Flow control in USBUART

Question: How do I implement Flow Control in USBUART?

 

Answer:

There are two types of flow control used in serial ports:

  1.   Hardware flow control - It uses the DTR and RTS signals.  This type of flow control is not possible with the USBUART as the physical data transfer takes place on the USB interface.
  2.   Software flow control (XON/XOFF protocol) -f In this XON/XOFF protocol is implemented in software.  XON/XOFF protocol is controlled by the data recipient who sends an XOFF character (Cntrl+S or 13H) to the sender if it is unable to continue to receive data. The sender suspends transmission until it receives an XON character (Cntrl+Q or 11H).  It should be possible to implement this method using the USBUART by writing appropriate code in the application layer (the user module does not have code to do this). The application should send the XON and XOFF signals depending on its readiness to receive data from the host.