help please

[soul11]

i want to display characters on pc through serial port (rs232) using a 4x4 keypad connected to 8051. so it will be from the keypad to the pc.
please, i will be thankful if anyone can help with the programing by giving me information or sources.
thank you very much

 

[hyedenny]

Hi,
Google for "Scott Edwards Keypad Network Terminal."

He has a nice program, but its written in PBASIC...

 

[tkvenki]

I can tell you briefly about the hardware part.

From keypad to the micro-controller, use a RC network to supress the debounce.( In software also you must use debounce).

THen from the micro-controller use a MAX232. From MAX232 connect to the DB9 connector of serial port. Connect only Tx, Rx, and ground.

In the software part......
You set the baud rate for serial communication.
Enable serial interrupt.
WHat i would to is connect the 16 pins to the GPIO's of the controller. THen On receipt of a valid key-press i would write a switch statement, which would interpret the character intended for display.
Make --> SBUF = "the char yuo want to display"; when you get the data from the keyboard.
In the transmit interrupt clear the TI flag.

This is a very wague idea. You need to refine this.

 

[soul11]

thank you tkvenki, i think this would work

 

[soul11]

ok now i managed to transmite character to the pc using db9 and display them using hyperterminal programe.
what im using is 4x4 keypad to display the numbers and char, so now for char i need to make one button to display 3 char like in mobile phone keypad do anyone has an idea about how to do it.

thank u very much for help