59 lines
1.1 KiB
C
59 lines
1.1 KiB
C
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#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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// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ҫ<EFBFBD><D2AA>ʱ<EFBFBD><CAB1><EFBFBD><EFBFBD> = <20>ӳ<EFBFBD><EFBFBD><CEA2><EFBFBD><EFBFBD> * ÿ<C3BF><CEA2><EFBFBD><EFBFBD>ʱ<EFBFBD><CAB1><EFBFBD><EFBFBD>
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ticks = _us * (SystemCoreClock / 1000000);
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// <20><>ȡ<EFBFBD><C8A1>ǰ<EFBFBD><C7B0>SysTickֵ
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told = SysTick->VAL;
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while (1)
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{
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// <20>ظ<EFBFBD>ˢ<EFBFBD>»<EFBFBD>ȡ<EFBFBD><C8A1>ǰ<EFBFBD><C7B0>SysTickֵ
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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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// <20><><EFBFBD><EFBFBD><EFBFBD>ﵽ<EFBFBD><EFB5BD><EFBFBD><EFBFBD>Ҫ<EFBFBD><D2AA>ʱ<EFBFBD><CAB1><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>˳<EFBFBD>ѭ<EFBFBD><D1AD>
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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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