Infineon CCU6 Interrupt 1 Manual page 9

Implementation
Period calculation example
Target: set a period frequency of f = 10 Hz
ISR
Considering the maximum value of the period (65535) and the final ISR frequency that needs to be achieved
(10 Hz), the ISR frequency formula from the previous slide leads to the following:
10 Hz = ( CCU6 clock frequency ) / ( period + 1 ) = ( CCU6 clock frequency ) / ( 65535 + 1 )
which leads to: CCU6 clock frequency = ( 65535 + 1 ) * 10 Hz = 655360 Hz
Since the maximum value of 65535 for the period cannot be exceeded, it is needed to search into the previous
table for the nearest lower exact frequency available, which is 390625 Hz.
Taking this value, the period can be easily re-calculated as:
) – 1 = ( 390625 / 10 ) – 1 ≈ 39061
period = ( CCU6 clock frequency / f
ISR
Finally, selecting these values as period and CCU6 clock frequency, f can be calculated:
ISR
= ( CCU6 clock frequency ) / ( period + 1 ) = 390625 / 39062 ≈ 10 Hz
f
ISR
9
2019-10-17 Copyright © Infineon Technologies AG 2019. All rights reserved.