59 lines
1.1 KiB
C
59 lines
1.1 KiB
C
#include "systick.h"
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__IO uint64_t g_system_tick = 0;
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void systick_config(void)
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{
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/* setup systick timer for 1000Hz interrupts */
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if(SysTick_Config( system_core_clock / 1000U)) {
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/* capture error */
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while(1) {
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}
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}
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/* configure the systick handler priority */
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NVIC_SetPriority(SysTick_IRQn, 0x00U);
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}
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uint64_t get_system_tick(void)
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{
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return g_system_tick;
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}
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void delay_us(uint32_t _us)
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{
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uint32_t ticks;
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uint32_t told, tnow, tcnt = 0;
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// 计算需要的时钟数 = 延迟微秒数 * 每微秒的时钟数
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ticks = _us * (SystemCoreClock / 1000000);
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// 获取当前的SysTick值
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told = SysTick->VAL;
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while (1)
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{
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// 重复刷新获取当前的SysTick值
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tnow = SysTick->VAL;
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if (tnow != told)
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{
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if (tnow < told)
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tcnt += told - tnow;
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else
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tcnt += SysTick->LOAD - tnow + told;
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told = tnow;
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// 如果达到了需要的时钟数，就退出循环
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if (tcnt >= ticks)
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break;
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}
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}
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}
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void delay_ms(uint32_t _ms) { delay_us(_ms * 500); }
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