Well i am trying to upgrade my project which has a keyboard like telephone to PS2 keyboard like computers so I tried to understand the concept of PS2 keyboard. It requires only +5Volt and GND and gives data on SDA line along with clock at SCLK line. I was trying it by putting the clock on the INT0 pin of 89c51 and on every falling edge i was reading the status of the SDA line and then rotating it so after 8 falling edges i should get something which has to be make or break code of the Key. But I am not getting any thing. Suggest me if there is a better way to do the same. Or else what shall I do. If u need the piece of code i wrote can send it. with regards Abhinav.
Philips has an appnote something like "converting keyboard to IIC" it is full of info re the keyboard and probably has what you need. Erik Philips appnotes http://www.semiconductors.philips.com/products/all_appnotes/