SysTick.c

//***********************************************************//
//
// SysTick.c - standard functions for tiva TM4C123GH6PM System Delay
//
//***********************************************************//
//
// this software standarizes some functions for TM4C123GH6PM 
// tiva ware for the ease of use and learning
//
//***********************************************************//
//
// AUTHOR : Abderlahman Mostafa
// E-mail : boboelahlawy1234@hotmail.com
// for any questions and inquiries, please send an e-mail or 
// make it as a github pull request
//
//***********************************************************//
//
// THIS WAS MADE WHILE LEARNING THE INTRODUCTION TO EMBEDDED
// SYSTEMS COURSE AT FACULTY OF ENGINEERING, AIN SHAMS UNIVERSITY
//
//***********************************************************//

#include "stdtiva.h"

void SysTick_Init(void) {
	NVIC_ST_CTRL_R    = 0;					//disable counter
	NVIC_ST_RELOAD_R  = 0x00FFFFFF; 		//setting maaximum value of reload
	NVIC_ST_CURRENT_R = 0;					//resetting current
	NVIC_ST_CTRL_R    = 0x00000005; 		//enabling the counter
	// CTRL set to 0101 (CLK_SRC => SYSTEM CLOCK, INTERRUBT => 0,ENABLE => 1)
}

void SysTick_Wait(uint32_t delay) {
	NVIC_ST_RELOAD_R = delay - 1;
	NVIC_ST_CURRENT_R = 0;
	while ((NVIC_ST_CTRL_R&0x00010000)==0) {}
	//keep looping while bit 16 toggles (counter reaches 0)
}



void SysTick_delay(uint32_t delay) {
	unsigned long i;
	for (i = 0; i < delay; i++)
		SysTick_Wait(8000);
}

void SysTick_delayus(uint32_t delayus) {
	unsigned long i;
	for (i = 0; i < delayus; i++)
		SysTick_Wait(8);
}