when i giv the getkey() commmand, the hyperterminal doesn't accept any value. However i am able to transmit from serial port to hyperterminal using sendchar or printf.. eg, sendchar (65); this displays A, as it should
But if i give : int i; printf ("enter your choice 1/2/3"); i=getkey(); sendchar(i);
this does not accept anything at the hyperterminal only the message after printf is displayed.
Please help...
I did not talk about any modem. I did talk about modem lines. Your serial port contains more signals than just RX, TX and GND. You have RTS (Ready To Send) and CTS (Clear To Send) for example.
When the Hyperterminal is configured to use hardware handshake, it will make use of these extra signals to find out if it is OK to send more data to the external hardware. In the same way, it will use these signals to inform external hardware that it is ok to send to the PC.
If your development board do not make use of these sinals, then the ARM program will always be allowed to send to the PC. But unless you wire the signals together or connect them between PC and development board, the PC will be forbidden to talk.
If you turn off hardware handshake in Hyperterminal, then any extra handshade signals will be ignored, and the Hyperterminal will send out data as soon as it has more data to send.