I am designing an interface board based on a single UART 8051 family microcontroller.The interface needs two serial port;one for system serial bus and another for networking through a serial-ethernet converter.Is it possible to implement a software UART using two normal pin of micro?Is there any way to share the single UART of the micro for the two puposes? Any solution will be appreciated.
I will use the first solution because of the networking advantage. Go ahead and use a soft UART and see the whole kit and kaboodle blow up in your face. A soft UART basically takes ALL resources and how your networking is going to behave under such circumstances is: NOT. E.g. Philips has some wonderful UARTs with FIFOs that you can use. Another possibility is to use a "throwaway chip" such as a Philips LPC and connect to the main via hardware IIC or SPI. Erik
Erik, I think when he said "the first solution," he was referring to the first of the two dual-UART chips he had listed. He's taking everyone's advice and not disregarding it. By "networking advantage" he just means that the first chip he listed comes with a TCP/IP stack.
A software implementation of a UART on GPIO pins is fairly common. One set of example code can be found at: http://www.programmersheaven.com/zone5/cat27/2369.htm (The number two link on google was http://www.embeddedlogic.com/embarchives/805X/ which error leads to trying http://www.embeddedlogic.com/ Perhaps this is a warning of the fate of anyone that dares to attempt a product without hardware support for all the UARTs?)