Precautions for using timer_cap.c of Jerry [chapter]

、 The timer captures the highest frequency mainly by the clock source ( Generally choose STD24、STD48、LSB( Reference question 7 Map in ))、 Division coefficient ( Minimum No Can be less than 2 frequency division )、 Interrupt function ( Increase interrupt priority 、 Put the interrupt function in RAM) influence . 3、 To achieve the maximum capture speed, you can set the system clock 128Mhz above (LSB 64Mhz)、 Clock source selection LSB、 Select two frequency division for frequency division coefficient 、 Rewrite interrupt function ( The public interrupt function is polled )、 Put the interrupt function in RAM