how to configure EXTI ?

[mehmet.karakaya]

Posted on November 07, 2010 at 01:26

how to configure EXTI ?

[Tesla DeLorean]

Posted on May 17, 2011 at 14:14

You must enable the AFIO clock, and the GPIOC clock.

The EXTI registers are within the AFIO unit, chances are you haven't enabled it.

[mehmet.karakaya]

Posted on May 17, 2011 at 14:14

thank you I enabled AFIO clock and it worked

in order not to open a new topic I have another question here I want a timer to tick between 1 Hz  and 10 KHz is there an example for this ? ( how to calculate prescaler and reload register for this job ? )

[Tesla DeLorean]

Posted on May 17, 2011 at 14:14

in order not to open a new topic I have another question here

I want a timer to tick between 1 Hz  and 10 KHz is there an example for this ? ( how to calculate prescaler and reload register for this job ? ) I think I've posted examples before. The basic formula, f = CLK / (p * q), where Prescaler = (p - 1), Period = (q - 1), and where q = less than 65536 I'll post some other examples in a bit.

[Tesla DeLorean]

Posted on May 17, 2011 at 14:14

With SYSTICK. provided your main clock is within range.

SysTick_Config(SystemCoreClock / 10); // 10 Hz SysTick_Config(SystemCoreClock / 10000); 10 KHz   // TIM4CLK = 36 MHz   x = 100; y = 36; // Clock at 1 MHz (36 MHz/36), 100 ticks, 10 KHz or   x = 1000; y = 36000; // Clock at 1 KHz (36 MHz/36000), 1000 ticks, 1 Hz   RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);   /* Time base configuration */   TIM_TimeBaseStructure.TIM_Period = (x - 1); // 1-65536   TIM_TimeBaseStructure.TIM_Prescaler = (y - 1); // 1-65536   TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; // 1,2 or 4 for tDTS   TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;   TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);