System Tick Timer

The STM32F429ZI offers a 24 bit system tick timer. It is a simple down counter.
The system tick timer counts down from the reload value to zero and generates an interrupt.

Registers

CTRL - Control and status register

ENABLE	0	Systick timer disabled (reset state)
ENABLE	1	Systick timer enabled
TICKINT	0	Systick interrupt disabled (reset state)
TICKINT	1	Systick interrupt enabled
CLKSRC	0	Systick clock ⇒ f_HCLK / 8 (reset state)
CLKSRC	1	Systick clock ⇒ f_HCLK

LOAD - Reload value register

* Reload value of SysTick timer.

VAL - Current value register

* Current value of SysTick timer.

Programming Example

#include "reg_stm32f4xx.h"
 
STK->CTRL = (0x3 << 1u);             /* Set clock and interrupt. */
STK->LOAD = 84000u;                  /* Set reload value: 84 MHz / 84000 -> 1 ms. */
STK->CTRL |= (0x1 << 0u);            /* Enable timer. */
 
void SysTick_Handler(void)
{
    /* Handler for SysTick interrupt. */
}