I also saw the program “How to interface computer’s Serial Port (RS232) with 8051 microcontroller (AT89C51) ” in this website. But I try this experiment as follows: but I am fail.
I use a Keil C emulator to run the C prohram mentioned in about paper on 8051 board which is connected to PC through a device UC232A ( RS232 to UAB cable). when I type the Keyboard of PC, there is nothing to see on Hyperterminal.
I change the C peogram which dowdload from http://www.keil.com/forum/933 and run the program. I got the result as expectation.
Also I do not understand that some sentance such as P1=value and P2=P1-32 in C code.
Please help !
YM Lui