how do i interface a alphanumeric key board with a st10f168 controller in a keil board. thanks
If you mean 'keyboard' as in a 'PC' keyboard, it is a bit more complicated. The PC keyboard uses a clocked open collector bidirectional interface with a protocol going back to the first IBM PC. The transfer is usually at about 12.5 kbaud and the data is coded. You can use the clocked serial port of the '168 with some tricks to maintain the protocol. This is not a trivial task. A good starting point is looking at one of the books from the '80s on PC architecture and the original IBM technical manuals. Best luck