Hello..
 
I have two questions concerning the 8051 microcontroller and its serial port.
 
 
Question No1.
 
I wonder if there is a way i can convert the serial port of a 80C51 into a serial port with CSMA/CD (Carrier Sense Multiple Access with Collision Detection). I don't mind using any external circuitry or 8051 port pins as long as i use the serial port of the 8051 and not a networking peripheral. Note that the serial comunication will not be using a baud speed of more than 19200. Plus i will be interfacing the serial port to a RS-485 or RS-422 transceiver and not RS-232 due to the long distances between every node.
 
Question No2.
 
Is there a way i can connect the 8051 with the parallel port of a PC ? I think i must use a 74HCT543 latching transceiver. The bus connection must be bi-directional. However i need to be able to control one or two more pins from the parallel port for interrupt request (pin no1) and discrimination of address/data/command (pin no1 or even pin no1 and no2). Note that the parallel port will be connected to a 8051 based system that will be used as the primary server for an RS-485 network of many 8051 based systems.
Is there a site where i can find some serious information on the PC parallel port (pdfs) ??
 
 
P.S. There is no need to answer to both questions.
 
Thank you in advance for any help...
 
Panos Kenterlis
Technological and Educational Institute of Piraeus
Athens - Greece