I have a system (call it a DTE system). It sends me data (UART) which I receive at a DCE(LPC4337). Now, DTE transmits with 2 stop bits where-as it receives with just 1 stop bit. How is that possible. It would mean I need to interface the to 2 different UARTs in my DCE, right ? Also, supposing I go for full modem(RTS and CTS control), how would this work out ? As I would be using 2 different UARTs to communicate with the same DTE.
Stop bits are effectively an idle signal - sending 2 stop bits just means that the receiver will see an extra 1 bit gap between the characters.
Serial asynchronous data format is: idle (high) start bit (low) data bits (anything) optional parity (anything) stop bit (high) idle(high)
The receiver recognises the start of a character being sent as the first low transition on an idle line (start bit). The number of stop bits is irrelevant.
RTS / CTS control signals are control signals; they do not have any stop bits.