Hi Everybody,

I noticed that some weeks ago Oleg Sergeev posted a note asserting that one does not need to enable the serial port interrupts in order to use the 8052 built-in UART.

http://www.8052.com/forum/read.phtml?id=72563

He suggested using the RI and TI bits manually, to see if something had been sent or received, but without the hardware interrupt. I assumed that he is correct from a strictly hardware perspective, and so the suggestion struck me as interesting. Having deliberated the idea I think I disagree, but I'm not yet sure and it seems to me a worthy topic for discussion.

Here are my thoughts. If one were using enough of the RS232 handshaking signals it would be possible to manually monitor the UART. However, with the UART uperating in full duplex asynchronous mode, without the benefit of handshaking, the risk of missing something would be high. On the other hand, in the context of some limited applications it might be possible to write the code such that receipt confirmations were handled in software and the manual approach could be made to work.

So here's my question. Can one think of a time, a specific application or circumstance, where such an approach would be favored or worthwhile? Is there possibly a circumstance wherein one would prefer to handle the UART manually? Or is the hardware interrupt just too convenient?

Joe Hebert

P.S. I know that my use of the term "manually" is at least technically incorrect in this posting, but I expect you all know what I mean. If any of you can suggest a better word to describe "... with software or firmware only, and without the use of hardware interrupts," I will welcome the suggestion.