plain 64bit carithmetic

ztimer frequency conversion module (64bit arithmetic) More...

Detailed Description

ztimer frequency conversion module (64bit arithmetic)

This ztimer module allows converting a lower-level ztimer clockwith a given frequency to another frequency.

It is configured by passing two parameters (div, mul). Given a lower clock frequency f_low and a desired upper frequency f_upper, div and mul must be chosen such that

(f_upper * mul / div) == f_lower

A div or mul value of 0 is treated as 1 (no multiplication or division by 0 is done).

On every ztimer_set(), the target offset is first multiplied by mul and then divided by div, before passing it to the lower ztimer's ztimer_set().

On every ztimer_now(), the value from the lower ztimer is first multiplied by div and then divided by mul.

Multiplication and division is done using 64bit multiplication / division, thus its use should be avoided in favour of more optimized conversion modules.

Example:

1. if a ztimer_periph_timer with 250kHz is to be "sped up" to 1MHz, use div=4, mul=0
2. if a ztimer with 1024Hz is to be converted to 1000Hz, use div=125, mul=128

Files
file	convert_muldiv64.h
	ztimer frequency conversion module API

Data Structures
struct	ztimer_convert_muldiv64_t
	ztimer_convert_muldiv64 structure More...

Functions
void	ztimer_convert_muldiv64_init (ztimer_convert_muldiv64_t *ztimer_convert_muldiv64, ztimer_clock_t *lower, unsigned div, unsigned mul)
	ztimer_convert_muldiv64 initialization function

Function Documentation

ztimer_convert_muldiv64_init()

void ztimer_convert_muldiv64_init	(	ztimer_convert_muldiv64_t *	ztimer_convert_muldiv64,
		ztimer_clock_t *	lower,
		unsigned	div,
		unsigned	mul
	)

ztimer_convert_muldiv64 initialization function

Parameters

[in]	ztimer_convert_muldiv64	instance to initialize
[in]	lower	lower timer to convert
[in]	div	see module doc
[in]	mul	see module doc