// IAR 7.1 定時(shí)器中斷時(shí)間依賴系統(tǒng)外部時(shí)鐘

#include "stm32_timer.h"

uint8_t tick = 0;
void stm32_timer_init(void)
{
uint16_t PrescalerValue = 0;
NVIC_InitTypeDef NVIC_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

/* Compute the prescaler value */
PrescalerValue = (uint16_t) (SystemCoreClock / COUNT_CLK) - 1;

/* TIM3 clock enable */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
/* Time base configuration */
TIM_TimeBaseStructure.TIM_Period = COUNT_MAX; //count max number 50000, time 50ms
TIM_TimeBaseStructure.TIM_Prescaler = 0;
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

/* Prescaler configuration */
TIM_PrescalerConfig(TIM3, PrescalerValue, TIM_PSCReloadMode_Immediate);
/* TIM Interrupts enable */
TIM_ITConfig(TIM3, TIM_IT_Update, ENABLE);

/* Enable the TIM3 gloabal Interrupt */
NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}


void stm32_timer_enable(void)
{
/* Clear all the flags */
TIM_ClearITPendingBit(TIM3, 0x00ff);
/* TIM3 enable counter */
TIM_Cmd(TIM3, ENABLE);
}


void stm32_timer_disable(void)
{
/* Clear all the flags */
TIM_ClearITPendingBit(TIM3, 0x00ff);
/* TIM3 disable counter*/
TIM_Cmd(TIM3, DISABLE);
}


void TIM3_IRQHandler(void) //50ms
{
if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET)
{
TIM_ClearITPendingBit(TIM3, TIM_IT_Update);
tick++;
}
}