AT kbds work at 9600,n,8,1 with external clk reference.
surprisingly u dont get the scancodes same as listed in hardware manuals.
xt kbds do not work on async transmission.
we made an emulator based on 8088 long time back, we had to study the serial data sent be xt-kbd by connecting the clk of kbd to serial array of leds i.e the output of one flip-flop to input of another and each output driving a single led. the clock of kbd was given to clk of shift-register thus formed by connecting the ffs.

u may test the scancodes like this and make an emulator based on 8051.

bye