systick

SysTick Utils

This utility can be used to initiate a software timer for system delays or non-blocking code execution. An example howto use this library inside a project (with an avr0) can be found here.

The library works with unsigned int which is 16 bit wide on an avr(0) plattform. So a maximum tick sequence of ~16000 can be counted!

File Structure

utils/
└── systick/
    ├── systick.c
    └── systick.h

The library is completely patform independent and can be usesd across a wide range of c-compilers.

Downloads

The library can be downloaded (zip or tar), cloned or used as submodule in a project.

Type	File	Description
Library	zip / tar	SysTick library for counting ticks of a timer over an ISR

Using with git clone

mkdir -p ./utils/
git clone https://github.com/0x007E/utils-systick.git ./utils
mv ./utils/utils-systick ./utils/systick

Using as git submodule

git submodule add https://github.com/0x007E/utils-systick.git ./utils/systick

Programming

#include "../lib/utils/systick/systick.h"
 
SYSTICK_Timer systick_timer;
 
ISR(...)
{
    systick_tick();
}
 
void systick_timer_wait_ms(unsigned int ms)
{
    // If necessary calculate the ticks
    // e.g.:
    // Timer interrupts every us:
    // ms *= 1000;
 
    systick_timer_wait(ms);
}
 
// If the timer ticks fast enough, the systick_timer_wait_us() can be implemented
void systick_timer_wait_us(unsigned int us)
{
    systick_timer_wait(us);
}
 
int main(void)
{
    // Defining of a timer that interrupts every ms or us!
    // ...
 
    systick_init();
 
    // Wait a second blocking
    systick_timer_wait_ms(1000UL);
 
    while(1)
    {
        // Execute every second non-blocking
        if (systick_timer_elapsed(&systick_timer))
        {
            // ...
            systick_timer_set(&systick_timer, 1000UL);
        }
 
        // Return how much time remaining
        unsigned int remaining = systick_timer_remaining(&systick_timer);
 
        // Cancel a timer
        systick_timer_cancel(&systick_timer);
    }
}

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R. GAECHTER