I am using the RXD & TXD of the '51 to communicate with 232 and now i want to use the second port of the 232. How do i go abt doin it since i have exhausted my RXD and TXD. Please Help. ajay
Use a derivative that has two UARTs, use an external UART or 'bit bang' it in software. The last method will not work at high baud rates and may consume too many resources at lower baudrates. Your best bet is to use another derivative.
Stefan Duncanson I did not understand by 'bit bang' can what dose that mean can i use any pins and connect them to 232?
what dose that mean can i use any pins and connect them to 232? yes and no yes you can BUT the software overhead will be enormous and other operations may suffer. Bit banging is not a "good" method, it is a possibility that should be used with extreme caution. If you try this method, first select the dual UART processor you will use, if the bit banging does not allow your code to work succesfully, and assign the bitbang to the same pins as the second set of UART pins on that processor. That way you will, at least, not have to redo the hardware when you find that the bitbang inhibits the operations you need. Somewhere in cyberspace is a method floating around that uses the PCA as a bit-bang controller, that one seems to fall between HW UART and bit-bang in overhead requirements. There is one additional weakness to most bit-bang routines which is that they are much less tolerant of bitrate errors than the HW UART. Erik
"I did not understand by 'bit bang'" See: http://www.8052.com/forum/read.phtml?id=72053
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