consider the mc9s08rd32dwe and reference the documentation:
http://www.freescale.com/files/microcontrollers/doc/data_sheet/MC9S08RG60.pdfthere are 2 kbi channels on this part, kbi1sc functional over 8bits on portA and can be edge andor level. the second is kbi2sc and is a 4bit operating on another port.
more generic documentation:
http://www.freescale.com/files/microcontrollers/doc/ref_manual/HCS08RMV1.pdf?srch=1please be more specific on which part you are using and if multiple channls which chan. even on the above parts, i bet the operation varries somewhat between channels too. so we can help.
note:
are you using the kbi with a keyboard matrix? if so missing a keypress is no big bad since it is a slow operation, lots of contact bounce and if all fails most operators are well trained by microsoft to just try again. if you are looking for another external interrupt consider setting one channel of a tpm port to Input Capture Mode. method see previous posting.