Fig: Hardware flow control
Software flow control sends special characters over normal data lines to start or stop transmissions.
Together with the legacy hardware flow control, they make up the three most common ways to implement flow control.
Fig: Legacy hardware flow control
Read the complete application note here for more details on the above and software examples.