SysTick timing problem

[jbl_raw]

Posted on June 01, 2013 at 14:45

the problem is when i make     Delay(1000);  it must delay 1second

but it make delay about 3second not 1second . it was 3time slower than the real time volatile uint32_t msTicks;    void SysTick_Handler(void) {   msTicks++; } void Delay (uint32_t dlyTicks) {                                                 uint32_t curTicks;   curTicks = msTicks;   while ((msTicks - curTicks) < dlyTicks); } SystemCoreClockUpdate();                      /* Get Core Clock Frequency   */   if (SysTick_Config(SystemCoreClock / 1000)) { /* SysTick 1 msec interrupts  */  while (1);                                  /* Capture error              */   }

[Tesla DeLorean]

Posted on June 01, 2013 at 16:36

At a guess, I'd say your HSE_VALUE and/or settings in system_stm32f4xx.c are for an external 25 MHz crystal, and a design (like the F4-Disco) using an 8 MHz crystal. Thus the 3x difference.