MC9S12GRMV1 Datasheet, PDF (390/1292 Pages) Freescale Semiconductor, Inc – MC9S12G Family Reference Manual and Data Sheet

S12 Clock, Reset and Power Management Unit (S12CPMU)
Figure 10-18. Waveform selected on API_EXTCLK pin (APIEA=1, APIFE=1)
API min. period / 2
APIES=0
API period
APIES=1
MC9S12G Family Reference Manual, Rev.1.23
392
Freescale Semiconductor