this is the keypad i just bought


1 2 3
4 5 6
7 8 9
* 0 #




it has following pin connection(hand writen so i suspect are wrong) an a paper provided by the seller


NC NC C2 R1 C3 R4 C1 R3 R2


so as the first experiment i connect R1 with +5 and LED to C1 and ground. i was expecting pressing 1 will lit the LED.

now questions.

1- do i still need external components to connect these pins to the 8051

2- my understanding is that rows are coming from the 8051(so 8051 will send 1000 0100 and cols will be going to 8051 (and one of these col pins will contain the 1) or....

so how can i work with this. i want to build some simple circuit with LED's to see is this working.


so can some body guide me how to work with this keypad


Shahzad